GPS users could be affected by failing satellites

The satellites that provide the global positioning system (GPS) for missile defence and vehicle navigation are falling apart, according to a report by the United States Government Accountability Office.

According to a report on the state of the satellite network, which was built in the 1990s, the US Air Force will not be able to acquire new satellites in time to maintain current GPS service without interruption.

"Some military operations and some civilian users could be adversely affected," the report said.

The GAO warned, "If the Air Force does not meet its schedule goals for development of GPS IIIA satellites, there will be an increased likelihood that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the US government commits to."

Europe is building its own global positioning system to rival the US service. Called Galileo, the European service will be under civilian control. Galileo is expected to have four satellites operational later this year.