Global Positioning System
Challenges in Sustaining and Upgrading Capabilities Persist Gao ID: GAO-10-636 September 15, 2010The Global Positioning System (GPS) provides positioning, navigation, and timing (PNT) data to users worldwide. The U.S. Air Force, which is responsible for GPS acquisition, is in the process of modernizing the system. Last year GAO reported that it was uncertain whether the Air Force could acquire new satellites in time to maintain GPS service without interruption. GAO was asked to assess (1) the status of Air Force efforts to develop and deliver new GPS satellites, the availability of the GPS constellation, and the potential impacts on users if the constellation availability diminishes below its committed level of performance; (2) efforts to acquire the GPS ground control and user equipment necessary to leverage GPS satellite capabilities; (3) the GPS interagency requirements process; and (4) coordination of GPS efforts with the international PNT community. To do this, GAO analyzed program documentation and Air Force data on the GPS constellation, and interviewed officials from DOD and other agencies.
The Air Force continues to face challenges to launching its IIF and IIIA satellites as scheduled. The first IIF satellite was launched in May 2010--a delay of 6 additional months for an overall delay of almost 3 1/2 years--and the program faces risks that could affect subsequent IIF satellites and launches. GPS IIIA appears to be on schedule and the Air Force continues to implement an approach intended to overcome the problems experienced with the IIF program. However, the IIIA schedule remains ambitious and could be affected by risks such as the program's dependence on a ground system that will not be completed until after the first IIIA launch. The GPS constellation availability has improved, but in the longer term, a delay in the launch of the GPS IIIA satellites could still reduce the size of the constellation to fewer than 24 operational satellites--the number that the U.S. government commits to--which might not meet the needs of some GPS users. Multiyear delays in the development of GPS ground control systems are extensive. In addition, although the Air Force has taken steps to enable quicker procurement of military GPS user equipment, there are significant challenges to its implementation. This has had a significant impact on DOD as all three GPS segments--space, ground control, and user equipment--must be in place to take advantage of new capabilities, such as improved resistance to jamming and greater accuracy. DOD has taken some steps to better coordinate all GPS segments. These steps involve laying out criteria and establishing visibility over a spectrum of procurement efforts. But they do not go as far as GAO recommended last year in terms of establishing a single authority responsible for ensuring that all GPS segments are synchronized to the maximum extent practicable. Such an authority is warranted given the extent of delays, problems with synchronizing all GPS segments, and importance of new capabilities to military operations. As a result, GAO reiterates the need to implement its prior recommendation. The GPS interagency requirements process, which is co-chaired by officials from DOD and DOT, remains relatively untested and civil agencies continue to find the process confusing. This year GAO found that a lack of comprehensive guidance on the GPS interagency requirements process is a key source of this confusion and has contributed to other problems, such as disagreement about and inconsistent implementation of the process. In addition, GAO found that the interagency requirements process relies on individual agencies to identify their own requirements rather than identifying PNT needs across agencies. The Department of State continues to be engaged internationally in pursuit of civil signal interoperability and military signal compatibility, and has not identified any new concerns in these efforts since GAO's 2009 report. Challenges remain for the United States in ensuring that GPS is compatible with other new, potentially competing global space-based PNT systems. GAO recommends that the Department of Defense (DOD) and the Department of Transportation (DOT) develop comprehensive guidance for the GPS interagency requirements process. DOD did not concur with the recommendation, citing actions under way. DOT generally agreed to consider it. GAO believes the recommendation remains valid.
RecommendationsOur recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.
Director: Cristina T. Chaplain Team: Government Accountability Office: Acquisition and Sourcing Management Phone: (202) 512-4859GAO-10-636, Global Positioning System: Challenges in Sustaining and Upgrading Capabilities Persist
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Report to the Subcommittee on National Security and Foreign Affairs,
Committee on Oversight and Government Reform, House of Representatives:
United States Government Accountability Office:
GAO:
September 2010:
Global Positioning System:
Challenges in Sustaining and Upgrading Capabilities Persist:
GAO-10-636:
GAO Highlights:
Highlights of GAO-10-636, a report to the Subcommittee on National
Security and Foreign Affairs, Committee on Oversight and Government
Reform, House of Representatives.
Why GAO Did This Study:
The Global Positioning System (GPS) provides positioning, navigation,
and timing (PNT) data to users worldwide. The U.S. Air Force, which is
responsible for GPS acquisition, is in the process of modernizing the
system. Last year GAO reported that it was uncertain whether the Air
Force could acquire new satellites in time to maintain GPS service
without interruption. GAO was asked to assess (1) the status of Air
Force efforts to develop and deliver new GPS satellites, the
availability of the GPS constellation, and the potential impacts on
users if the constellation availability diminishes below its committed
level of performance; (2) efforts to acquire the GPS ground control
and user equipment necessary to leverage GPS satellite capabilities;
(3) the GPS interagency requirements process; and (4) coordination of
GPS efforts with the international PNT community. To do this, GAO
analyzed program documentation and Air Force data on the GPS
constellation, and interviewed officials from DOD and other agencies.
What GAO Found:
The Air Force continues to face challenges to launching its IIF and
IIIA satellites as scheduled. The first IIF satellite was launched in
May 2010”a delay of 6 additional months for an overall delay of almost
3-½ years”and the program faces risks that could affect subsequent IIF
satellites and launches. GPS IIIA appears to be on schedule and the
Air Force continues to implement an approach intended to overcome the
problems experienced with the IIF program. However, the IIIA schedule
remains ambitious and could be affected by risks such as the program‘s
dependence on a ground system that will not be completed until after
the first IIIA launch. The GPS constellation availability has
improved, but in the longer term, a delay in the launch of the GPS
IIIA satellites could still reduce the size of the constellation to
fewer than 24 operational satellites”the number that the U.S.
government commits to-”which might not meet the needs of some GPS
users.
Multiyear delays in the development of GPS ground control systems are
extensive. In addition, although the Air Force has taken steps to
enable quicker procurement of military GPS user equipment, there are
significant challenges to its implementation. This has had a
significant impact on DOD as all three GPS segments-”space, ground
control, and user equipment-”must be in place to take advantage of new
capabilities, such as improved resistance to jamming and greater
accuracy. DOD has taken some steps to better coordinate all GPS
segments. These steps involve laying out criteria and establishing
visibility over a spectrum of procurement efforts. But they do not go
as far as GAO recommended last year in terms of establishing a single
authority responsible for ensuring that all GPS segments are
synchronized to the maximum extent practicable. Such an authority is
warranted given the extent of delays, problems with synchronizing all
GPS segments, and importance of new capabilities to military
operations. As a result, GAO reiterates the need to implement its
prior recommendation.
The GPS interagency requirements process, which is co-chaired by
officials from DOD and DOT, remains relatively untested and civil
agencies continue to find the process confusing. This year GAO found
that a lack of comprehensive guidance on the GPS interagency
requirements process is a key source of this confusion and has
contributed to other problems, such as disagreement about and
inconsistent implementation of the process. In addition, GAO found
that the interagency requirements process relies on individual
agencies to identify their own requirements rather than identifying
PNT needs across agencies.
The Department of State continues to be engaged internationally in
pursuit of civil signal interoperability and military signal
compatibility, and has not identified any new concerns in these
efforts since GAO‘s 2009 report. Challenges remain for the United
States in ensuring that GPS is compatible with other new, potentially
competing global space-based PNT systems.
What GAO Recommends:
GAO recommends that the Department of Defense (DOD) and the Department
of Transportation (DOT) develop comprehensive guidance for the GPS
interagency requirements process. DOD did not concur with the
recommendation, citing actions under way. DOT generally agreed to
consider it. GAO believes the recommendation remains valid.
View [hyperlink, http://www.gao.gov/products/GAO-10-636] or key
components. For more information, contact Cristina Chaplain at (202)
512-4841 or chaplainc@gao.gov.
[End of section]
Contents:
Letter:
Background:
The Air Force Continues to Face Challenges to Launching Its Satellites
as Scheduled, Which Could Affect the Availability of the Baseline GPS
Constellation:
Exploitation of New Satellite Capabilities Delayed Further Because of
Ground Control and User Equipment Delays and Acquisition Challenges:
The GPS Interagency Requirements Process Is Relatively Untested and
Lacks Detailed Guidance:
Coordination of GPS Activities with the International Community
Continues, and Some Challenges Have Been Addressed:
Conclusions:
Recommendation for Executive Action:
Agency Comments and Our Evaluation:
Appendix I: Scope and Methodology:
Appendix II: GAO Assessment of GPS IIIA Prime Contractor Schedule
Management Processes:
Appendix III: Comments from the Department of Defense:
Appendix IV: GAO Contact and Staff Acknowledgments:
Tables:
Table 1: GPS Satellite and Ground Control Segment Modernization:
Table 2: Delays in Delivery of New GPS Ground Segment Capabilities:
Table 3: Status of Completion of Interagency Requirements Process Key
Steps for Requirements Initiated after the Development of the GPS
Interagency Requirements Process:
Table 4: Schedules and Their Descriptions:
Table 5: Extent to Which Each Project Schedule Met Best Practices:
Table 6: Antenna Element Schedule Analysis Details:
Table 7: Bus Schedule Analysis Details:
Table 8: General Dynamics Schedule Analysis Details:
Table 9: Navigation Unit Panel Schedule Analysis Details:
Table 10: Launch Operations Schedule Analysis Details:
Figures:
Figure 1: GPS Operational System:
Figure 2: National Space-Based PNT Organization Structure:
Figure 3: Comparison of Predicted Size of GPS Constellation (at the 95
Percent Confidence Level) Based on Reliability Data and Launch
Schedules as of March 2009 and December 2009:
Figure 4: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 2-Year GPS III Launch Delay and
Reliability Data and Launch Schedules as of March 2009 and December
2009:
Figure 5: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 1-Year GPS III Launch Delay and Current
Management and Power Management Reliability Data and Launch Schedules
as of December 2009:
Figure 6: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 2-Year GPS III Launch Delay and Current
Management and Power Management Reliability Data and Launch Schedules
as of December 2009:
Abbreviations:
CAM: Control Account Manager:
CWBS: Contractor Work Breakdown Structure:
DASS: Distress Alerting Satellite System:
DOD: Department of Defense:
DOT: Department of Transportation:
EELV: Evolved Expendable Launch Vehicle:
EVM: earned value management:
FAA: Federal Aviation Administration:
FNET: Finish No Earlier Than:
FOUO: For Official Use Only:
GPS: Global Positioning System:
IFOR: Interagency Forum for Operational Requirements:
IMP: Integrated Master Plan:
IRP: Interagency Requirements Plan:
JCIDS: Joint Capabilities Integration and Development System:
JROC: Joint Requirements Oversight Council:
L1C: fourth civil signal:
L2C: second civil signal:
L5: third civil signal:
M-code: Military Code:
NASA: National Aeronautics and Space Administration:
NSPD-39: National Security Presidential Directive No. 39:
OCS: Operational Control Segment:
OCX: Next Generation Control Segment:
PNT: positioning, navigation, and timing:
SAASM: Selective Availability Anti-Spoofing Module:
SLR: Satellite Laser Ranging:
SNET: Start No Earlier Than:
SOW: Statement of Work:
SVN-49: satellite vehicle number 49:
WBS: Work Breakdown Structure:
[End of section]
United States Government Accountability Office:
Washington, DC 20548:
September 15, 2010:
The Honorable John F. Tierney:
Chairman:
The Honorable Jeff Flake:
Ranking Member:
Subcommittee on National Security and Foreign Affairs:
Committee on Oversight and Government Reform:
House of Representatives:
The Global Positioning System (GPS)--a space-based satellite system
that provides positioning, navigation, and timing (PNT) data to users
worldwide--has become essential to U.S. national security and a key
component in economic growth, transportation safety, homeland
security, and critical national infrastructure in the United States
and abroad. The Department of Defense (DOD) develops and operates GPS,
and an interdepartmental committee--co-chaired by DOD and the
Department of Transportation (DOT)--manages the U.S. space-based PNT
infrastructure, which includes GPS. The U.S. Air Force, which is
responsible for GPS acquisition, is in the process of modernizing GPS
to enhance its performance, accuracy, and integrity. Effective
modernization depends on aligned delivery of new capabilities from
satellites, the ground control segment, and user equipment.
In April 2009, we reported on a range of issues related to GPS,
[Footnote 1] including the development of satellites, ground control,
and user equipment necessary to leverage GPS capabilities and the
coordination among federal agencies and other organizations to ensure
that GPS missions can be accomplished. We reported that it was
uncertain whether the Air Force would be able to acquire new
satellites in time to maintain current GPS service without
interruption, and that some military operations and some civilian
users could be adversely affected. In addition, we reported that
military users faced a potential delay in utilizing new GPS
capabilities because of poor synchronization of the development of the
satellites with development of the ground control and user equipment.
We also reported that DOD and civil agencies involved in ensuring that
GPS can serve communities beyond the military took prudent steps to
manage GPS requirements and coordinate among the many organizations
involved with GPS, but we identified challenges in ensuring that
civilian requirements can be met. Finally, we identified challenges in
ensuring that GPS was compatible with other new, potentially competing
global space-based PNT systems.
In our prior report, we recommended that the Secretary of Defense
appoint a single authority to oversee the development of GPS,
including DOD space, ground control, and user equipment assets, to
ensure that the program is well executed and resourced and that
potential disruptions are minimized. Furthermore, we specified that
the appointee should have the authority to ensure that all GPS
segments are synchronized to the maximum extent practicable. DOD
concurred with this recommendation. In concurring with our
recommendation, DOD asserted that the Assistant Secretary of Defense
for Networks and Information Integration has authority and
responsibility for all aspects of GPS, and that the Air Force is the
single acquisition agent responsible for synchronizing GPS segments.
In addition, after our 2009 report, DOD created the Space and
Intelligence Office within the Office of the Under Secretary of
Defense for Acquisition, Technology and Logistics to ensure that all
three segments of GPS stay synchronized in the development and
acquisition processes. However, that office does not have authority
over all user equipment. We also recommended that if weaknesses are
found the Secretaries of Defense and Transportation should address
civil agency concerns for developing requirements, improve
collaboration and decision making, and strengthen civil agency
participation. Both DOD and DOT concurred with this recommendation.
DOD noted that it would seek ways to improve civil agency
understanding of the DOD requirements process and would work to
strengthen civil agency participation. DOT indicated that it would
work with DOD to review the process and improve civil agency
participation.
In light of our previous findings and the importance of GPS, you asked
that we review the program this year. In response, we assessed (1) the
status of the Air Force's efforts to develop and deliver new GPS
satellites, the availability of the GPS constellation, and the
potential impacts on users if the constellation availability
diminishes below its committed level of performance; (2) efforts to
acquire the GPS ground control and user equipment necessary to
leverage GPS satellite capabilities; (3) the GPS interagency
requirements process; and (4) coordination of GPS efforts with the
international PNT community.
To assess the status of DOD's efforts to develop and deliver new GPS
satellites, including the recently developed GPS IIF satellites and
the GPS IIIA satellites that are under development, we interviewed DOD
officials who manage and oversee the GPS program; reviewed and
analyzed program plans and documentation related to cost,
requirements, program direction, acquisition schedules, and launch
schedules; and reviewed some of the GPS IIIA space vehicle development
schedules and compared them with relevant best practices. To assess
the availability of the GPS constellation, we conducted our own
analysis based on GPS reliability data provided by the Air Force and
assessed the implications of potential schedule delays. To assess
potential impacts on users if the constellation availability
diminishes below its committed level of performance, we obtained
information from all military services and key civil agencies and
departments. To assess the progress of efforts to acquire the GPS
ground control and user equipment, we interviewed officials who manage
and oversee these acquisitions; reviewed documentation regarding the
delivery of capabilities and equipment; and assessed the level of
synchronization among satellites, ground systems, and user equipment.
To assess the GPS interagency requirements process, we reviewed policy
and guidance on the GPS interagency requirements process, identified
the status of civil requirements, analyzed documents, and interviewed
DOD officials from offices that manage and oversee the GPS program and
officials from DOT and other civil departments and agencies. To assess
coordination efforts with the international global PNT community, we
interviewed officials at the Department of State and at the GPS Wing.
Our work is based on the most current information available as of
April 16, 2010. Additional information on our scope and methodology is
in appendix I. We conducted this performance audit from July 2009 to
September 2010 in accordance with generally accepted government
auditing standards. Those standards require that we plan and perform
the audit to obtain sufficient, appropriate evidence to provide a
reasonable basis for our findings and conclusions based on our audit
objectives. We believe that the evidence obtained provides a
reasonable basis for our findings and conclusions based on our audit
objectives.
Background:
GPS is a global PNT network consisting of space, ground control, and
user equipment segments that support the broadcasts of military and
civil GPS signals. Each of these signals includes positioning and
timing information, which enables users with GPS receivers to
determine their position, velocity, and time 24 hours a day, in all
weather, worldwide.
GPS began operations with a full constellation of satellites in 1995.
