According to an AP story posted on Yahoo News Tuesday, as many as 10,000 military GPS receivers were disabled earlier this year after "incompatible" new software was installed. GPS satellite signals were not jammed or scrambled, and civilian GPS services were unaffected. (According to an Air Force spokesman, Iraq tried to jam GPS signals in 2003, but the strength of the signals required to disrupt GPS renders the jammers highly vulnerable to detection.) The problematic software was installed at military ground control centers on Jan. 11, and the ensuing glitch affected between 8,000 and 10,000 of approximately 800,000 military GPS receivers in service. The AP story quoted an alert from James Lewis, a senior fellow at the Center for Strategic and International Studies. He called the outage a warning: "… in the context of where people are every day trying to figure out how to disrupt GPS." It took the Air Force "less than two weeks" to identify the cause of the glitch and install temporary fixes in the affected receivers. The military remains mum on whether or not any of the units were in critical areas such as Afghanistan or Iraq, and whether or not any key operations were compromised by the glitch.