GPS technology advances at risk due to bad oversight, GAO says

GAO report says a lack of coordination could threaten needed satellite deployment

For the past 15 years, the U.S. Global Positioning System has provided essential positioning, navigation and timing services not only to the military, but to civil and commercial activities including agriculture, aviation, power distribution and emergency services. But maintenance and future development of GPS is threatened by ambitious schedules that have not been backed up by appropriate oversight and coordination, according to the Government Accountability Office.

The deployment of the current generation of satellites and services, called GPS IIF, is more than three years behind schedule and has more than doubled its original cost estimates, GAO said. The next generation, GPS IIIA, appears to be on schedule but faces risks from a ground system that will not be completed until the launch of the first IIIA satellite, now scheduled for 2015.

“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,” GAO warned in a report on challenges to the system.


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GPS is developed and operated by the Defense Department, with the Air Force being the lead agency for procurement. The system infrastructure and civilian needs are overseen by DOD and the Transportation Department. Last year, GAO recommended that DOD improve its coordination of development and acquisition with a more unified structure, and some progress has been made. But there still is inadequate interagency coordination for a system that has become essential to many government and commercial activities, GAO said.

DOD has said it does not concur with the recommendation for greater coordination, saying an Interagency Forum for Operational Requirements fulfills the needs for coordinating efforts and offering assurances that GPS operations were not threatened.

“The DOD accepts its responsibility with respect to GPS and is committed to maintaining and improving the services it provides,” Deputy Assistant Secretary of Defense Ronald Jost wrote in reply to GAO's recommendations. “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 under way.”

GPS is a satellite system that provides timing signals to ground-based systems, enabling them to compute position and velocity. Minimum requirements for the system are 24 satellites traveling in six orbital planes 12,500 miles above the Earth. The current system became fully operational in 1995 and has a constellation of 31 active satellites, some of which are approaching the end of their operational life. The satellites provide both an encrypted military signal for use by DOD and its allies and an unencrypted civilian signal available anywhere in the world.

It currently is the only operational system, although several countries are developing their own systems.

The new generation of GPS satellites, along with a new ground control system and user equipment, will provide greater accuracy and a stronger signal to thwart jamming.

But although the first of the IIF satellites was launched in May, its performance in orbit has not been determined. “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,” GAO said. This could put GPS at risk because of the uncertainty of its continued performance.

The GPS IIIA program seems to be on track with a back-to-basics approach to design and development, but plans remain ambitious and maintaining a launch schedule could be a challenge.

Another challenge is the fact that the ground control system will not be operational until 2015, a year after the first launch of the new generation of GPS, which will delay evaluation of the initial performance of the new satellite. Delays in launching the new generation could reduce the number of operational satellites to only about 17 rather than the minimum of 24 by 2018, GAO auditors warned.

A further complication in realizing full benefits of the next generation is the need for new user equipment. Although new GPS signals are expected to be available by 2016, warfighters will not be able to take full advantage of them until 2025, when modernized equipment is fully fielded, GAO found. Providing upgraded services to nonmilitary users is complicated by an interagency requirements process that is relatively untested and lacks detailed guidance, the report states.

“There is still a great deal of confusion about how civil agencies should submit and pay for their requirements,” the report states. “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.”

About the Author

William Jackson is freelance writer and the author of the CyberEye blog.

Reader Comments

Mon, Sep 27, 2010 Air Force Space Command

Air Force Space Command, which has responsibility for sustaining and maintaining the Global Positioning System, feels that the GAO report is overly pessimistic and doesn't adequately acknowledge what AFSPC has done to address constellation sustainment. The Air Force has created the largest, most accurate constellation, with the greatest capability, in the history of GPS; with 31 operational satellites currently on orbit. This is well above the 24 minimum satellites needed for a full constellation and to meet constellation performance standards. Since 1995, GPS has never failed to exceed performance standards.

AFSPC is working to mitigate the challenges identified by the GAO through a number of activities, including: applying a “back to basics” approach to acquisition, continuing to identify additional ways to maximize the life of our operational satellites, implementing robust mission assurance processes, and transforming our launch enterprise.

The first GPS IIF satellite completed on-orbit testing and checkout and was set operational on Aug. 26 as planned. The GPS IIF program is ready for full rate production and continues to build confidence in its production line. Through the institution of robust mission assurance processes, AFSPC is confident in the future of the GPS IIF program.

The follow-on program, GPS IIIA, recently completed critical design review, two months ahead of schedule. AFSPC is optimistic that it’s “back to basics” approach, including stable requirements, mature technologies, and more government oversight, will ensure a successful program, providing the GPS IIIA and its ground segment, OCX, within a timeframe that maintains a robust GPS constellation and supports GPS users.

AFSPC takes great pride in providing GPS performance that exceeds our requirements for the system. AFSPC is committed to the modernization of GPS and is on the path to ensure continued positioning, navigation and timing support to the warfighter, the civil user, and the world.

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