Over time, GPS has become vital to military operations and a
ubiquitous infrastructure underpinning major sections of the economy,
including telecommunications, electrical power distribution, banking
and finance, transportation, environmental and natural resources
management, agriculture, and emergency services. GPS is used by all
branches of the military to guide troop movements, integrate logistics
support, enable components underlying battlespace situational
awareness, and synchronize communications networks. In addition, U.S.
and allied munitions are guided to their targets by GPS signals and
GPS is used to locate military personnel in distress.
Civil agencies, commercial firms, and individuals use GPS and GPS
augmentations[Footnote 2] to accurately navigate from one point to
another. Commercial firms use GPS and GPS augmentations to route their
vehicles, as do maritime industries and mass transit systems. In
addition to navigation, civil departments and agencies and commercial
firms use GPS and GPS augmentations to provide high-accuracy, three-
dimensional positioning information in real time for use in surveying
and mapping and other location-based services. The aviation community
worldwide uses GPS and GPS augmentations to increase the safety and
efficiency of flight. GPS and GPS augmentations are also used by the
agricultural community for precision farming, including farm planning,
field mapping, soil sampling, tractor guidance, and crop scouting; the
natural resources management community uses GPS for wildfire
management and firefighting, pesticide and herbicide control, and
watershed and other natural resources asset management. GPS is
increasingly important to earth observation, which includes
operational roles in weather prediction, the measurement of sea level
change, monitoring of ocean circulation, and mitigation of hazards
caused by earthquakes and volcanoes. GPS helps companies and
governments place satellites in precise orbits, and at correct
altitudes, and helps monitor satellite constellation orbits. The
precise time that GPS broadcasts is crucial to economic activities
worldwide, including communication systems, electrical power grids,
and financial networks.
GPS System Description:
GPS operations consist of three segments--the space segment, the
ground control segment, and the user equipment segment. All segments
are needed to take full advantage of GPS capabilities. (See figure 1.)
Figure 1: GPS Operational System:
[Refer to PDF for image: illustration]
Space segment:
Ground control segment:
Master Control Station;
Ground antenna;
Monitor station.
User segment:
Handheld;
Recreation;
Aviation;
Maritime;
Ground navigation;
Mapping and surveying.
Sources: GAO; Copyright © Corel Corp. All rights reserved (map); Art
Explosion.
[End of figure]
The GPS space segment is a constellation of satellites that move in
six orbital planes approximately 12,500 miles above the earth. GPS
satellites broadcast encrypted military signals and unencrypted civil
signals. The baseline constellation consists of satellites occupying
24 orbital slots--4 slots in each of the six orbital planes. However,
because the U.S. government commits to at least a 95 percent
probability of maintaining this baseline constellation of 24
satellites, the typical size of the constellation is somewhat larger.
Moreover in recent years, because numerous satellites have exceeded
their design life, the constellation has grown to 31 active satellites
of various generations. However, DOD predicts that over the next
several years many of the older satellites in the constellation will
reach the end of their operational life faster than they will be
replenished, thus decreasing the size of the constellation from its
current level, reducing satellite availability, and potentially
reducing the accuracy of the GPS service.
The GPS ground control segment comprises the Master Control Station at
Schriever Air Force Base, Colorado; the Alternate Master Control
Station at Vandenberg Air Force Base, California; 6 dedicated monitor
stations; 10 National Geospatial-Intelligence Agency monitoring
stations; and 4 ground antennas with uplink capabilities. Information
from the monitoring stations is processed at the Master Control
Station to determine satellite clock and orbit status. The Master
Control Station operates the satellites and regularly updates the
navigation messages on the satellites. Information from the Master
Control Station is transmitted to the satellites via the ground
antennas. The U.S. Naval Observatory Master Clock monitors the GPS
constellation and provides timing data for the individual satellites.
The U.S. Naval Observatory Master Clock serves as the official source
of time for DOD and a standard of time for the entire United States.
The GPS user equipment segment includes military and commercial GPS
receivers. A receiver determines a user's position by calculating the
distance from four or more satellites using the navigation message on
the satellites to triangulate its location. Military GPS receivers are
designed to utilize the encrypted military GPS signals that are only
available to authorized users, including military and allied forces
and some authorized civil agencies. Commercial receivers use the civil
GPS signal, which is publicly available worldwide.
GPS Modernization:
In 2000, DOD began efforts to modernize the space, ground control, and
user equipment segments of GPS to enhance the system's performance,
accuracy, and integrity. Table 1 shows the modernization efforts for
the space and ground control segments.
Table 1: GPS Satellite and Ground Control Segment Modernization:
Satellite evolution and capabilities:
GPS IIA/IIR (first launch 1990/1997):
* Broadcasts signals for military and civil users.
GPS IIR-M (first launch 2005):
Includes IIA and IIR capabilities, plus:
* Second civil signal;
* Second military signal;
* Ability to increase signal power to improve resistance to jamming.
GPS IIF (first launch 2010):
Satellite evolution and capabilities: Includes IIR-M capabilities,
plus:
* Third civil signal for transportation safety requirements.
GPS III (first planned launch 2014):
Includes IIF capabilities, plus:
* IIIA: Stronger military signal to improve jamming resistance and
fourth civil signal that is compatible with foreign signals;
* IIIB: Near real-time command and control via cross links;
* IIIC: Improved antijam performance for military users.
Ground control segment and capabilities:
Legacy Operational Control System (various versions 1979–2007):
* Centralized computer mainframe;
* 1970s technology.
Architectural Evolution Plan (came online in 2007):
* Distributed architecture;
* Enables upgrades to the system;
* Controls GPS IIF satellites.
Next Generation Control Segment (planned to come online in 2015):
* Necessary for operation of GPS IIR-M, IIF and III satellites;
* Service-oriented architecture;
* Connects to broader networks.
Source: GAO analysis based on DOD program information and discussions
with DOD officials.
[End of table]
Full use of military and civil GPS signals requires a ground control
system that can manage these signals. Newer software will upgrade the
ground control to a service-oriented or netcentric architecture that
can support "plug and play" features and can more easily connect to
broader networks. To use the modernized military signal from the
ground, military users require new user equipment, which will be
provided by the military GPS user equipment program.
Broader Coordinating Structure:
The 2004 U.S. Space-Based Positioning, Navigation and Timing policy
established a coordinating structure to bring civil and military
departments and agencies together to form an interagency, multiuse
approach to program planning, resource allocation, system development,
and operations. The policy also encourages cooperation with foreign
governments to promote the use of civil aspects of GPS and its
augmentation services and standards with foreign governments and
international organizations. As part of the coordinating structure, an
executive committee advises and coordinates among U.S. government
departments and agencies on maintaining and improving U.S. space-based
PNT infrastructures, including GPS and related systems. The executive
committee is co-chaired by the deputy secretaries of DOD and DOT, and
includes members at the equivalent level from the Departments of
State, Commerce, Homeland Security, the Interior, and Agriculture; the
Joint Chiefs of Staff; and the National Aeronautics and Space
Administration (NASA). Figure 2 describes the national space-based PNT
organization structure.
Figure 2: National Space-Based PNT Organization Structure:
[Refer to PDF for image: organizational chart]
Top level:
White House.
Second level, reporting to White House:
National Executive Committee for Space-Based Positioning, Navigation,
and Timing: Executive Steering Group: Co-chairs: Defense and
Transportation;
* Defense;
* Transportation;
* State;
* Interior;
* Agriculture;
* Commerce;
* Homeland Security;
* Joint Chiefs of Staff;
* NASA;
* Advisory Board: Sponsor: NASA.
Third level, reporting to National Executive Committee for Space-Based
Positioning, Navigation, and Timing:
National Coordination Office: Host: Commerce;
* GPS International Work Group; Chair: state;
* Engineering Forum; Co-chairs: Defense and Transportation;
* Ad hoc working groups.
Source: GAO presentation of National Executive Committee for Space-
Based Positioning, Navigation, and Timing data.
[End of figure]
The departments and agencies have various assigned roles and
responsibilities. For example, the Secretary of Defense is responsible
for the overall development, acquisition, operation, security, and
continued modernization of GPS. The Secretary has delegated
acquisition responsibility to the Air Force, though other DOD
components and military services are responsible for oversight, for
some aspects of user equipment development, and for funding some parts
of the program. DOT has the lead responsibility for coordinating civil
requirements from all civil departments and agencies. The Department
of State leads negotiations with foreign governments and international
organizations on GPS PNT matters and regarding the planning,
operations, management, and use of GPS.
The Air Force Continues to Face Challenges to Launching Its Satellites
as Scheduled, Which Could Affect the Availability of the Baseline GPS
Constellation:
The Air Force faces challenges to launching its IIF and IIIA
satellites as scheduled. The first IIF satellite launched May 27,
2010, almost 3-½ years later than previously planned, and the IIF
program appears to have resolved most outstanding technical issues. In
addition, the program faces risks that could affect the on-orbit
performance of some GPS satellites and subsequent IIF launches. The
GPS IIIA program is progressing and the Air Force continues to
implement an approach that should prevent the types of problems
experienced on the IIF program. However, the IIIA schedule remains
ambitious and could be affected by risks such as the program's
dependence on a ground system that will not be completed until after
the first IIIA launch. Meanwhile, the availability of the baseline GPS
constellation has improved, but a delay in the launch of the GPS IIIA
satellites could still reduce the size of the constellation to below
its 24-satellite baseline, where it might not meet the needs of some
GPS users.
After Long Development Delays, the First GPS IIF Satellite Has Been
Launched, but the Program Faces Longer-Term Challenges in Launching
IIF Satellites as Scheduled:
Last year, we reported that under the IIF program, the Air Force had
difficulty successfully building GPS satellites within cost and
schedule goals, encountered significant technical problems that
threatened its delivery schedule, and faced challenges with a
different contractor for the IIF program.[Footnote 3] These problems
were compounded by an acquisition strategy that relaxed oversight and
quality inspections as well as multiple contractor mergers and moves
and the addition of new requirements late in the development cycle. As
a result, the IIF program had overrun its original cost estimate of
$729 million by about $870 million and the launch of the first IIF
satellite had been delayed to November 2009--almost 3 years late.
Since our last review, launch of the first IIF satellite was postponed
an additional 6 months--for an overall delay of almost 3-½ years--to
May 2010. The first IIF satellite launched May 27, 2010, and the
program appears to have resolved outstanding technical issues. The
satellite was delivered to Cape Canaveral Air Force Station, Florida,
in February 2010 to undergo final testing and preparations for launch.
The GPS Wing[Footnote 4] attributes recent launch delays to launch
vehicle and pad availability issues, but the late discovery of some
technical issues also contributed to the launch delay. According to
the GPS Wing, the technical issues were a result of inadequate
oversight of the contractor earlier in the acquisition. To prevent an
even longer launch delay, the program shipped the second IIF satellite
to Cape Canaveral Air Force Station and conducted extensive system-
level end-to-end tests. This enabled the program to take the time to
address some technical issues on the first satellite while reducing
risk using the second satellite--GPS Wing officials reported that it
saved them approximately 60 days of schedule time.
On-Orbit Performance of IIF Satellites Remains Uncertain:
Although the first IIF satellite has launched, it is uncertain how the
IIF satellites will perform on orbit and it is unclear how well
positioned the program is to address any on-orbit problems without
significantly affecting the IIF schedule. Only after the first
satellite of a new generation, like IIF, has been launched and months
of on-orbit tests have been conducted can a thorough understanding of
its performance be obtained. Previously, the GPS Wing had planned to
mitigate the risk of potential IIF performance issues by launching
some satellites of the prior generation, the IIR-Ms, after the first
IIF launch. Space programs in the past have used this practice to
reduce risk in case there were on-orbit problems with the new
generation of satellites. However, when the delivery of the IIF
satellites was continually delayed, the Air Force launched the
remaining IIR-M satellites to eliminate the Air Force's dependence on
the launch vehicle that was used for previous generations of GPS
satellites.
Two GPS Wing officials expressed concern that the GPS program is now
in a riskier position than it has been for many years because it does
not have any IIR-M satellites in inventory and ready to launch. In
fact, the current IIF production and launch schedules indicate that
there is little margin to address any potential on-orbit performance
issues. Within little over a year after the first IIF launch, three
additional IIF satellites are scheduled to launch and six--half of all
IIF satellites--are scheduled to have completed production. If
problems are identified during on-orbit testing of the first
satellite, the satellites already in production will have to be
retrofitted to correct the deficiencies, which could result in delays
in launching some IIF satellites.
Competition for Launch Resources Could Affect IIF Launch Schedule:
Adding to these challenges, the need to compete for limited launch
resources has increased across national security space programs and is
likely to affect the Air Force's ability to launch GPS IIF as planned.
Until recently, the Air Force made use of four launch facilities on
the East Coast and three on the West Coast to launch its national
security space satellites. However, the Air Force now plans to launch
most national security satellites, including the GPS IIF and IIIA,
using one of two Evolved Expendable Launch Vehicle (EELV) rocket
types--Delta IV or Atlas V. EELV launches are conducted from two
launch facilities on the East Coast and two on the West Coast. With
this transition to relying on the EELV, the Air Force has reduced its
launch facilities from seven to four. The East Coast launch facilities
are in greatest demand, particularly the Atlas V's facility SLC-41.
Not only does the Air Force plan to launch several high-priority
satellites, including four IIF satellites, from that facility over the
next 2 fiscal years, but NASA also plans to use it for the launch of
two extremely time-sensitive missions within that same time period.
However, historically no more than four satellites have been launched
from the SLC-41 facility in a single year, yet eight launches are
planned for that facility in fiscal year 2011. Air Force officials
stated that they are taking steps to improve their capability to
launch more satellites per year on the EELV than in the past.
The Air Force has acknowledged that it will be challenged to achieve
its desired launch plans in the near future and is taking some steps
to address this challenge. For example, the Air Force designed the GPS
IIF satellites to be dual integrated--meaning they can fly on either
the Delta IV or Atlas V launch vehicle--which gives the Air Force more
flexibility than if it had relied on only one type of launch vehicle.
The GPS program in particular plans to request funding to study the
possibility of launching GPS satellites on the West Coast, which has
the potential of offering a broader array of launch options. However,
some of the potential solutions to these launch challenges, such as
launching GPS satellites from the West Coast, are long-term solutions.
Therefore, despite these efforts, the high demand for limited launch
resources will likely affect the GPS program's ability to achieve its
planned launches in the near future.
The GPS IIIA Program Has Adopted Several Best Practices but Faces
Challenges to Launching Its Satellites on Schedule:
Last year, we reported that the Air Force structured the new GPS IIIA
program to prevent mistakes made on the IIF program but that the IIIA
schedule was optimistic. To avoid repeating past problems, the program
was taking measures to maintain stable requirements, use mature
technologies, and provide more contractor oversight. However, we also
reported that the Air Force would be challenged to deliver IIIA on
time because its satellite development schedule was optimistic given
the program's late start, past trends in space acquisitions, and
challenges facing the new contractor. For example, the GPS IIIA
schedule from contract award to first satellite launch is 72 months.
We found that that time period was 3 years shorter than the schedule
the Air Force had achieved under its IIF program as well as shorter
than most other major space programs we have reviewed. Furthermore, we
questioned the reliability of the GPS IIIA schedule because we found
that it did not fully meet best practices.
Since our prior report, we found that the GPS IIIA program appears to
have furthered its implementation of the "back to basics" approach to
avoid repeating the mistakes of GPS IIF and that it has passed a key
design milestone.[Footnote 5] More specifically, the program has
maintained stable requirements, has used mature technologies, and is
providing more oversight than under the IIF program. There have not
been any changes to the program to meet increased or accelerated
technical specifications, system performance, or requirements. All
critical technologies were reported to be mature at program start. The
program held multiple levels of preliminary design reviews to ensure
that the system was ready to proceed into detailed design. The
preliminary design reviews were completed in May 2009, and the program
completed its critical design review in August 2010. Furthermore, GPS
Wing officials stated that they are requiring that the contractor
follow military standards and specifications and that the contractor
and subcontractors use earned value management.[Footnote 6]
Since our last review, the GPS program has also made improvements to
its integrated master schedule. The success of any program depends in
part on having a reliable schedule and we found the GPS IIIA schedule
to be highly integrated and of high quality. In our recent analysis of
the IIIA schedule, we found that processes are in place to ensure that
all activities are captured, are of reasonable duration, and are
assigned resources. Our analysis also shows that in general the
program office updates the schedule on a regular basis and logical
relationships are used to determine important dates. However, our
analysis also revealed instances of unreasonably high total float.
Total float represents the amount of time an activity can slip before
it affects the project finish date and is directly related to the
logical sequencing of activities. High levels of float may interfere
with management's ability to properly align resources to ensure that
critical activities are not delayed. We also found that schedule risk
analysis is performed periodically on the schedule, but some risks may
not be captured in the overall risk analysis because of issues at the
individual project schedule level. Appendix II discusses our
examination of the prime contractor's schedule management process
against best practices criteria in more detail.
