THE GLOBAL POSITIONING SERVICE (GPS) on which satellite navigation devices rely could begin to fail by next year, a report has warned.
The US Government Accountability Office (GAO), said that a lack of investment in satellites means that some are close to failing.
The US Air Force is said to be spending £1.3 billion to bring the US system up to date, but the GAO report says that repairs are not happening fast enough. The GPS network is run by the US military and rented by commercial firms internationally for sat-nav systems.
"It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption," said the report.
"If not, some military operations and some civilian users could be adversely affected," the GAO warned.
The only other such network in place today is the Glonass Russian satellite system, which currently has only 19 operational satellites, with 24 needed to cover the whole globe.
The US system currently has 31 satellites operating, but a number of them are more than four years past their design lifetime.
The GAO predicts a one in five chance that the fleet will drop below 24 at times in 2011 and 2012.
China hopes to have its own GPS system operational by 2011 and the EU's Galileo system, a non-military operation, is expected to have just four satellites on the network by 2011. µ