GPS system on brink of failure

It is uncertain whether the US Air Force, which is responsible for GPS acquisition and is in the process of modernising the system, will be able to acquire new satellites in time to maintain current GPS service without interruption.

In recent years, the Air Force has struggled to successfully build GPS satellites within cost and on schedule. It also encountered significant technical problems that still threaten its delivery schedule, and struggled with a different contractor.

As a result, the current IIF satellite program has overrun its original cost estimate by about $870 million and the launch of its first satellite has been delayed to November 2009 – almost three years late.

Furthermore, while the Air Force is structuring the new GPS IIIA program to prevent mistakes made on the IIF program, its aim to deploy the next generation of GPS satellites three years faster than the IIF satellites is, somewhat optimistic, given the program's late start, past trends in space acquisitions and challenges facing the new contractor.

Should the Air Force not meet its schedule goals for development of GPS IIIA satellites, it is likely that in 2010, as old satellites begin to fail, the overall GPS constellation will drop below the number of satellites required to provide the level of GPS service that the US government commits to.

In addition to risks facing the acquisition of new GPS satellites, the Air Force has not been fully successful in synchronising the acquisition and development of the next generation of GPS satellites with the ground control and user equipment, thereby delaying the ability of military users to fully utilise new GPS satellite capabilities.

Diffuse leadership has been a contributing factor, given that there is no single authority responsible for synchronising all procurements and fielding related to GPS, and funding has been diverted from ground programs to pay for problems in the space segment.

The Dept of Defence, as well as others involved in ensuring GPS can serve communities beyond the military, have taken prudent steps to manage requirements and co-ordinate among the many organisations involved with GPS.

However, GAO identified challenges in the areas of ensuring civilian requirements can be met and ensuring GPS compatibility with other new, potentially competing global space-based positioning, navigation, and timing systems.