Despite these efforts to develop a stable and successful program, the
GPS IIIA program faces challenges to launching its satellites on
schedule. First, the 72-month time period from contract award to first
satellite launch is 3-½ years shorter than the schedule achieved for
the GPS IIF program. Though the GPS IIIA program has adopted practices
that should enable it to deliver in a quicker time frame than the GPS
IIF program, the inherent complexities associated with the design and
integration phases that have yet to be completed will make it
difficult to beat the prior schedule by that order of magnitude. More
specifically, the IIIA program is not simply replicating the IIF
program in terms of design and production. The program is using a
satellite bus, which although it has flown on many satellites in the
past, has not yet been used in medium-earth orbit, an orbit that
requires different control software and production processes, such as
a higher level of radiation hardening. The contractor will add a new
signal, L1C, to the satellite that has not been included on previous
GPS satellites and will also increase the power of the military signal
that has been used on previous satellites. These types of changes can
increase the time it takes to complete the program because some level
of discovery will need to be completed during design and integration
and unanticipated technical problems that arise during these phases
can have reverberating effects.
Second, the time period from contract award to first satellite launch
in the IIIA schedule appears to be compressed compared to what the
program had previously estimated. DOD's fiscal year 2004 funding
request reported a schedule with 84 months from contract award to
first satellite launch, but contract award took place 3 years later
than had been planned while the first IIIA launch was only pushed back
by 2 years, leaving that time period a year shorter than previously
planned--a considerable amount of time given that requirements were
not substantially changed to accommodate the schedule change.
Third, according to GPS Wing officials, the program is trying to
improve the quality of the satellites by requiring that the contractor
follow military standards and specifications. This action is a
positive step; however, using this more rigorous approach is likely to
pose challenges to meeting the IIIA schedule. GPS Wing officials
stated that GPS IIIA is currently the only major space system
acquisition that is requiring the use of military standards and
specifications and it is shouldering much of the burden of
transitioning to these more rigorous standards. Officials report that
some of the standards and specifications are out of date and
familiarity with these standards has been lost. Updating the standards
and specifications along with developing and implementing the
necessary training and testing to apply them takes time and creates
cost pressure.
Lastly, it should be noted that no major satellite program undertaken
by DOD in the past decade has met its schedule goals. The GPS IIIA
program itself has done more than many programs in the past decade to
position itself to meet its dates, but there are still actions that
need to be taken across DOD to enable space programs to meet their
schedule goals. As we testified in March 2010, these include
strengthening the space acquisition workforce, clarifying lines of
accountability and authority, and lengthening program manager tenures,
among others.[Footnote 7]
An additional challenge to launching the IIIA satellites on time is
the GPS IIIA program's dependence on a ground control system that is
currently in development. More specifically, the first block[Footnote
8] of the ground system, called the Next Generation Control Segment,
or OCX, is scheduled to be operational in fourth quarter fiscal year
2015, over 1 year after the launch of the first GPS IIIA satellite.
GPS Wing officials stated that a complete system-level test cannot be
conducted until OCX is available at which point GPS IIIA can become
part of the operational constellation and be set "healthy."[Footnote
9] They also stated that they would prefer not to launch a second GPS
IIIA satellite until the first IIIA satellite is set healthy, meaning
until OCX is available, only one GPS IIIA satellite should be
launched. Yet the planned launch dates for the GPS IIIA satellites
reflect a rapid series of IIIA launches with five launches taking
place within 2 years after the first IIIA launch. If OCX is late, as
some Air Force satellite ground control systems have been, several
IIIA satellites may not be launched as currently scheduled. In October
2009, we reported that three of eight ground control systems were
lagging significantly behind their satellite counterparts. Of the five
that were not behind, some were still experiencing schedule delays;
however, their satellite counterparts were also experiencing delays.
[Footnote 10]
Current GPS Constellation Availability Improves, but a Delay in GPS
III Could Affect GPS Constellation Performance:
To ensure that the GPS constellation can provide PNT information to
GPS users located anywhere on the earth at almost any time of day, the
performance standards for both (1) the standard positioning service
provided to civil and commercial GPS users and (2) the precise
positioning service provided to military GPS users commit the U.S.
government to at least a 95 percent probability of maintaining a
constellation of 24 operational GPS satellites. Last year, we reported
that the estimated long-term probability of maintaining a
constellation of at least 24 operational satellites would fall below
95 percent during fiscal year 2010 and would remain below 95 percent
until the end of fiscal year 2014, at times falling to about 80
percent. We also reported that if a 2-year delay were to occur to the
launch of the first and subsequent GPS III satellites, the U.S.
government would be at a much greater risk of failing to meet this
commitment.
The availability of the constellation has shown considerable
improvement since last year; the Air Force now predicts that the
probability of maintaining a constellation of at least 24 operational
satellites will remain above 95 percent for the foreseeable future--
through at least 2025, the date that the final GPS III satellite is
expected to become operational. However, the long-term impact of a
delay to GPS III could still reduce the guaranteed size of the
constellation to fewer than 24 satellites, which might not meet the
needs of some GPS users. According to the Air Force, the impact of
such a delay could be mitigated somewhat by shutting off a second
payload on GPS satellites to save power and thereby extend the lives
of aging satellites. However, our analysis shows that this approach
alone would have a limited impact on enabling the U.S. government to
meet its commitment to a 95 percent probability of maintaining a 24-
satellite constellation--increasing the predicted size of the
constellation (at the 95 percent confidence level) by 1 satellite.
Constellation Availability Analysis and Its Limitations:
The Air Force, with technical support from the Aerospace Corporation,
calculates satellite lifetime estimates for each on-orbit and
production (not yet launched) GPS satellite based on detailed
reliability analysis of the satellite's primary life-limiting
subsystems. We replicated this analysis for this review using
parameters provided by the Air Force. The Air Force's analysis is used
to generate a reliability function for each satellite--that is, the
probability that the satellite will still be operational as a function
of its time on orbit. Each satellite's reliability function is modeled
as the product of two cumulative probability distributions--one that
accounts for the wear out of life-limiting components and one that
accounts for random failures. Individual satellite reliability
functions can be combined with a launch schedule and launch success
probabilities to predict the constellation availability--that is, the
predicted size of the constellation as a function of time. (See
appendix I for a more complete description of the approach used to
generate the reliability function for each satellite and to combine
these reliability functions into a constellation availability
analysis.)
While the mathematical techniques used to combine satellite
reliability functions are straightforward, the techniques used to
generate the reliability functions themselves have inherent
limitations. In particular, because the reliability functions
associated with new (unlaunched) generations of GPS satellites are
based solely on engineering and design analysis, instead of on-orbit
performance data, the actual reliability of these satellites may be
very different, and reliability functions may need to be modified once
on-orbit performance data become available. For example, while the IIA
satellites were designed to last 7.5 years on average, they have
actually lasted more than twice as long, and the Aerospace Corporation
has had to adjust the reliability functions of these satellites to
account for this difference. Moreover, satellite operators work to
develop innovative operational tactics to maximize the useful life of
each GPS satellite. An official with the 2nd Space Operations
Squadron, which operates and maintains the GPS constellation, noted
that a healthy tension exists between the acquisitions community,
which tends to be conservative in estimating the lifetimes of the
things it acquires, and the operations community, which continues to
evolve new techniques and procedures for getting more life out of old
systems. Nevertheless, the Air Force appears to have a mature process
in place to develop, certify, and routinely update satellite
reliability functions, and we have found no evidence to suggest that
this process is biased toward overly conservative estimates of
satellite lifetimes.
Near-Term Constellation Availability Has Shown Considerable
Improvement Since Last Year:
Last year, we reported that because there were 31 operational GPS
satellites of various generations, the near-term probability of
maintaining a constellation of at least 24 operational satellites
would remain well above 95 percent for a brief period of time, but
because older satellites were predicted to fail faster than they were
scheduled to be replaced, we reported that the constellation would, in
all likelihood, decrease in size. We noted that the probability of
maintaining a constellation of 24 operational satellites would fall to
below 95 percent in fiscal year 2009, and to as low as 80 percent
before recovering near the end of fiscal year 2014. This situation is
now much improved. There are still 31 operational satellites, 30 of
which are currently working to performance standards and available to
GPS users. Our updated analysis, based on the most recent satellite
reliability data, indicates that the size of the constellation is
still expected to decline somewhat over the next several years.
However, if the current launch schedule holds, the probability of
maintaining a constellation of 24 satellites will remain above 95
percent for the foreseeable future. Figure 3 compares the predicted
size of the GPS constellation over time (at the 95 percent confidence
level) that we calculated based on the GPS reliability data and launch
schedule we used last year with the predicted size of the
constellation over time that we calculated based on the latest
available GPS reliability data and launch schedule.[Footnote 11]
Figure 3: Comparison of Predicted Size of GPS Constellation (at the 95
Percent Confidence Level) Based on Reliability Data and Launch
Schedules as of March 2009 and December 2009:
[Refer to PDF for image: multiple line graph]
Date: October 9;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 26;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 32.
Date: October 10;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 11;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 22;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 12;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 22;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 13;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 23;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 14;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 15;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 23;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 24.
Date: October 16;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 17;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 18;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 19;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 25;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 20;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 27;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 21;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 29;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 25.
Date: October 22;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 30;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 24.
Date: October 23;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 30;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 24.
Source: GAO analysis of DOD data.
[End of figure]
The improvement in the near-term predicted size of the constellation
is the result of several factors, most notably the Air Force's
assumptions regarding an increased life expectancy for some of the on-
orbit satellites. Other factors include the successful launches of the
last two GPS-IIR-M satellites in March 2009 and August 2009 and some
adjustments to the launch schedule.
Our updated analysis does not include the contribution of several
residual satellites that have been decommissioned but not yet been
permanently disposed of. These satellites could be reactivated if
there were an unexpectedly large number of satellite failures in the
near future. However, the maximum size of the current constellation is
limited to 31 operational satellites because of limitations of the
current ground system, and none of these residual satellites is
expected to continue operating beyond the end of fiscal year 2013.
Consequently, while including these satellites in our analysis would
further increase the probability of maintaining a 31-satellite
constellation for the next few years, these residual satellites would
have little or no impact on the size of the constellation beyond
fiscal year 2013.
Our updated analysis also assumes that GPS-IIR-M-20--otherwise known
as satellite vehicle number 49 (SVN-49)--will remain operational.
However, while this satellite is currently operational and
broadcasting GPS signals, it has remained in an "unhealthy" status
since it was launched in March 2009, and consequently remains
unavailable to GPS users. The satellite remains unhealthy because of a
small but permanent signal anomaly that could adversely affect GPS
user equipment if it were activated without putting mitigation
measures in place. This anomaly resulted from unexpected complications
following the integration of a demonstration payload onto the
satellite--a payload that broadcasts the third civil signal. The Air
Force is examining several options to mitigate the impact of this
anomaly, but no solution that would work for all GPS users has been
identified. On March 26, 2010, DOT published a request seeking public
comment on the Air Force's proposed mitigation options in the Federal
Register.[Footnote 12] However, a final decision as to whether SVN-49
will be set healthy is not expected to be made until June 2011. If SVN-
49 were excluded from our analysis, the impact would be to reduce the
predicted size of the constellation by about one satellite until
around fiscal year 2020.
A Delay in GPS III Could Still Affect GPS Constellation Availability:
Last year, we reported that a delay in the production and launch of
GPS III satellites could have a big impact on the U.S. government's
ability to meet its commitment to maintain a 24-satellite GPS
constellation. We noted that the severity of the impact would depend
on the length of the delay, and that, for example, a 2-year delay
(which is less than the average delay experienced by major space
programs over the past decade) in the production and launch of the
first and all subsequent GPS III satellites would reduce the
probability of maintaining a 24-satellite constellation to about 10
percent by around fiscal year 2018. Put another way, we predicted that
the guaranteed size of the constellation (at the 95 percent confidence
level) would fall to about 17 satellites by that time. Our updated
analysis based on the latest reliability data and launch schedule
indicate that a 2-year delay in the production and launch of the GPS
III satellites would still lead to a drop in the guaranteed size of
the constellation (at the 95 percent confidence level) to about 18
satellites by fiscal year 2018. See figure 4 for details.
Figure 4: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 2-Year GPS III Launch Delay and
Reliability Data and Launch Schedules as of March 2009 and December
2009:
[Refer to PDF for image: multiple line graph]
Date: October 9;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 26;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 32.
Date: October 10;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 11;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 22;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 12;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 22;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 13;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 23;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 26.
Date: October 14;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 23;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 24.
Date: October 15;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 21;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 22.
Date: October 16;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 19;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 20.
Date: October 17;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 17;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 18.
Date: October 18;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 17;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 18.
Date: October 19;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 19;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 19.
Date: October 20;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 20;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 21.
Date: October 21;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 22;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 22.
Date: October 22;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 22.
Date: October 23;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) –
parameters approved in March 2009: 26;
Predicted size of constellation (95 percent confidence level) –
parameters approved in December 2009: 21.
Source: GAO analysis of DOD data.
[End of figure]
This analysis assumes that the Air Force will be able to launch all 12
IIF satellites on schedule; a slower IIF launch rate would change the
shape of the availability curve--reducing the amount of time that the
guaranteed size of the constellation would remain above 24 satellites-
-but would not reduce the depth of the decline in the constellation's
guaranteed size. Moreover, while the performance of several of the on-
orbit satellites has been somewhat better than was expected last year,
there has been no change to the expected lifetimes of any of the IIF,
IIIA, IIIB or IIIC satellites. Consequently, the predicted size of the
constellation around fiscal year 2018--at a time when the
constellation will be predominantly made up of IIF, IIIA, and IIIB
satellites--is about the same as last year's analysis had predicted.
The drop-off in the predicted size of the constellation in fiscal year
2022 is the result of changes to the approved launch schedule for the
IIIC satellites since last year. While the Air Force still plans to
launch the first IIIC satellite in June 2019, the scheduled launch
dates for the rest of the IIIC satellites have been pushed back from 5
months (for the second IIIC launch) to 28 months (for the 16th and
final IIIC launch).
Employment of Power Management Would Mitigate the Impact of a Delay in
GPS III, but the Effect Would Be Small:
Excluding random failures, the operational life of a GPS satellite
tends to be limited by the amount of power that its solar arrays can
produce. This power level declines over time as the solar arrays
degrade in the space environment until eventually they cannot produce
enough power to maintain all of the satellite's subsystems. The
effects of this power loss can be mitigated somewhat by actively
managing satellite subsystems--shutting them down when they are not
needed--thereby reducing the satellite's overall consumption of power.
The Air Force currently employs this approach--referred to as current
management--to extend the life of GPS satellites. According to the Air
Force, it would also be possible to significantly reduce a satellite's
consumption of power and further extend the life of its PNT mission by
shutting off a second payload on a GPS satellite once the satellite
could not generate enough power to support both the missions. Shutting
off the second payload once the satellite cannot support both missions-
-known as power management--would further mitigate the impact of a
delay in GPS III. However, the impact is limited to increasing the
predicted size of the constellation by about 1 satellite. For example,
if the GPS III program were delayed by 1 year, the guaranteed size of
the constellation (at the 95 percent confidence level) would decline
to about 21 satellites by fiscal year 2017 if current management were
employed and to about 22 satellites if power management were employed.
See figure 5 for details.
Figure 5: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 1-Year GPS III Launch Delay and Current
Management and Power Management Reliability Data and Launch Schedules
as of December 2009:
[Refer to PDF for image: multiple line graph]
Date: October 9;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 32;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 32.
Date: October 10;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 11;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 12;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 28.
Date: October 13;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 14;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 24;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 26.
Date: October 15;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 23;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 24.
Date: October 16;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 21;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 22.
Date: October 17;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 21;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 22.
Date: October 18;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 22;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 23.
Date: October 19;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 23;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 23.
Date: October 20;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 23;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 24.
Date: October 21;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 23;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 24.
Date: October 22;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 23;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 24.
Date: October 23;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 22;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 25.
Source: GAO analysis of DOD data.
[End of figure]
If the GPS III program were delayed by 2 years, the guaranteed size of
the constellation (at the 95 percent confidence level) would decline
to about 18 satellites by fiscal year 2018 if current management were
employed and to about 19 satellites if power management were employed.
See figure 6 for details.
Figure 6: Predicted Size of GPS Constellation (at the 95 Percent
Confidence Level) Based on a 2-Year GPS III Launch Delay and Current
Management and Power Management Reliability Data and Launch Schedules
as of December 2009:
[Refer to PDF for image: multiple line graph]
Date: October 9;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 32;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 32.
Date: October 10;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 11;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 12;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 28.
Date: October 13;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 26;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 27.
Date: October 14;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 24;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 26.
Date: October 15;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 22;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 24.
Date: October 16;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 20;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 21.
Date: October 17;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 18;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 19.
Date: October 18;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 18;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 19.
Date: October 19;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 19;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 20.
Date: October 20;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 21;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 21.
Date: October 21;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 22;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 22.
Date: October 22;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 22;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 23.
Date: October 23;
Committed size of satellite constellation (95 percent confidence
level): 24;
Predicted size of constellation (95 percent confidence level) -
current management parameters approved in December 2009: 21;
Predicted size of constellation (95 percent confidence level) - power
management parameters approved in December 2009: 23.
Source: GAO analysis of DOD data.
[End of figure]
Because the second payload relies on the PNT payload, there would be
no operational benefit to retaining the second payload and shutting
off the PNT payload at the point where a satellite cannot support both
missions. However, the constellation availability analysis that
employs power management does not address whether the constellation is
satisfying the missions supported by the second payload. Moreover,
according to Air Force Space Command officials, power management
should not be used as the basis for official constellation
availability analysis, given the uncertainties associated with
predicting a satellite's actual power usage. We agree, given the
criticality of GPS to military and civilian users.
