DENVER — A problem that rendered as many as 10,000 U.S. military GPS receivers useless for days is a warning to safeguard a system that enemies would love to disrupt, a defense expert says.
The Air Force has not said how many weapons, planes or other systems were affected or whether any were in use in Iraq or Afghanistan. But the problem, blamed on incompatible software, highlights the military's reliance on the Global Positioning System and the need to protect technology that has become essential for protecting troops, tracking vehicles and targeting weapons.
"Everything that moves uses it," said John Pike, director of Globalsecurity.org, which tracks military and homeland security news. "It is so central to the American style of war that you just couldn't leave home without it."
The problem occurred when new software was installed in ground control systems for GPS satellites on Jan. 11, the Air Force said.
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Officials said between 8,000 and 10,000 receivers could have been affected, out of more than 800,000 in use across the military.
In a series of e-mails to the Associated Press, the Air Force initially blamed a contractor for defective software in the affected receivers but later said it was a compatibility issue rather than a defect. The Air Force didn't immediately respond to a request for clarification.
The Air Force said it hadn't tested the affected receivers before installing the new software in the ground control system.
At least 100 U.S. defense systems rely on GPS, including aircraft, ships, armored vehicles, bombs and artillery shells.
Because GPS makes weapons more accurate, the military needs fewer warheads and fewer personnel to take out targets. But a leaner, GPS-dependent military becomes dangerously vulnerable if the technology is knocked out.
James Lewis, a senior fellow at the Center for Strategic and International Studies, said the glitch was a warning "in the context where people are every day trying to figure out how to disrupt GPS."
The Air Force said it took less than two weeks for the military to identify the cause and begin devising and installing a temporary fix. It did not say how long it took to install the temporary fix everywhere it was needed but said a permanent fix is being distributed.