Potential Effects of a Decline in the Availability of the GPS
Constellation Appear to Be Poorly Understood but Vary Significantly
Depending on Circumstances:
If GPS constellation performance were to fall below the baseline
constellation of 24 satellites, the constellation would continue to
provide a high level of service to most users most of the time,
although accuracy and availability could diminish in some locations
for brief periods. Military users of GPS understand that a diminished
constellation of fewer than 24 satellites will affect their
operations. However, it is unclear whether military users of GPS
understand the potential specific effects. The Army, Marine Corps, and
Navy user representatives reported that their services had not
conducted any studies to assess how their operations would be affected
if the constellation were to drop below 24 satellites. Furthermore,
while some user representatives pointed out that the effects of
diminished constellation availability would vary depending on which
satellites continued to be available, most did not provide very
specific explanations of the potential effects of a decline below
performance standards on their services' operations. For example, the
services reported the following:
* Air Force. The Air Force user representative stated that the Air
Force has "a healthy concern for the ready viability, integrity, and
availability of this system. Specific data points, analysis, and
vulnerabilities would be classified." Any system that would possibly
function without its full designed or optimized capability would
naturally have some operational degradation.
* Army. The Army user representative stated that effects largely
depend on which satellites would remain available. If there is a
decline just below 24 satellites, the effect would probably be
minimal, but with each additional space vehicle lost the operational
impact would increase.
* Marine Corps. The Marine Corps user representative stated that
Marines are accustomed to using GPS for PNT; therefore the loss of GPS
would severely affect Marines' ability to navigate. Effects would vary
depending on the situation in which a user operates. The most severely
affected Marines would be those who use GPS in marginal but currently
acceptable conditions, such as under foliage, in mountains, and in
urban settings, where a smaller constellation is more likely to result
in diminished or no service.
* Navy. The Navy user representative stated that there is no "one-size-
fits-all" answer, that information regarding the effects would be
classified, and that the Navy would continue to operate even if it
could not use GPS, although missions might take longer to accomplish
and require additional assets.
Civil agency officials stated that if the constellation performance
fell below the committed level of service, their operations would be
affected; however, the effects vary by agency. For instance, Federal
Aviation Administration (FAA) officials stated that a constellation
smaller than the committed 24 satellites could result in flight delays
and increased reliance on legacy ground-based navigation and
surveillance systems. Likewise, U.S. Coast Guard officials stated that
they could revert back to older methods of navigation if GPS service
were diminished, but there would be a loss of efficiency. On the other
hand, the National Institute of Standards and Technology, within the
Department of Commerce, relies on GPS for timing data rather than
navigation data and may be less sensitive to decreases in the number
of GPS satellites. Furthermore, some civil agencies rely on both GPS
and augmentation systems. For example, FAA augmentation systems
increase the integrity of GPS for aviation purposes. However,
officials from a few civil agencies explained that the augmentation
systems cannot compensate for a drop in the size of the GPS
constellation below the committed level.
Exploitation of New Satellite Capabilities Delayed Further Because of
Ground Control and User Equipment Delays and Acquisition Challenges:
GPS modernization efforts across the space, ground control, and user
equipment segments introduce new capabilities, such as improved
resistance to jamming and greater accuracy. For most of these new
capabilities, all three segments need to be in place in order for
users to benefit from the new capability. However, the development of
GPS ground control systems has experienced years of delay and in some
cases will delay the delivery of new capabilities to users. In
addition, although the Air Force has taken steps to enable quicker
procurement of military GPS user equipment, there are significant
challenges to these systems' implementation.
Ground Control Challenges:
We previously reported that the Air Force had not been fully
successful in synchronizing the acquisition and development of the
next generation of GPS satellites with the ground control system,
thereby delaying the ability of military and civil users to utilize
new GPS satellite capabilities.[Footnote 13] The delay was due to
funding shifts that were made to resolve GPS IIF satellite development
problems. Since our last report, we found that the Air Force has faced
technical problems and continued to experience delays in upgrading the
capabilities of the current ground control system and that the
delivery date of the follow-on ground system has further slipped.
Table 2 highlights specific new capabilities for which there have been
significant delays in the ground segments and additional delays that
have occurred since last year's review.
Table 2: Delays in Delivery of New GPS Ground Segment Capabilities:
Capability enabled: Selective Availability Anti-Spoofing Module;
Originally planned delivery date: September 2005;
Delivery date reported by GAO in 2009: September 2009;
Delay in months: 48;
Current delivery date: January 2010;
Delay in months: 52.
Capability enabled: Second civil signal;
Originally planned delivery date: September 2007;
Delivery date reported by GAO in 2009: September 2012 or 2013;
Delay in months: 60-72;
Current delivery date: August 2015;
Delay in months: 95.
Capability enabled: Military Code;
Originally planned delivery date: September 2007;
Delivery date reported by GAO in 2009: September 2012 or 2013;
Delay in months: 60-72;
Current delivery date: September 2016;
Delay in months: 108.
Capability enabled: Third civil signal;
Originally planned delivery date: September 2007;
Delivery date reported by GAO in 2009: September 2012 or 2013;
Delay in months: 60-72;
Current delivery date: September 2016;
Delay in months: 108.
Capability enabled: Fourth civil signal;
Originally planned delivery date: May 2013;
Delivery date reported by GAO in 2009: Not previously reported on;
Delay in months: N/A;
Current delivery date: September 2016;
Delay in months: 40.
Source: GAO analysis of GPS Wing data.
[End of table]
Since our 2009 report, the contract for the newest ground system
development effort--known as OCX--was awarded in February 2010, about
10 months later than the original contract award date was to occur. To
account for the delay and increase confidence in the schedule, the Air
Force extended the OCX delivery schedule by adding 16 months of
development time. As a result, key OCX capabilities associated with
the IIIA satellites will not be operational until September
2016[Footnote 14]--over 2 years after the first IIIA satellite launch.
The Air Force is working on a mitigation strategy that calls for
development of a separate effort to launch and control the first IIIA
satellite. However, GPS Wing officials indicated that the effort will
not enable new capabilities offered by IIIA, including a signal known
as Military Code (M-code), which is designed to enable resistance to
jamming, and three civil signals: the second civil signal (L2C), to
improve the accuracy of the other signals; the third civil signal
(L5), to be used for aviation; and the fourth civil signal (L1C), to
offer interoperability with international global space-based PNT
systems.
The other delayed capability identified in table 2 is the Selective
Availability Anti-Spoofing Module (SAASM),[Footnote 15] which will
provide military users with improved security and information
assurance. The ground control system software that precedes OCX
deploys the SAASM functionality, which is a critical enabler of DOD's
navigation warfare strategy. Although new user equipment capable of
exploiting SAASM was delivered to the warfighters in 2004, they were
not able to take full advantage of this capability until January 2010--
when the SAASM module was delivered as part of the ground control
system.
User Equipment Challenges:
GPS has become an essential element in conducting military operations.
GPS user equipment is incorporated into nearly every type of system
used by DOD, including aircraft, spacecraft, ground vehicles, ships,
and munitions. A key component of the GPS modernization is a new
military signal--known as M-code--that will increase the jam
resistance of the GPS military service. For military users to benefit
from this new capability, they need to be provided with new military
user equipment capable of receiving and processing the new military
signal.
In 2009, we found that the Air Force was not fully successful in
synchronizing the acquisition and development of the next generation
of GPS satellites with the user equipment, thereby delaying users'
ability to benefit from M-code. While the signal was to be made
operational by the GPS satellites and ground control system in about
2013 (now 2016), we found that the warfighters would not be able to
take full advantage of this new signal until about 2025--when the
modernized user equipment is completely fielded. We also found that
diffuse leadership was a contributing factor, given that there was no
single authority responsible for synchronizing procurements and
fielding of user equipment. More specifically, while the Air Force was
responsible for developing the satellite and ground segments for GPS,
the military services were individually responsible for procuring user
equipment for the weapon systems they owned and operated. As such,
there were separate budget, management, oversight, and leadership
structures over the space, ground control, and user equipment
segments. While there were valid reasons to segment procurement
responsibility, DOD and GAO studies have consistently found that DOD
has lacked the tools necessary to coordinate these procurements and
ensure that they are synchronized to the extent that warfighters can
take advantage of M-code and other new capabilities available to them
through GPS satellites.
Since our 2009 report, the Air Force has taken steps to enable quicker
procurements of user equipment, but there are still significant
challenges to its implementation. First, the Air Force intends to
follow an acquisition approach that will enable the military services
to contract separately with commercial GPS providers rather than
develop entirely new, customized user equipment systems. To support
this approach, the Air Force plans to develop a common module, which
commercial providers could use, along with interface control
documents, to produce their equipment. The Air Force's current
expectation is that it will issue requests for proposals in February
2011, formally initiate the military user equipment acquisition
program in fiscal year 2012, and begin production in fiscal year 2015.
At this time, however, the Air Force does not have approved
requirements or an approved military user equipment acquisition
strategy.
Second, as a pathway to its new approach, the Air Force is working
with three contractors to develop GPS receiver cards capable of
receiving and processing legacy GPS signals and the new military
signal, while incorporating a new security architecture into the
design. However, the delivery of receiver cards from two contractors
has slipped by about a year because of unforeseen challenges with
software and hardware integration and antispoofing software
development and integration. The third contractor is facing technical
problems, the cause of which has not yet been identified, and the Air
Force is uncertain as to when this contractor will deliver its
receiver card. Even after the cards are developed and delivered, they
still need to go through independent security and technology testing
to demonstrate that the technologies are mature, which can take 9
months to a year. Moreover, since there is still no program of record
for the military GPS user equipment, it is difficult to forecast when
enough military GPS user equipment will be in place to utilize the M-
code capabilities operationally.
Third, some steps have been taken to better coordinate procurements of
user equipment. Specifically, in January 2010, the Office of the Under
Secretary of Defense for Acquisition, Technology and Logistics held
its first annual GPS enterprise review. The purpose of this review,
which will be held again in the fall of 2010, is to review the status
of the GPS acquisition programs at one time and provide more
visibility into how the GPS acquisitions and capabilities fit
together. In addition, DOD recently created the Space and Intelligence
Office within the Office of the Under Secretary for Acquisition,
Technology and Logistics to ensure that all three segments of GPS stay
synchronized in the development and acquisition processes. DOD has
also documented GPS synchronization as one of its goals for the next
15 years in its March 2010 Net-Centric Portfolio Strategic Plan, used
in part to identify areas requiring additional focus. More
specifically, DOD plans to ensure synchronized development and
fielding of GPS space, ground control, and user equipment segments to
support delivery of advanced capabilities. This includes fielding user
equipment to all designated users starting in 2014 and almost
completing fielding by full operational capability of the GPS III
satellite constellation. In DOD's netcentric plan, M-code initial
operational capability is defined as having 18 M-code satellites on
orbit, having the control segment able to command and upload M-code
capabilities to the satellites, and having enough military GPS user
equipment in place across DOD to utilize M-code capabilities
operationally. Furthermore, the Air Force has made significant changes
to the definition of initial operational capability, which now takes
into account all three GPS segments rather than only the satellite
segment.
DOD has taken some steps to coordinate GPS segments, but it is not
likely that these will be sufficient to ensure that all GPS segments
are synchronized to the maximum extent practicable, which we
recommended last year. Specifically, we recommended that the Secretary
of Defense appoint a single authority to oversee the development of
GPS, including DOD space, ground control, and user equipment assets,
to ensure that the program is well executed and resourced and that
potential disruptions are minimized. The creation of the Space and
Intelligence Office is a positive development; however, the office
does not have authority over all user equipment. In addition, we
recently reported that DOD program officials believe that the primary
reason that user equipment is not optimally synchronized is a lack of
coordination and effective oversight of the many military
organizations that either develop user equipment or have some hand in
the development.[Footnote 16]
The GPS Interagency Requirements Process Is Relatively Untested and
Lacks Detailed Guidance:
The GPS interagency requirements process remains relatively untested
and civil agencies continue to find the process confusing. The lack of
detailed guidance on the process is a key source of confusion and has
also contributed to other problems, such as disagreement and
inconsistent implementation of the process. In addition, we found that
the interagency requirements process relies on individual agencies to
identify their own requirements but does not identify PNT needs across
civil agencies.
We previously reported that DOD and civil agencies considered the
process for approving civil GPS requirements rigorous but relatively
untested, and that civil agencies found the process confusing.
[Footnote 17] We stated that prudent steps had been taken to manage
requirements and coordinate among the many organizations involved with
GPS. However, we reported that civil agencies had not submitted many
requirements proposals to date. We focused on two proposals: those for
the Distress Alerting Satellite System (DASS) and the geodetic
requirement implemented by Satellite Laser Ranging (SLR). These
proposals had yet to complete the initial steps in the interagency
requirements process. In addition, we reported that civil agencies
that had proposed GPS requirements found the requirements approval
process confusing and time-consuming. We recommended that if
weaknesses are found the Secretaries of Defense and Transportation
should address civil agency concerns for developing requirements,
improve collaboration and decision making, and strengthen civil agency
participation. Both DOD and DOT concurred with this recommendation.
DOD noted that it would seek ways to improve civil agency
understanding of the DOD requirements process and would work to
strengthen civil agency participation. DOT indicated that it would
work with DOD to review the process and improve civil agency
participation.
GPS Interagency Requirements Process Remains Relatively Untested:
In our current work, we found that the requirements process continues
to be relatively untested and the lack of documentation of the various
stages of the process makes it difficult to determine the extent to
which requirements followed the GPS interagency requirements process.
No new civil requirements have been requested since our prior report;
while DASS and SLR have made some progress, no final decision on
whether these requirements will be included on GPS has been made. In
addition, there are some civil requirements that have already been
included in the DOD requirements document for GPS III, but the extent
to which they were evaluated via the interagency requirements process
is unclear.
The Interagency Forum for Operational Requirements (IFOR), which is co-
chaired by officials from DOD and DOT and includes members from
several agencies, serves as the entry point into the process and is
responsible for receiving and processing new operational requirements
and for clarifying existing requirements. DOT has the lead
responsibility for the coordination of civil requirements from all
civil departments and agencies. Although guidance on the steps in the
interagency requirements process describes a more complex process,
descriptions by officials involved with the process indicate that
there are three key steps in the requirements process with the final
determination of whether a requirement is approved being made by DOD's
Joint Requirements Oversight Council (JROC) in coordination with the
DOT's Extended Positioning/Navigation Executive Committee:
1. Civil agencies are to internally identify and validate their
requirements and conduct cost, risk, and performance analyses.
2. Civil requirements proposals are submitted to IFOR, which is
composed of military and civil working groups. IFOR is then to assist
with preparing civil requirements proposals for a GPS satellite
capability development document.
3. Upon IFOR recommendation, civil requirements enter the Joint
Capabilities Integration Development System (JCIDS), the DOD process
to validate warfighter requirements. DOD's JROC will make the final
determination of whether a requirement will be approved for inclusion
on GPS, which is documented in the JROC-approved capability
development document.
Additional details in the guidance provide more specificity regarding
how these steps are to be implemented and describe additional steps
that may be necessary if there are disagreements or other issues that
require adjudication. In addition, there may be a considerable amount
of communication with the requesting agency and revision during this
process if IFOR or DOD determines that improvements to the
requirements packages are necessary.
As shown below, two requirements, DASS and SLR, formally entered the
interagency requirements process but have not yet completed the review
process. Two other civil requirements were included in the GPS III
capability development document, but as is reflected in table 3, the
lack of documentation of their review makes it difficult to determine
the extent to which the GPS interagency requirements process was
applied for those submissions.
Table 3: Status of Completion of Interagency Requirements Process Key
Steps for Requirements Initiated after the Development of the GPS
Interagency Requirements Process:
Civil requirement: L1C;
Step 1: Civil agency identification, validation, and analysis: No.
Generated via international agreement and sponsored by the White House;
Step 2: IFOR reviews and approves for submission to DOD requirements
process: No. No formal proposal submitted to IFOR, and IFOR did not
conduct a formal review;
Step 3: Requirement is reviewed and approved or rejected by JROC: Yes.
Reviewed and approved by JROC, as reflected in GPS III capability
development document.
Civil requirement: Aviation/navigation integrity;
Step 1: Civil agency identification, validation, and analysis: Yes.
Sponsored by DOT/FAA;
Step 2: IFOR reviews and approves for submission to DOD requirements
process: No. Submitted to IFOR for review; no formal documentation of
IFOR approval prior to JCIDS review;
Step 3: Requirement is reviewed and approved or rejected by JROC: Yes.
Reviewed and approved by JROC, as reflected in GPS III capability
development document.
Civil requirement: DASS;
Step 1: Civil agency identification, validation, and analysis: Yes.
Sponsored by the Coast Guard;
Step 2: IFOR reviews and approves for submission to DOD requirements
process: Yes. IFOR has reviewed requirement;
Step 3: Requirement is reviewed and approved or rejected by JROC: No.
Not yet submitted to JCIDS.
Civil requirement: Geodetic requirement/SLR;
Step 1: Civil agency identification, validation, and analysis: Yes.
Sponsored by NASA and endorsed by other agencies;
Step 2: IFOR reviews and approves for submission to DOD requirements
process: No. Pending review;
Step 3: Requirement is reviewed and approved or rejected by JROC: No.
Not yet submitted to JCIDS.
Source: GAO analysis based on agency information and discussions with
agency officials.
[End of table]
Lack of Detailed Guidance Contributes to Confusion and Disagreement:
Guidance for the interagency requirements process lacks sufficient
detail in areas such as explanations of key terms, documentation
standards, steps in the process, and funding. This lack of detail has
contributed to a number of problems, such as confusion, disagreement
among the agencies involved, and inconsistent implementation of the
process.
Three documents provide guidance specific to the interagency
requirements process. National Security Presidential Directive No. 39
(NSPD-39)[Footnote 18] provides high-level guidance and the GPS
Interagency:
Requirements Plan (IRP)[Footnote 19] and the IFOR charter[Footnote 20]
provide more process-specific guidance. The documents do not define
key terms, such as secondary mission requirement, civil use, and dual
use, nor do they outline how these types of requirements should be
treated in the interagency requirements process. As a result,
distinctions based on informal verbal instructions appear to have
affected how requirements have been treated in the process and could
affect future funding decisions.
* Secondary mission requirements. A secondary mission requirement,
sometimes called a secondary payload, is a requirement that does not
directly support the primary GPS mission to provide PNT information.
The guidance does not define the term nor does it indicate whether or
how a secondary mission requirement should be evaluated via the
interagency requirements process. DASS is considered to be a secondary
mission requirement, and Coast Guard officials involved with the DASS
program report that its review was delayed for several years because
of uncertainty regarding how secondary mission requirements should be
treated in the interagency process. According to those officials, when
the DASS requirement was submitted to IFOR in 2003, the Coast Guard
was told that DASS should not be reviewed via this process because it
was a secondary mission requirement and that it should instead be
submitted directly to DOD's JCIDS requirements process. After several
years of delay, the Coast Guard was informed that DASS should be
reviewed by IFOR after all. IFOR ultimately accepted the requirement
for review in 2008.
* Civil and dual use. According to officials involved with the
interagency requirements process, requirements that are identified by
the civil community are considered initially to be "civil unique" and
may later be determined to have military utility and identified as
"dual use." However, the guidance does not define the terms, nor does
it state how civil unique or dual-use requirements are to be treated
in the process. Even though the guidance does not distinguish between
these two terms, some agencies involved in the process have indicated
that whether a requirement is considered to be civil unique or dual
use should determine how the requirement is funded. For example, NASA
contends that SLR should be considered dual use and that DOD should
therefore partially cover the costs of SLR. According to NASA, both
the civil community and the military would benefit from SLR because it
would improve GPS accuracy. However, some DOD officials disagree. They
stated that there are no military requirements for SLR and that it is
therefore not a dual-use requirement, implying that it should be
funded solely by NASA.
In addition, the guidance provides some information regarding what
types of documents should be submitted, but it lacks specificity,
resulting in confusion and disagreement among the military and civil
agencies involved. The IRP states that cost, risks and performance
trades, and other information will be submitted in order to defend
requirements' feasibility, affordability, and best value for the
government. However, the guidance documents do not specify the type,
level of detail, or formatting requirements for submissions to IFOR.
* There has been a disconnect between the Coast Guard's understanding
of documentation needs and DOD's documentation expectations. To remedy
this, some Coast Guard officials involved with submitting the DASS
requirement stated that a list of required reports and their format
should be provided to civil agencies. These officials said that they
provided IFOR with assessments of six alternatives, but they were told
by DOD officials that the analyses were not adequate. In addition,
although guidance does not indicate that documents should be submitted
using the JCIDS format, Coast Guard officials indicated that some of
the studies they provided in support of the DASS requirement
submission were not accepted because they did not use that format.
* Similarly, NASA officials have expressed frustration with the lack
of clear and consistent guidance on documentation standards. While
NASA officials stated that since 2007 they have provided all the
documentation and analyses on SLR requested by IFOR, DOD officials
stated that SLR has not been fully developed as a requirement.
The guidance also does not explain in detail the steps in the
interagency requirements process. For example, the guidance lacks
detail about formal approvals needed to proceed to the next step in
the process and about standards regarding what is to take place during
each phase of the process. This has resulted in confusion about next
steps for agencies that have submitted requirements and it may also
have contributed to inconsistent implementation of the process.
* Approval requirements. There is limited information in the guidance
on what formal approvals are required, how they are to be documented,
and few details as to when and how these approvals relate to one
another. As a result, civil agency officials have indicated that they
find it difficult to know when a requirement has been approved to move
to the next step in the process or whether it has received final
approval. In the case of SLR, in 2007, IFOR released a memo
recommending that SLR be included in the GPS III capability
development document. However, after some concerns about SLR were
identified within DOD that approval was de facto rescinded. SLR is
again pending IFOR review and approval. Similarly, there appears to be
some confusion about the ultimate fate of some requirements that have
already been included in a capability development document. For
example, some of the aviation-related requirements were included in
the GPS III capability development document for later increments of
GPS III, which are important to meeting the needs of FAA's Next
Generation Air Transportation System program, a satellite-based air
traffic management system that is under development and is expected to
increase the safety and enhance the capacity of the air transport
system. However, some DOD officials report that this capability
development document will be treated as the one for GPS IIIA and that
requirements not included on GPS IIIA will have to be submitted
through JCIDS again on the capability development documents for either
the GPS IIIB or GPS IIIC.
* Phases of the process. The guidance lacks details about specific
phases of the interagency requirements process, which may have
contributed to inconsistent implementation. For example, the guidance
regarding the initial step in the interagency requirements process
states, among other things, that civil agencies are to internally
identify and validate their requirements. However, the requirement for
L1C never went through this phase of the process. Instead, the request
resulted from an international agreement and was submitted by the
White House. In addition, expertise and experience with requirements
and their identification and validation processes vary greatly across
government agencies. DOT and DOD officials report that some agencies
have documented, disciplined requirements processes. However, while
other agencies represent vital GPS applications and users, they have
limited experience with requirements processes because they do not
typically acquire systems to fulfill their missions. Although it may
not be realistic to expect civil agencies to have requirements
processes that are as rigorous as DOD's, more detailed guidance on
expectations regarding standards for identification and validation of
requirements could help ensure that there is more consistency in the
first stage of the process.
Lastly, the guidance does not include criteria for funding decisions
beyond indicating that sponsoring agencies must pay for their
requirements. More specifically, the lack of details in guidance
regarding the required timing of funding commitments has caused
confusion. The process for considering civil GPS requirements is
intended to maintain fiscal discipline by ensuring that only critical
needs are funded and developed. Our past work has shown that
requirement add-ons cause cost and schedule growth.[Footnote 21]
Guidance requires that the agency proposing the requirement pay the
costs associated with adding it to the GPS satellites, thereby forcing
agencies to separate their wants from needs. IFOR has requested that
sponsoring agencies commit to fund a requirement when the requirement
proposal is submitted. For example, IFOR requested that the Coast
Guard provide a funding commitment for DASS before the requirement
enters the JCIDS process. However, information regarding when a
funding commitment is required is not included in guidance on the
interagency requirements process.
Approach to Identify Civil Requirements Does Not Identify PNT Needs
Across Agencies:
The interagency requirements process relies on individual agencies to
identify their own requirements but does not identify PNT needs across
civil agencies. For example, the DASS requirement is a secondary
mission requirement to support a search and rescue system rather than
a performance requirement specific to PNT. While such requirements may
fulfill important needs, they do not reflect civil community
requirements for PNT capabilities. Yet there are considerable
challenges to identifying needs across agencies. For example, civil
agencies have different roles, missions, and priorities ranging from
providing leadership related to food, agriculture, and natural
resources to providing the safest, most efficient aerospace system in
the world. The civil PNT Executive Committee Co-chair pointed out that
most civil agencies have not identified PNT requirements for their
agencies, which poses a considerable challenge to identifying these
requirements across agencies. These challenges have resulted in an
approach that is agency specific and not coordinated rather than a
coordinated national approach to identifying PNT needs.
While there is no standardized process for identifying requirements
across civil agencies, we found that two efforts under way are
attempting to contribute to the development of a coordinated national
approach to identifying PNT requirements. First, DOT officials stated
that they are working with civil agencies to identify PNT requirements
that represent their stakeholder needs with respect to accuracy,
availability, coverage, and integrity. This information would serve as
input for the 2010 Federal Radionavigation Plan, a document that
reflects official U.S. radionavigation policy, which covers
radionavigation systems, including GPS. Second, DOD's National
Security Space Office has been working with civil agencies to develop
a national PNT architecture to address capability gaps and provide a
framework for evaluating and recommending new requirements.
Coordination of GPS Activities with the International Community
Continues, and Some Challenges Have Been Addressed:
Last year, we reported that the State Department has engaged other
planned global navigation satellite system providers bilaterally and
multilaterally in pursuit of compatibility with GPS signals and
services and interoperability with civil GPS signals and service. The
United States has made joint statements of cooperation with several
countries and an executive agreement with the European Community,
although according to State Department officials, this agreement has
not yet been ratified by all European Union members.[Footnote 22]
Additionally, State Department officials reported that they believe
they lack dedicated technical expertise to monitor international
activities. State Department officials stated that they would like DOD
and civil agencies to dedicate funding and staff positions to
international activities accompanied by a sustained level of senior
management support and understanding of the importance of these
activities. Furthermore, U.S. firms had raised a concern to the
Department of Commerce about the lack of information from the European
Commission relating to the process for obtaining licenses to sell
equipment that is compatible with Galileo, a space-based global
navigation satellite system being developed by the European Union.
However, according to the executive agreement with the European
Community, subject to applicable export controls, the United States
and the European Community are to make sufficient information publicly
available to ensure equal opportunity for persons who seek to use
these signals, manufacture equipment to use these signals, or provide
value-added services that use these signals.
State Department officials said that they had no new issues or
concerns to add to what we reported in April 2009. State Department
officials also stated that they continue to engage other planned
global navigation satellite system providers bilaterally and
multilaterally in pursuit of interoperability with civil GPS signals
and compatibility with GPS military signals. According to the
officials we spoke with, there have been no changes in the number or
status of cooperative agreements between the United States and other
countries since April 2009. Furthermore, the State Department reported
that the current number of DOD technical experts needed for
international discussions about foreign global navigation satellite
systems is now sufficient.
Additionally, U.S. GPS industry representatives we met with remain
concerned about the lack of information from the European Commission.
In July 2009, the Office of the U.S. Trade Representative reported to
Congress that industry representatives were concerned about (1) the
lack of information on how to secure licenses to sell products,
protect intellectual property rights, or both; (2) access to signal
test equipment for Galileo's publicly available service; and (3) the
lack of information on the three other Galileo PNT services--service
for safety-of-life applications, an encrypted signal for government
users, and an encrypted service intended for commercial users.
[Footnote 23] However, according to State Department officials, in
spring 2010, the European Commission helped address the first two of
these concerns when it published an updated technical document that
includes information on the process for licensing intellectual
property rights related to Galileo. State Department officials said
that the U.S. government is seeking additional clarification on
Galileo's newly established intellectual property licensing scheme,
which if it is obtained, should address the first concern. State
Department officials explained that the updated technical document
addresses the second concern, regarding access to signal test
equipment for Galileo's publicly available service, and that the U.S.
government will no longer need to pursue the issue.
Conclusions:
Conditions have improved for the near-term size and availability of
the GPS constellation. While DOD has strengthened acquisition
practices for GPS and made concerted efforts to maximize the life of
GPS satellites, it still faces many of the same challenges we
identified last year, as well as new ones we identified this year. For
example, the GPS IIIA program has complex and difficult work ahead as
it undertakes assembly, integration, and test efforts, and its
schedule may leave little margin to address challenges that may arise.
Such issues could affect the Air Force's ability to launch satellites
on time, which in turn may affect future GPS constellation
availability. Furthermore, because of continued delays with ground
control systems and the challenges the Air Force is encountering with
enabling quicker procurement of military GPS user equipment, new
capabilities may not be delivered to the warfighters when DOD needs
them. To better align key decisions and capability deliveries, DOD is
now looking more broadly across the GPS enterprise. However, it
remains to be seen whether these actions go far enough to synchronize
all GPS segments to the maximum extent practicable. For example, while
DOD's new Space and Intelligence Office will help ensure that the
development and acquisition of all GPS segments are synchronized, this
office does not have authority over all military user equipment
development. Consequently, we reiterate our recommendation from our
April 2009 report that the Secretary of Defense appoint a single
authority to oversee the development of GPS, including DOD space,
ground control, and user equipment assets, to ensure that the program
is well executed and resourced and that potential disruptions are
minimized. Furthermore, we specified that the appointee should have
the authority to ensure that all GPS segments are synchronized to the
maximum extent practicable, and should coordinate with the existing
PNT infrastructure to assess and minimize potential service
disruptions should the satellite constellation decrease in size for an
extended period of time. Regarding the GPS interagency requirements
process, there is still a great deal of confusion about how civil
agencies should submit and pay for their requirements. Moreover, this
year we found that a lack of comprehensive guidance on the GPS
interagency requirements process is a key source of this confusion.
Taking steps to clarify the process, documentation requirements, and
definitions of key terms would help alleviate this confusion.
Recommendation for Executive Action:
We recommend that the Secretaries of Defense and Transportation, whose
departments co-chair the National Executive Committee for Space-Based
Positioning, Navigation, and Timing, develop more comprehensive
guidance for the GPS interagency requirements process, including an
explanation of key terms, documentation expectations, process steps,
requirements approval, and funding commitments.
Agency Comments and Our Evaluation:
We provided a draft of this report to the Secretaries of Defense,
Commerce, Energy, Homeland Security, State, and Transportation and the
Administrator of the National Aeronautics and Space Administration for
comment. DOD provided written comments on a draft of this report that
are reprinted in appendix III. DOT provided oral comments on a draft
of this report.
In written comments, DOD did not concur with our recommendation that
the Secretary of Defense and the Secretary of Transportation develop
comprehensive guidance for the GPS interagency requirements process,
including an explanation of key terms, documentation expectations,
process steps, requirements approval, and funding commitments. DOD
stated that the actions being taken by IFOR to clarify existing
guidance, ranging from the new IFOR charter (signed in May 2010) to a
directed review of the IRP, meet the needs being recommended by the
report. DOT generally agreed to consider our recommendation.
The IFOR charter, which was updated on May 26, 2010, includes some
notable improvements compared to previous guidance, but it does not
address all of the shortcomings we identified. In particular, the
revised guidance provides more clarity regarding what documentation
should be provided with requirements proposal submissions; IFOR's role
in approving or rejecting proposed new requirements; and expectations
regarding funding commitments, including the timing of commitments. In
addition, the guidance states that requirements will be classified as
operational requirements or additional payloads; however, it does not
explain what the implications of those classifications are in terms of
how the requirements will be treated in the interagency requirements
process. The guidance also does not include definitions of civil
unique and dual-use requirements, yet there are ongoing deliberations
regarding whether SLR is a dual-use requirement. The revised guidance
also lacks information on the type of detail, level of detail, and
formatting structure for documentation required with requirements
proposal submissions. Lastly, the guidance does not specify how IFOR
approvals are to be documented and lacks specificity regarding at what
stage a requirement is officially approved for inclusion on GPS
satellites. Given that there is still confusion about how civil
agencies should submit and pay for their requirements, we believe our
recommendation remains valid that the Secretaries of Defense and
Transportation, who are responsible for leading interagency
coordination, should provide more comprehensive guidance.
DOD's written comments noted that DOD concurred with a "For Official
Use Only" (FOUO) designation for our report, which was its status
while in draft. We subsequently worked with DOD to identify and revise
specific areas of the report containing FOUO information, and DOD has
confirmed that this version of the report is acceptable for public
release.
We received technical comments from the Departments of Commerce,
Energy, State, and Transportation and the National Aeronautics and
Space Administration, which have been incorporated where appropriate.
As agreed with your offices, unless you publicly announce the contents
of this report earlier, we plan no further distribution until 7 days
from the report date. At that time, we will send copies of this report
to the appropriate congressional committees; the Secretaries of
Defense, Commerce, Energy, Homeland Security, State, and
Transportation; the Administrator of the National Aeronautics and
Space Administration; and other interested parties. The report also
will be available at no charge on the GAO Web site at [hyperlink,
http://www.gao.gov].
If you have any questions about this report or need additional
information, please contact me at (202) 512-4841 or chaplainc@gao.gov.
Contact points for our Offices of Congressional Relations and Public
Affairs may be found on the last page of this report. The major
contributors to this report are listed in appendix IV.
Signed by:
Cristina T. Chaplain:
Director:
Acquisition and Sourcing Management:
[End of section]
Appendix I: Scope and Methodology:
In order to assess the status of the U.S. Air Force's efforts to
develop and deliver new Global Positioning System (GPS) satellites,
the availability of the GPS constellation, and the potential impacts
on users if the constellation availability diminishes below its
committed level of performance, we performed several tasks. Our work
is based on the most current information available as of April 16,
2010.
To assess the status of the Department of Defense's (DOD) efforts to
develop and deliver new GPS satellites, we reviewed and analyzed
current program plans and documentation related to cost, requirements,
program direction, and acquisition and launch schedules. We also
interviewed officials from the Office of the Assistant Secretary of
Defense, Networks and Information Integration; the Office of the Under
Secretary of Defense for Acquisition, Technology and Logistics; the
Office of the Joint Chiefs of Staff; U.S. Strategic Command; the Air
Force Space Command; the Air Force Space and Missile Systems Center's
GPS Wing; the Air Force's 2nd Space Operations Squadron; and the Air
Staff. In addition, to assess the reliability of the GPS IIIA space
vehicle integrated master schedule, we reviewed 5 of 20 supporting
project schedules and compared those schedules with relevant best
practices as identified in our Cost Estimating and Assessment Guide.
[Footnote 24] The review period for the 5 schedules was from May 2008
to July 2009. These 5 schedules were selected because they make up the
bulk of the work and they are most critical to the production of the
GPS IIIA space vehicle. This analysis revealed the extent to which the
schedules reflected key estimating practices that are fundamental to
having a reliable schedule. In conducting this analysis, we
interviewed GPS Wing officials and contractor representatives to
discuss their use of best practices in creating the program's current
schedules.
To assess the availability of the GPS constellation, we did the
following:
* Interviewed officials from the Air Force Space and Missile Systems
Center GPS Wing, the Air Force Space Command, the Air Force's 2nd
Space Operations Squadron, and the Department of Energy's National
Nuclear Security Administration. To assess the risks that a delay in
the acquisition and fielding of GPS III satellites could result in the
U.S. government failing to meet its commitment to a 95 percent
probability of maintaining a constellation of 24 operational GPS
satellites, we obtained information from the Air Force predicting the
reliability of 79 GPS satellites--each of the 32 operational (on-
orbit) satellites, 44 future GPS satellites, and 3 residual
satellites--as a function of their time on orbit. Each satellite's
total reliability function defines the probability that the satellite
will still be operational (or in sufficient working order to be made
operational) at a given time in the future. This reliability function
is generated from the product of two cumulative reliability functions--
a wear out reliability function governed by the cumulative normal
distribution and a random reliability function governed by the
cumulative Weibull distribution.[Footnote 25] The reliability function
for a specific satellite is defined by a set of four parameters--two
that define the cumulative normal distribution and two that define the
cumulative Weibull distribution.
* Obtained two sets of reliability parameters for each of the 79
satellites. One set of parameters describes the reliability of the
satellites based on the "current management" approach--the Air Force's
efforts to actively manage satellite subsystems to reduce a
satellite's overall consumption of power. The second set of parameters
assumed use of a power management approach--shutting off the
satellite's second payload once the satellite is not expected to be
capable of generating enough power to support both the positioning,
navigation, and timing (PNT) mission and the set of missions supported
by the second payload. For each of the 44 unlaunched satellites, we
also obtained a parameter defining its probability of successful
launch and its scheduled launch date. The 44 unlaunched satellites
include 12 IIF satellites, 8 IIIA satellites, 8 IIIB satellites, and
16 IIIC satellites; launch of the final IIIC satellite is scheduled
for July 2025. Using this information, we generated overall
reliability functions for each of the 32 operational, 44 unlaunched,
and 3 residual satellites GPS satellites. We discussed with Air Force
and Aerospace Corporation representatives, in general terms, how each
satellite's normal and Weibull parameters were calculated. However, we
did not analyze any of the data used to calculate these parameters.
* Developed a Monte Carlo simulation[Footnote 26] using the
reliability function for each of the 32 operational and 44 unlaunched
GPS satellites to predict the probability that at least a given number
of satellites would be operational as a function of time, based on the
GPS launch schedule approved in December 2009.[Footnote 27] We
conducted several runs of our simulation--each run consisting of
10,000 trials--and generated curves depicting the predicted size of
the GPS constellation at the 95 percent confidence level as a function
of time. During last year's review, we compared the results for a 24-
satellite constellation with a similar Monte Carlo simulation that the
Aerospace Corporation had performed for the Air Force, and confirmed
that our simulation produced results that are very similar.[Footnote
28] We compared our results with the results for the predicted size of
the GPS constellation over time (at the 95 percent confidence level)
that we had calculated last year using the GPS reliability data and
launch schedule approved in March 2009. We then used our Monte Carlo
simulation model to examine the impact of a 2-year delay in the launch
of all GPS III satellites. We moved each GPS III launch date back by 2
years. We then reran the model and calculated a new curve for the size
of the operational constellation as a function of time.
To assess the military services' understanding of the potential
impacts on users if the constellation availability diminishes below
its committed level of performance, we asked Air Force, Army, Marine
Corps, and Navy military service user representatives to provide
formal studies and analyses regarding this issue. However, because
most military service representatives stated that their services had
not conducted formal studies and analyses on this issue, we also
obtained written responses to questions regarding this issue from the
military service representatives. In addition, to describe civil
departments' and agencies' understanding of the potential impacts on
users if the constellation availability diminishes below its committed
level of performance, we obtained written responses to questions
regarding this issue from civil departments and agencies involved with
the GPS interagency requirements process, including the National
Aeronautics and Space Administration; the Department of
Transportation, including the Federal Aviation Administration; the
Department of Commerce, including the National Oceanic and Atmospheric
Administration and the National Institute of Standards and Technology;
and the Department of Homeland Security, including the U.S. Coast
Guard.
To assess the progress of efforts to acquire the GPS ground control
and user equipment, we interviewed officials who manage and oversee
these acquisitions, including officials from the Office of the
Assistant Secretary of Defense, Networks and Information Integration;
the Office of the Under Secretary of Defense for Acquisition,
Technology and Logistics; the Office of the Joint Chiefs of Staff;
U.S. Strategic Command; the Air Force Space Command; the Air Force
Space and Missile Systems Center's GPS Wing; the Air Force's 2nd Space
Operations Squadron; and the Air Staff. We reviewed recent
documentation regarding the delivery of capabilities and equipment and
assessed the level of synchronization among satellites, ground
systems, and user equipment. Our work is based on the most current
information available as of April 16, 2010.
To assess the GPS interagency requirements process, we (1) reviewed
and analyzed guidance on the process and documents related to the
status of civil requirements and (2) interviewed officials from the
National Aeronautics and Space Administration; the Department of
Transportation, including the Federal Aviation Administration; the
Department of Commerce, including the National Oceanic and Atmospheric
Administration and the National Institute of Standards and Technology;
the Coast Guard; the Office of the Assistant Secretary of Defense,
Networks and Information Integration; the National Security Space
Office; the Air Force Space Command; the Interagency Forum for
Operational Requirements; and the National Coordination Office for
Space-Based Positioning, Navigation, and Timing. Our work is based on
the most current information available as of March 10, 2010.
To assess GPS coordination efforts with the international global PNT
community, we interviewed officials at the Department of State and the
Air Force Space and Missile Systems Center's GPS Wing and some
industry representatives. We also reviewed a July 2009 report to
Congress from the Office of the U.S. Trade Representative. Our work is
based on the most current information available as of March 2, 2010.
We conducted this performance audit from July 2009 to September 2010
in accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our
findings and conclusions based on our audit objectives. We believe
that the evidence obtained provides a reasonable basis for our
findings and conclusions based on our audit objectives.
[End of section]
Appendix II: GAO Assessment of GPS IIIA Prime Contractor Schedule
Management Processes:
Our research has identified nine practices associated with effective
schedule estimating[Footnote 29]: (1) capturing all activities, (2)
sequencing all activities, (3) assigning resources to all activities,
(4) establishing the duration of all activities, (5) integrating
schedule activities horizontally and vertically, (6) establishing the
critical path for all activities, (7) identifying float[Footnote 30]
between activities, (8) conducting a schedule risk analysis, and (9)
updating the schedule using logic and durations to determine the dates.
The GPS IIIA space vehicle integrated master schedule consists of a
master schedule with 20 embedded project schedules representing
individual integrated product teams. We selected 5 of these project
schedules for review because they make up the bulk of the work and
they are most critical to the production of the GPS IIIA space
vehicle. Specifically, we selected the Antenna Element, Bus, General
Dynamics, Navigation Unit Panel, and Launch Operations project
schedules and assessed them against the nine best practices for
schedule development (see table 4). The review period for the 5
schedules was from May 2008 to July 2009.
Table 4: Schedules and Their Descriptions:
Schedule name: Antenna Element;
Description: Represents the subcontractor integration effort for the
antenna element program that ensures the development, testing, and
qualification of the following antennas: navigation L-band (long-
frequency wave used in civil signals) antennas; the legacy ultra high-
frequency crosslink antenna; and telemetry, tracking, and control
antennas.
Schedule name: Bus;
Description: Represents the Lockheed Martin integration effort for the
design, development, fabrication, assembly, testing, and qualification
of the space vehicle bus and subsystems and units.
Schedule name: General Dynamics;
Description: Represents General Dynamic's effort as a subcontractor on
the communications portion.
Schedule name: Launch Operations;
Description: Represents the Lockheed Martin integration effort to
assess all facilities, communications, timelines, transportation, test
equipment, plans, and other capabilities for a successful launch
campaign.
Schedule name: Navigation Unit Panel;
Description: Represents the Lockheed Martin integration effort of
International Telephone and Telegraph subcontractor work (Mission Data
Unit time keeping, panel, program engineering, test equipment, and
transmitter subschedules).
Source: GAO analysis of Air Force GPS IIIA schedule data.
[End of table]
A well-defined schedule helps to identify the amount of human capital
and fiscal resources that are needed to execute the program, and thus
is an important contribution to a reliable cost estimate. Our research
has identified a range of best practices associated with effective
schedule estimating.[Footnote 31] These practices are as follows:
* Capturing all activities: The schedule should reflect all activities
(steps, events, outcomes, etc.) as defined in the program's work
breakdown structure, including activities to be performed by both the
government and its contractors.
* Sequencing all activities: The schedule should be planned so that it
can meet the program's critical dates. To meet this objective,
activities need to be logically sequenced in the order that they are
to be carried out. In particular, activities that must finish prior to
the start of other activities (i.e., predecessor activities) and
activities that cannot begin until other activities are completed
(i.e., successor activities) should be identified. By doing so,
interdependencies among activities that collectively lead to the
accomplishment of events or milestones can be established and used as
a basis for guiding work and measuring progress.
* Assigning resources to all activities: The schedule should
realistically reflect what resources (i.e., labor, material, and
overhead) are needed to do the work, whether all required resources
will be available when they are needed, and whether any funding or
time constraints exist.
* Establishing the duration of all activities: The schedule should
reflect how long each activity will take to execute. In determining
the duration of each activity, the same rationale, data, and
assumptions used for cost estimating should be used for schedule
estimating. Further, these durations should be as short as possible
and they should have specific start and end dates. Excessively long
periods needed to execute an activity should prompt further
decomposition of the activity so that shorter execution durations will
result.
* Integrating schedule activities horizontally and vertically: The
schedule should be horizontally integrated, meaning that it should
link the products and outcomes associated with already sequenced
activities. These links are commonly referred to as handoffs and serve
to verify that activities are arranged in the right order to achieve
aggregated products or outcomes. The schedule should also be
vertically integrated, meaning that traceability exists among varying
levels of activities and supporting tasks and subtasks. Such mapping
or alignment among levels enables different groups to work to the same
master schedule.
* Establishing the critical path for all activities: Using scheduling
software the critical path--the longest duration path through the
sequenced list of activities--should be identified. The establishment
of a program's critical path is necessary for examining the effects of
any activity slipping along this path. Potential problems that may
occur on or near the critical path should also be identified and
reflected in the scheduling of time for high-risk activities.
* Identifying float between activities: The schedule should identify
float--the time that a predecessor activity can slip before the delay
affects successor activities--so that schedule flexibility can be
determined. As a general rule, activities along the critical path have
the least amount of float.
* Conducting a schedule risk analysis: A schedule risk analysis uses a
good critical path method schedule and data about project schedule
risks as well as Monte Carlo simulation (statistical) techniques to
predict the level of confidence in meeting a program's completion
date, the amount of time needed for a level of confidence, and the
identification of high-priority risks. This analysis focuses not only
on critical path activities but also on other schedule paths that may
become critical. A schedule/cost risk assessment recognizes the
interrelationship between schedule and cost and captures the risk that
schedule durations and cost estimates may vary because of, among other
things, limited data, optimistic estimating, technical challenges,
lack of qualified personnel, and other external factors. As a result,
the baseline schedule should include a buffer or a reserve of extra
time. Schedule reserve for contingencies should be calculated by
performing a schedule risk analysis. As a general rule, the reserve
should be held by the project manager and applied as needed to those
activities that take longer than scheduled because of the identified
risks. Reserves of time should not be apportioned in advance to any
specific activity since the risks that will actually occur and the
magnitude of their impact is not known.
* Updating the schedule using logic and durations to determine the
dates: The schedule should use logic and durations in order to reflect
realistic start and completion dates for program activities. The
schedule should be continually monitored to determine when forecasted
completion dates differ from the planned dates, which can be used to
determine whether schedule variances will affect downstream work.
Maintaining the integrity of the schedule logic is not only necessary
to reflect true status, but is also required before conducting a
schedule risk analysis. The schedule should avoid logic overrides and
artificial constraint dates that are chosen to create a certain result
on paper. To ensure that the schedule is properly updated, individuals
trained in critical path method scheduling should be responsible for
updating the schedule.
Table 5 presents the findings for the five project schedules for each
best practice, along with an overall score for the integrated master
schedule on each best practice. Tables 6 through 10 provide details on
the individual project schedule assessments. All durations are given
in working time, that is, there are 5 working days per week, 22
working days per month, and 260 working days per year.
Table 5: Extent to Which Each Project Schedule Met Best Practices:
Best practice: 1. Capturing all activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Met;
Antenna: Met;
Bus: Met;
General Dynamics: Met;
Navigation unit panel: Substantially met;
Launch operations: Met.
Best practice: 2. Sequencing all activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Substantially met;
Antenna: Substantially met;
Bus: Substantially met;
General Dynamics: Partially met;
Navigation unit panel: Partially met;
Launch operations: Substantially met.
Best practice: 3. Assigning resources to all activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Met;
Antenna: Met;
Bus: Met;
General Dynamics: Met;
Navigation unit panel: Met;
Launch operations: Substantially met.
Best practice: 4. Establishing the duration of all activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Substantially met;
Antenna: Substantially met;
Bus: Substantially met;
General Dynamics: Substantially met;
Navigation unit panel: Substantially met;
Launch operations: Substantially met.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Substantially met;
Antenna: Substantially met;
Bus: Substantially met;
General Dynamics: Substantially met;
Navigation unit panel: Substantially met;
Launch operations: Substantially met.
Best practice: 6. Establishing the critical path for all activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Substantially met;
Antenna: Substantially met;
Bus: Met;
General Dynamics: Substantially met;
Navigation unit panel: Substantially met;
Launch operations: Met.
Best practice: 7. Identifying float between activities;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Partially met;
Antenna: Partially met;
Bus: Partially met;
General Dynamics: Partially met;
Navigation unit panel: Partially met;
Launch operations: Partially met.
Best practice: 8. Conducting a schedule risk analysis;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Met;
Antenna: Met;
Bus: Met;
General Dynamics: Met;
Navigation unit panel: Partially met;
Launch operations: Substantially met.
Best practice: 9. Updating the schedule using logic and durations to
determine dates;
Overall assessment (met, substantially met, partially met, minimally
met, not met)[A]: Met;
Antenna: Substantially met;
Bus: Substantially met;
General Dynamics: Met;
Navigation unit panel: Met;
Launch operations: Met.
Source: GAO analysis of Air Force GPS IIIA schedule data.
[A] Based on our analysis of the schedules and discussions with the
GPS IIIA contractor, we rated each schedule against our five-point
criteria and assigned a corresponding score using the evidence
provided to support our ratings: met = 5, substantially met = 4,
partially met =3, minimally met = 2, and not met = 1. Met--DOD
provided complete evidence that satisfies the entire criterion.
Substantially met--DOD provided evidence that satisfies more than half
of the criterion. Partially met--DOD provided evidence that satisfies
about half of the criterion. Minimally met--DOD provided evidence that
satisfies less than half of the criterion. Not met--DOD provided no
evidence that satisfies any part of the criterion.
[End of table]
Table 6: Antenna Element Schedule Analysis Details:
Best practice: 1.Capturing all activities;
Criterion met? Met;
GAO analysis: Activities in the GPS IIIA integrated master schedule
are mapped to Integrated Master Plan (IMP), Statement of Work (SOW),
Contractor Work Breakdown Structure (CWBS), and Control Account
Manager (CAM) custom fields. The activities in the Antenna schedule
are mapped to 18 different SOW numbers. CAMs are involved in
developing the schedule and revising activities within the schedule as
necessary.
Best practice: 2. Sequencing all activities;
Criterion met? Substantially met;
GAO analysis: Our analysis shows that none of the 554 remaining
activities have missing logic. Of those remaining activities that have
predecessor and successor logic, only 3 activities are "open-ended,"
that is, 3 activities are missing logic that would determine their
start dates. Because their start dates are not determined by logic,
these 3 open-ended activities may inhibit the power of the schedule to
calculate a critical path and important downstream dates. We found
that the schedule uses many constraints, particularly Start No Earlier
Than (SNET) constraints. There are 71 remaining activities (13
percent) with SNET constraints. Program schedule officials stated that
the SNET constraints are used to manage resources and to schedule
procurement tasks to start once funding is available. However,
constraining an activity's start date prevents managers from
accomplishing work as soon as possible and consumes flexibility early
in the project. Moreover, scheduling a procurement activity with a
constrained date does not guarantee that the item will arrive on that
date in reality. Of the remaining activities, 35 activities (6
percent) are linked to their successor activities with lags. Lags are
often used to put activities on a specific date or to insert a buffer
for risk; however, these lags persist even when predecessor activities
are delayed (that is, when the buffer should be consumed).
Best practice: 3. Assigning resources to all activities;
Criterion met? Met;
GAO analysis: We found the schedule to be sufficiently resource
loaded. There are 53 resources listed in the schedule; two are
specifically applied to the Antenna schedule activities with no
evidence of overallocation. GPS Wing officials also indicated that the
CAMs use the schedule along with other tools to review and plan for
resource usage.
Best practice: 4. Establishing the duration of all activities;
Criterion met? Substantially met;
GAO analysis: The durations of the majority of remaining activities
meet best practices. However, several activities have longer-than-
expected[A] durations. For example, 28 remaining activities have
durations over 200 days. Several of these activities are long-lead
item procurement activities that may need alternative ways to monitor
their progress. GPS Wing officials stated that CAMs review and monitor
activity durations.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Criterion met? Substantially met;
GAO analysis: Our analysis of the schedule concludes that vertical
traceability--that is, the ability to consistently trace Work
Breakdown Structure (WBS) elements between detailed, intermediate, and
master schedules--is demonstrated because the overall GPS IIIA
integrated master schedule is made up of individual subschedules like
the Antenna schedule. However, issues with reliance on date
constraints and the use of lags keep this detailed schedule from being
fully compliant with the requirement of horizontal traceability--that
is, the overall ability of the schedule to depict relationships
between different program elements and product handoffs.
Best practice: 6. Establishing the critical path for all activities;
Criterion met? Substantially met;
GAO analysis: We discussed with GPS Wing officials how the critical
path is calculated in the Antenna schedule. The Antenna critical path
contains a 20-day margin for risk, which is considered a good practice
as this represents an acknowledgment of inherent risk within the
schedule. However, our analysis also shows that there are lags of 130
days and 40 days in the critical path, and the first activity of the
path starts with an unjustified SNET constraint. The critical path
should determine the project completion date by computation using the
logical relations between predecessor activities and their durations
rather than artificial constraints.
Best practice: 7. Identifying realistic total float;
Criterion met? Partially met;
GAO analysis: There are 31 activities with over 400 days of total
float, and 211 activities with from 200 to 399 days of total float. In
other words, according to the schedule, 242 activities could be
delayed by 9 to 18 months and not delay the final activity in the
Antenna schedule. Activities with such large float values indicate
some lack of completeness in the schedule logic.
Best practice: 8. Conducting a schedule risk analysis;
Criterion met? Met;
GAO analysis: GPS Wing officials provided evidence of a risk analysis
being done on the entire integrated master schedule. The program uses
traditional risk ranges of minimum, most likely, and high, which are
applied to activity durations. The ranges are applied to triangular
distributions before Monte Carlo simulations. In the Antenna schedule,
we found 421 activities that have reasonable risk ranges for their
durations that follow the guidance provided by the program. Note that
there is no need to put risk ranges on every detail task to have a
successful risk analysis. GPS Wing officials told us that risk
analysis is run on the schedule monthly.
Best practice: 9. Updating the schedule using logic and durations to
determine the dates;
Criterion met? Substantially met;
GAO analysis: There are only seven instances of out-of-sequence logic--
that is, actual progress being recorded on successor activities even
though the predecessor activities are not complete. This is a common
occurrence in scheduling, as reality often overrides planned logic.
However, some of the schedule logic appears to have been initially
incorrect as some of the successor activities have started almost 2
years early. Some of these successors are in other detailed schedules
and cannot be moved by the Antenna schedule.
Source: GAO analysis of Air Force GPS IIIA Antenna element schedule
data.
[A] The Defense Contract Management Agency recommends keeping
individual task durations to less than 2 calendar months (or 44
working days). The shorter the duration of the tasks in the schedule,
the more often the CAMs are compelled to update completed work, which
more accurately reflects the actual status of the tasks. When task
durations are very long, management insight into the actual status is
decreased.
[End of table]
Table 7: Bus Schedule Analysis Details:
Best practice: 1. Capturing all activities;
Criterion met? Met;
GAO analysis: Activities in the GPS IIIA integrated master schedule
are mapped to IMP, SOW, CWBS, and CAM custom fields. There are 100 out
of the remaining 2,082 activities that do not have SOW numbers, but
these are mostly zero-duration milestones, and one is a general delay
task. CAMs are involved in developing the schedule and revise
activities within the schedule as necessary.
Best practice: 2. Sequencing all activities;
Criterion met? Substantially met;
GAO analysis: Our analysis shows that none of the 2,082 remaining
activities have missing logic. Of those remaining activities that have
predecessor and successor logic, only 5 activities are "open-ended"--
that is, 5 activities are missing logic from their finish dates that
would determine the start dates of their successors. Because their
finish dates do not link to the start dates of successor activities,
these 5 open-ended activities will not affect the start dates of any
successors if they are delayed. In addition, these open-ended
activities can create artificially large total float values, which may
affect management's ability to effectively allocate resources. We
found that the schedule uses many constraints, particularly SNET
constraints. There are 270 remaining activities (13 percent) with
constraints, 269 of which are SNET constraints. Program schedule
officials stated that the SNET constraints are used to manage
resources and to schedule procurement tasks to start once funding is
available. However, constraining an activity's start date prevents
managers from accomplishing work as soon as possible and consumes
flexibility early in the project. Moreover, scheduling a procurement
activity with a constrained date does not guarantee that the item will
arrive on that date in reality. Of the remaining activities, 63
activities (3 percent) are linked to their successor activities with
lags. Lags are often used to put activities on a specific date or to
insert a buffer for risk; however, these lags persist even when
predecessor activities are delayed (that is, when the buffer should be
consumed).
Best practice: 3. Assigning resources to all activities;
Criterion met? Met;
GAO analysis: We found the schedule to be sufficiently resource
loaded. There are 14 main resources listed in the Bus schedule that
have been used in over 2,000 activity assignments. There is no
evidence of overallocation. GPS Wing officials also indicated that the
CAMs use the schedule along with other tools to review and plan for
resource usage.
Best practice: 4. Establishing the duration of all activities;
Criterion met? Substantially met;
GAO analysis: The durations of the majority of remaining activities
meet best practices. However, several activities have longer-than-
expected durations. For example, 7 remaining activities have durations
over 400 days, and 106 have durations from 200 to 400 days. The
longest duration is that of the battery cell life test, which takes 7-
½ years. It will be difficult to update such an activity unless the
activity is split up into more manageable parts. GPS Wing officials
stated that CAMs review and monitor activity durations.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Criterion met? Substantially met;
GAO analysis: Our analysis of the schedule concludes that vertical
traceability--that is, the ability to consistently trace WBS elements
between detailed, intermediate, and master schedules--is demonstrated
because the overall GPS IIIA integrated master schedule is made up of
individual subschedules like the Bus schedule. However, issues with
reliance on date constraints and the use of lags keep this detailed
schedule from being fully compliant with the requirement of horizontal
traceability--that is, the overall ability of the schedule to depict
relationships between different program elements and product handoffs.
Best practice: 6. Establishing the critical path for all activities;
Criterion met? Met;
GAO analysis: We discussed with GPS Wing officials how the critical
path is calculated in the Bus schedule. Only six activities in the Bus
schedule are on the critical path and hence determine the date for
SV01 Satellite Delivery. This is a consequence of a highly integrated
master schedule with 20 component schedules.
Best practice: 7. Identifying realistic total float;
Criterion met? Partially met;
GAO analysis: There are 50 activities with over 600 days of total
float, and 303 activities with from 300 to 600 days of total float. In
other words, according to the schedule, 353 activities could be
delayed by 14 to 27 months and not delay the final activity in the Bus
schedule. These high float values are due to incomplete logic and
reliance on constraints instead of logic and durations to drive this
schedule. Activities with such large float values indicate some lack
of completeness in the schedule logic.
Best practice: 8. Conducting a schedule risk analysis;
Criterion met? Met;
GAO analysis: GPS Wing officials provided evidence of a risk analysis
being done on the entire integrated master schedule. In the Bus
schedule, we found 1,109 activities that have reasonable risk ranges
about their durations. Note that there is no need to put risk ranges
on every detail task to have a successful risk analysis. These ranges
are mostly percentages around the durations and are right-skewed to
convey a higher probability of running longer than running shorter--a
common technique in risk analysis. GPS Wing officials told us that
risk analysis is run on the schedule monthly.
Best practice: 9. Updating the schedule using logic and durations to
determine the dates;
Criterion met? Substantially met;
GAO analysis: There are 13 instances of out-of-sequence logic--that
is, actual progress being recorded on successor activities even though
the predecessor activities are not complete. This is a common
occurrence in scheduling, as reality often overrides planned logic.
However, some of the schedule logic shows successors that were
completed in earlier years, which should be corrected. Without
complete, up-to-date logic, the critical path and important dates
downstream may be incorrect.
Source: GAO analysis of Air Force GPS IIIA Bus schedule data.
[End of table]
Table 8: General Dynamics Schedule Analysis Details:
Best practice: 1. Capturing all activities;
Criterion met? Met;
GAO analysis: Activities in the GPS IIIA integrated master schedule
are mapped to IMP, SOW, CWBS, and CAM custom fields. There are 15 out
of the remaining 1,922 activities that do not have SOW numbers. CAMs
are involved in developing the schedule and revise activities within
the schedule as necessary.
Best practice: 2. Sequencing all activities;
Criterion met? Partially met;
GAO analysis: Our analysis shows that 43 of the 1,922 remaining
activities (2 percent) are "open-ended." Of these, 42 activities are
missing logic from their finish dates that would determine the start
dates of their successors. Because their finish dates do not link to
the start dates of successor activities, these 42 open-ended
activities will not affect the start dates of any successors if they
are delayed. In addition, these open-ended activities can create
artificially large total float values, which may affect management's
ability to effectively allocate resources. We found that the schedule
uses many constraints, particularly SNET constraints. There are 416
remaining 1,922 activities (22 percent) with constraints, 382 of which
are SNET constraints. Program schedule officials stated that the SNET
constraints are used to manage resources and to schedule procurement
tasks to start once funding is available. However, constraining an
activity's start date prevents managers from accomplishing work as
soon as possible and consumes flexibility early in the project.
Moreover, scheduling a procurement activity with a constrained date
does not guarantee that the item will arrive on that date in reality.
The 416 constraints within the schedule include 27 Finish No Earlier
Than (FNET) constraints. Each FNET constraint needs to be examined and
justified, as such constraints prevent an activity from finishing
earlier if predecessor activities allow it. Of the remaining
activities, 167 activities (9 percent) are linked to their successor
activities with lags. Lags are often used to put activities on a
specific date or to insert a buffer for risk; however, these lags
persist even when predecessor activities are delayed (that is, when
the buffer should be consumed).
Best practice: 3. Assigning resources to all activities;
Criterion met? Met;
GAO analysis: We found the schedule to be sufficiently resource
loaded. There are 92 resources listed in the General Dynamics schedule
that are named, costed, and assigned to activities. GPS Wing officials
also indicated that the CAMs use the schedule along with other tools
to review and plan for resource usage.
Best practice: 4. Establishing the duration of all activities;
Criterion met? Substantially met;
GAO analysis: The durations of the majority of remaining activities
meet best practices. However, several activities have longer-than-
expected durations (i.e., durations of no more than 2 months). For
example, 26 remaining activities have durations from 300 to 780 days,
and 102 have durations from 100 to 300 days. There are 10 activities
with durations greater than 700 days, all of which appear to be level-
of-effort activities. However, these durations are fixed, so that if
the activities that they support take more or less time, the level of
effort does not change durations as it should.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Criterion met? Substantially met;
GAO analysis: Our analysis of the schedule concludes that vertical
traceability--that is, the ability to consistently trace WBS elements
between detailed, intermediate, and master schedules--is demonstrated
because the overall GPS IIIA integrated master schedule is made up of
individual subschedules like the General Dynamics schedule. However,
issues with reliance on date constraints and the use of lags keep this
detailed schedule from being fully compliant with the requirement of
horizontal traceability--that is, the overall ability of the schedule
to depict relationships between different program elements and product
handoffs.
Best practice: 6. Establishing the critical path for all activities;
Criterion met? Substantially met;
GAO analysis: We discussed with GPS Wing officials how the critical
path is calculated in the General Dynamics schedule. Our analysis of
the critical path shows that while it is determined by predecessor
logic and durations rather than constraints, it includes two
unexplained lags of 77 total days. It is not clear why the program
should choose to delay the start of the lagged activities that occur
on the critical path by a total of 15 weeks.
Best practice: 7. Identifying realistic total float;
Criterion met? Partially met;
GAO analysis: There are 1,079 remaining activities (56 percent) with
100 or more days of total float, 25 of which have from 700 to 771 days
of total float. In other words, according to the schedule, 25
activities could be delayed by almost 32 months and not delay the
final activity in the General Dynamics schedule. These high float
values are due to incomplete logic and reliance on constraints instead
of logic and durations to drive this schedule. Activities with such
large float values indicate some lack of completeness in the schedule
logic.
Best practice: 8. Conducting a schedule risk analysis;
Criterion met? Met;
GAO analysis: GPS Wing officials provided evidence of a risk analysis
being done on the entire integrated master schedule. The program uses
traditional risk ranges of minimum, most likely, and high, which are
applied to activity durations. The ranges are applied to triangular
distributions before Monte Carlo simulations are run. In the General
Dynamics schedule, we found 1,758 activities that have reasonable risk
ranges about their durations. These ranges are mostly percentages
around the durations and are right-skewed to convey a higher
probability of running longer than running shorter--a common technique
in risk analysis. GPS Wing officials told us that risk analysis is run
on the schedule monthly.
Best practice: 9. Updating the schedule using logic and durations to
determine the dates;
Criterion met? Met;
GAO analysis: Our analysis shows that there are no instances of out-of-
sequence logic--that is, actual progress being recorded on successor
activities even though the predecessor activities are not complete.
Our analysis found no instances of actual dates in the future or dates
in the past that are not marked as "actual."
Source: GAO analysis of Air Force GPS IIIA General Dynamics schedule
data.
[End of table]
Table 9: Navigation Unit Panel Schedule Analysis Details:
Best practice: 1. Capturing all activities;
Criterion met? Substantially met;
GAO analysis: Activities in the GPS IIIA integrated master schedule
are designed to be mapped to IMP, SOW, CWBS, and CAM information. CAMs
are involved in developing the schedule and revise activities within
the schedule as necessary. However, officials stated that while the
Panel schedule was verified by the prime contractor to fully support
the SOW, the SOW data were inadvertently overwritten with other data.
Senior schedulers are currently in the process of repopulating the SOW
information in the Panel schedule.
Best practice: 2. Sequencing all activities;
Criterion met? Partially met;
GAO analysis: Our analysis shows that 9 of the 126 remaining
activities (7 percent) are "open-ended." These 9 open-ended activities
are missing logic from their finish dates that would determine the
start dates of their successors. Because their finish dates do not
link to the start dates of successor activities, these 9 open-ended
activities will not affect the start dates of any successors if they
are delayed. In addition, these open-ended activities can create
artificially large total float values, which may affect management's
ability to effectively allocate resources. Considering that there are
only 95 remaining detail activities (the other 31 remaining activities
are milestones), this means that nearly 10 percent of the remaining
work activities are not properly linked. We found the schedule uses
many constraints, particularly SNET constraints. There are 12 SNET
constraints placed on activities within the schedule, of which 11
activities are imported from other schedules within the integrated
master schedule. These 11 activities would presumably have their dates
established in their own schedules by logic and duration, and
therefore should not need constraining in the Panel schedule. There
are 15 activities with lags to their successor activities. Lags are
often used to put activities on a specific date or to insert a buffer
for risk; however, these lags persist even when predecessor activities
are delayed (that is, when the buffer should be consumed).
Best practice: 3. Assigning resources to all activities;
Criterion met? Met;
GAO analysis: We found the schedule to be sufficiently resource
loaded. There are 18 resources listed in the Panel schedule, several
of which have been applied extensively to the schedule. GPS Wing
officials also indicated that the CAMs use the schedule along with
other tools to review and plan for resource usage.
Best practice: 4. Establishing the duration of all activities;
Criterion met? Substantially met;
GAO analysis: The durations of the majority of remaining activities
meet best practices. However, several activities have longer-than-
expected durations (i.e., durations of no more than 2 months). For
example, 13 remaining activities have durations from 200 to 540 days,
and 13 have durations from 45 to 199 days. It will be difficult to
update long, non-level-of-effort activities unless the activities are
split up into more manageable parts. GPS Wing officials stated that
CAMs review and monitor activity durations.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Criterion met? Substantially met;
GAO analysis: Our analysis of the schedule concludes that vertical
traceability--that is, the ability to consistently trace WBS elements
between detailed, intermediate, and master schedules--is demonstrated
because the overall GPS IIIA integrated master schedule is made up of
individual subschedules like the Panel schedule. However, issues with
reliance on date constraints and the use of lags keep this detailed
schedule from being fully compliant with the requirement of horizontal
traceability--that is, the overall ability of the schedule to depict
relationships between different program elements and product handoffs.
Best practice: 6. Establishing the critical path for all activities;
Criterion met? Substantially met;
GAO analysis: We discussed with GPS Wing officials how the critical
path is calculated in the Panel schedule. Our analysis of the critical
path shows that while it is determined by predecessor logic and
durations rather than constraints, it includes two unexplained lags of
26 total days. While these are not large lags, it is not clear why the
program should choose to delay the start of events on the critical
path by over 5 weeks.
Best practice: 7. Identifying realistic total float;
Criterion met? Partially met;
GAO analysis: There are 31 activities within the schedule with 400 or
more days of total float, 18 of which have more than 1,000 days of
total float. In other words, according to the schedule, 31 activities
could be delayed by more than 1-½ years and not delay the final
activity in the Panel schedule. These high float values are due to
incomplete logic and reliance on constraints instead of logic and
durations to drive this schedule.
Best practice: 8. Conducting a schedule risk analysis;
Criterion met? Partially met;
GAO analysis: GPS Wing officials provided evidence of a risk analysis
being done on the entire integrated master schedule. However, our
analysis of the Panel schedule reveals that only two short tasks have
meaningful risk ranges. No other tasks within the schedule have risk
ranges. Therefore, the Panel schedule is not fully contributing to the
overall integrated master schedule risk analysis. Our analysis
indicates that some activities, by their descriptive names alone, seem
probable candidates for risk analysis. These include activities such
as "Test Flight ...," "Test on ...," "Verify ...," "Assembly ...," and
"Final Functional Test ...." Without conducting a comprehensive
schedule risk analysis, decision makers will not know in advance which
risks might delay the project, what a safe completion date might be
for the current plan, and how much contingency reserve of time may be
needed to achieve a successful completion date.
Best practice: 9. Updating the schedule using logic and durations to
determine the dates;
Criterion met? Met;
GAO analysis: Our analysis shows that there is only one instance of
out-of-sequence logic--that is, actual progress being recorded on
successor activities even though the predecessor is not complete. This
is a common occurrence in scheduling, as reality often overrides
planned logic. Our analysis found no instances of actual dates in the
future or dates in the past that are not marked as "actual."
Source: GAO analysis of Air Force GPS IIIA Navigation Unit Panel
schedule data.
[End of table]
Table 10: Launch Operations Schedule Analysis Details:
Best practice: 1. Capturing all activities;
Criterion met? Met;
GAO analysis: Activities in the GPS IIIA integrated master schedule
are designed to be mapped to IMP, SOW, CWBS, and CAM information. CAMs
are involved in developing the schedule and revise activities within
the schedule as necessary. All 382 remaining detail activities are
assigned to one of nine SOW numbers within the schedule.
Best practice: 2. Sequencing all activities;
Criterion met? Partially met;
GAO analysis: Our analysis shows that only 1 of the 497 remaining
activities is "open-ended." This open-ended activity is missing logic
that would determine its start date. Because its start date is not
determined by logic, this open-ended activity may inhibit the power of
the schedule to calculate a critical path and important downstream
dates. We found that the schedule uses many constraints, particularly
SNET constraints. There are 57 SNET constraints placed on activities
within the schedule. Program schedule officials stated that the SNET
constraints are used to manage resources and to schedule procurement
tasks to start once funding is available. However, constraining an
activity's start date prevents managers from accomplishing work as
soon as possible and consumes flexibility early in the project.
Moreover, scheduling a procurement activity with a constrained date
does not guarantee that the item will arrive on that date in reality.
There are 14 activities with lags to their successor activities. Some
lags are extremely long, ranging from 540 to 850 days. Lags are often
used to put activities on a specific date or to insert a buffer for
risk; however, these lags persist even when predecessor activities are
delayed (that is, when the buffer should be consumed). Extremely long
lags are usually used to force successor tasks to occur on specific
dates.
Best practice: 3. Assigning resources to all activities;
Criterion met? Substantially met;
GAO analysis: We found only one resource in the schedule, which was
assigned to 272 of 382 detail activities. GPS Wing officials indicated
that the CAMs use the schedule along with other tools to review and
plan for resource usage.
Best practice: 4. Establishing the duration of all activities;
Criterion met? Substantially met;
GAO analysis: The durations of the majority of remaining activities
meet best practices. However, several activities have longer-than-
expected durations (i.e., durations of no more than 2 months). For
example, 34 remaining activities have durations from 45 to 99 days,
and 5 have durations from 200 to 281 days. It will be difficult to
update long, non-level-of-effort activities unless the activities are
split up into more manageable parts. GPS Wing officials stated that
CAMs review and monitor activity durations.
Best practice: 5. Integrating schedule activities horizontally and
vertically;
Criterion met? Substantially met;
GAO analysis: Our analysis of the schedule concludes that vertical
traceability--that is, the ability to consistently trace WBS elements
between detailed, intermediate, and master schedules--is demonstrated
because the overall GPS IIIA integrated master schedule is made up of
individual subschedules like the Launch operations schedule. However,
issues with reliance on date constraints and the use of lags keep this
detailed schedule from being fully compliant with the requirement of
horizontal traceability--that is, the overall ability of the schedule
to depict relationships between different program elements and product
handoffs.
Best practice: 6. Establishing the critical path for all activities;
Criterion met? Met;
GAO analysis: We discussed with GPS Wing officials how the critical
path is calculated in the Launch schedule. The critical path in the
Launch schedule is less than 90 days. It begins with an external
activity, which is the result of extensive linkage between schedules
in the GPS IIIA integrated master schedule.
Best practice: 7. Identifying realistic total float;
Criterion met? Partially met;
GAO analysis: There are 111 activities within the schedule with 200 or
more days of total float, 33 of which have from 500 to 900 days of
total float. In other words, according to the schedule, 33 activities
could be delayed by over 22 months and not delay the final activity in
the Launch schedule. These high float values are due to incomplete
logic and reliance on constraints instead of logic and durations to
drive this schedule.
Best practice: 8. Conducting a schedule risk analysis;
Criterion met? Substantially met;
GAO analysis: GPS Wing officials provided evidence of a risk analysis
being done on the entire integrated master schedule. Our analysis of
the Launch schedule shows that 271 of 382 detail activities have risk
applied to them. However, all 271 activities have the same risk
applied to their durations. Therefore, it is difficult to determine
whether the Launch schedule is fully or meaningfully contributing to
the overall integrated master schedule risk analysis. Without
conducting a comprehensive schedule risk analysis, decision makers
will not know in advance which risks might delay the project, what a
safe completion date might be for the current plan, and how much
contingency reserve of time may be needed to achieve a successful
completion date.
Best practice: 9. Updating the schedule using logic and durations to
determine the dates;
Criterion met? Met;
GAO analysis: Our analysis shows that there are only two instances of
out-of-sequence logic--that is, actual progress being recorded on
successor activities even though the predecessor activities are not
complete. This is a common occurrence in scheduling, as reality often
overrides planned logic. Our analysis found no instances of actual
dates in the future or dates in the past that are not marked as
"actual."
Source: GAO analysis of Air Force GPS IIIA Launch Operations schedule
data.
[End of table]
[End of section]
Appendix III: Comments from the Department of Defense:
Office Of The Assistant Secretary Of Defense:
Networks And Information Integration:
6000 Defense Pentagon:
Washington, DC 20301-6000:
July 26, 2010:
Ms. Christina Chaplain:
Director, Acquisition and Sourcing Management:
U.S. Government Accountability Office (GAO):
441 G Street, NW:
Washington, DC 20548:
Dear Ms. Chaplain:
This is the Department of Defense (DoD) response to the GAO draft
report, GAO-10-636, "Global Positioning System: Challenges in
Sustaining and Upgrading Capabilities Persist," dated May 28, 2010
(GAO Code 120847).
The Department non-concurs with the recommendation that the Secretary
of Defense and Secretary of Transportation develop comprehensive
guidance for the GPS interagency requirements process. The actions
being taken by the Interagency Forum for Operational Requirements
(IFOR) to clarify existing guidance, ranging from the new IFOR Charter
(signed May 2010) to a directed review of the GPS Interagency
Requirements Plan (IRP), meet the needs being recommended by the
report. The Department also concurs with the "For Official Use Only"
designation of the subject report, with limited public release. [Note:
FOUO designation was removed during subsequent review and discussion
(see p. 40)]
Since its inception over 30 years ago, GPS has become one of the most
widely used systems in the world for military and civilian
Positioning, Navigation and Timing (PNT) purposes and sets the example
for other nations seeking to provide similar services. GPS enables
national security and economic infrastructures, which enhances
efficiency and improves safety and effectiveness of virtually all
operations. GPS is the cornerstone of our National PNT Architecture,
around which future PNT services will evolve. The DoD accepts its
responsibility with respect to GPS and is committed to maintaining and
improving the services it provides. In that regard, the Department
seeks support from Congress to maintain stability of GPS funding,
enabling synchronized modernization of GPS space, ground control, and
user equipment that is now underway.
The staff point of contact for this review is Mr. Raymond Swider. He
can be reached at raymond.swider@osd.mil or (703) 607-1122.
Signed by:
Dr. Ronald Jost:
Deputy Assistant Secretary of Defense (C3, Space & Spectrum)
[End of section]
Appendix IV: GAO Contact and Staff Acknowledgments:
GAO Contact:
Cristina Chaplain (202) 512-4841 or chaplainc@gao.gov:
Staff Acknowledgments:
In addition to the contact named above, key contributors to this
report were Art Gallegos, Assistant Director; Greg Campbell; Tisha
Derricotte; Steven Hernandez; Laura Holliday; Jason Lee; Sigrid
McGinty; Karen Richey; Jay Tallon; Hai Tran; Alyssa Weir; and Rebecca
Wilson.
[End of section]
Footnotes:
[1] GAO, Global Positioning System: Significant Challenges in
Sustaining and Upgrading Widely Used Capabilities, [hyperlink,
http://www.gao.gov/products/GAO-09-325] (Washington, D.C.: Apr. 30,
2009).
[2] GPS is augmented by ground-based or space-based navigation aids
that are maintained by individual departments and agencies to provide
users with improvements to the GPS navigation signal in terms of
accuracy, availability, and integrity needs.
[3] [hyperlink, http://www.gao.gov/products/GAO-09-325].
[4] On July 31, 2004, the Air Force GPS program office became the GPS
Wing, when the Air Force's Space and Missile Systems Center
reorganized and renamed its organizations to mirror the traditional
Air Force structure.
[5] The "back to basics" policy was instituted by the Air Force in
2007 to direct space programs to adopt acquisition practices such as
incremental introduction of new technologies to constellations of
satellites and stabilization of requirements early in the acquisition
process.
[6] Earned value management (EVM) is a program management tool that
integrates the technical, cost, and schedule parameters of a contract.
During the planning phase, an integrated baseline is developed by time-
phasing budget resources for defined work. As work is performed and
measured against the baseline, the corresponding budget value is
"earned." Using this earned value metric, cost and schedule variances
can be determined and analyzed. EVM provides significant benefits to
both the government and the contractor.
[7] GAO, Space Acquisitions: DOD Poised to Enhance Space Capabilities,
but Persistent Challenges Remain in Developing Space Systems,
[hyperlink, http://www.gao.gov/products/GAO-10-447T] (Washington,
D.C.: Mar. 10, 2010).
[8] A block, or increment, delivers a capability in a discrete, value-
added increment. Capability increments are based on a balance of
capability, delivery timeline, technology maturity, risk, and budget.
[9] The navigation message broadcast by each GPS satellite contains
data that enable GPS receivers to determine whether that satellite
should be used to calculate a user's position. If these data indicate
that the satellite can be used, then the satellite is considered
healthy. During on-orbit checkout and later during routine
maintenance, the navigation message is changed to indicate that the
satellite is unhealthy and should not be used.
[10] GAO, Defense Acquisitions: Challenges in Aligning Space System
Components, [hyperlink, http://www.gao.gov/products/GAO-10-55]
(Washington, D.C.: Oct. 29, 2009).
[11] In [hyperlink, http://www.gao.gov/products/GAO-09-325], we
presented our analysis somewhat differently. We showed the probability
of maintaining a constellation of at least 24 GPS satellites as a
function of time. For this report, we used the same underlying data to
present the predicted size of the constellation--at the 95 percent
confidence level--as a function of time. We believe that this
presentation of the data better depicts the impact of our
constellation availability analysis. In figs. 3 through 6, the
analysis shows the guaranteed size of the GPS constellation (at the 95
percent confidence level) under various assumptions, and makes clear
that even under worst-case assumptions, there is a high probability
that the constellation will remain above about 17 satellites.
[12] 75 Fed. Reg. 14,658 (Mar. 26, 2010).
[13] [hyperlink, http://www.gao.gov/products/GAO-09-325].
[14] The Air Force plans to develop OCX in blocks. Block I, to be
delivered in August 2015, will command and control the IIIA satellites
and enable the second civil signal. Block II, to be delivered in
September 2016, will enable the third civil signal, the Military Code,
and the fourth civil signal.
[15] Antispoofing is a process of encrypting one of the codes
broadcast by the satellites. This prevents an enemy from predicting
the code sequence and using that prediction to generate a code that
could be used to deceive a GPS set. The set would believe the
deception code to be real and could falsely calculate its position.
[16] [hyperlink, http://www.gao.gov/products/GAO-10-55].
[17] [hyperlink, http://www.gao.gov/products/GAO-09-325].
[18] White House, U.S. Space-Based Positioning, Navigation, and Timing
Policy, NSPD-39 (Dec. 8, 2004). NSPD-39 is the national space-based
positioning, navigation, and timing policy.
[19] Department of Defense, Joint Staff, Interagency Requirements Plan
(Revised June 2007). The IRP outlines the 2001 interagency
requirements process. The process was revised and approved in 2007 by
JROC as requested by the National Executive Committee for Space-Based
Positioning, Navigation, and Timing.
[20] Air Force Space Command and Department of Transportation, The
Interagency Forum for Operational Requirements (IFOR) Charter (June
11, 2001). The IFOR charter was approved in 2001 to outline roles,
responsibilities, and relationships. The IFOR charter was approved by
both DOD and DOT.
[21] GAO, Military Space Operations: Common Problems and Their Effects
on Satellite and Related Acquisitions, [hyperlink,
http://www.gao.gov/products/GAO-03-825R] (Washington, D.C.: June 2,
2003).
[22] Agreement on the Promotion, Provision and Use of Galileo and GPS
Satellite-Based Navigation Systems and Related Applications, U.S.-
E.C., June 2004. The European Union replaced and succeeded the
European Community on December 1, 2009. Treaty of Lisbon amending the
Treaty on European Union and the Treaty Establishing the European
Community, December 17, 2007, O.J. (C 306) 1 (2007).
[23] Office of the U.S. Trade Representative, "USTR Report to Congress
on U.S. Equipment Industry Access to the Galileo Program and Markets"
(statement before Congress, July 2009).
[24] GAO, GAO Cost Estimating and Assessment Guide: Best Practices for
Developing and Managing Capital Program Costs, [hyperlink,
http://www.gao.gov/products/GAO-09-3SP] (Washington, D.C.: March 2009).
[25] The Weibull distribution is a common two-parameter continuous
probability distribution; it is used to model the random failures of
GPS satellites.
[26] Monte Carlo simulation refers to a computer-based analysis that
uses probability distributions for key variables, selects random
values from each of the distributions simultaneously, and repeats the
random selection over and over. Rather than presenting a single
outcome--such as the mostly likely or average scenario--Monte Carlo
simulations produce a distribution of outcomes that reflect the
probability distributions of modeled uncertain variables.
[27] Our Monte Carlo simulation also included the reliability
functions for each of the three residual satellites; however, we
excluded these satellites from our primary analysis. We did, however,
run an excursion to demonstrate what the effect of including these
residual satellites would be on the predicted size of the
constellation.
[28] Last year we reported our results differently--as the probability
of maintaining a constellation of at least 24 satellites--instead of
the size of the constellation at the 95 percent confidence level.
However, the underlying data generated by our Monte Carlo simulation
can present the information in either way.
[29] [hyperlink, http://www.gao.gov/products/GAO-09-3SP].
[30] Float is the amount of time an activity can slip before affecting
the critical path, which is the longest duration path through the
sequenced list of activities.
[31] [hyperlink, http://www.gao.gov/products/GAO-09-3SP].
[End of section]
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