Pentagon raises concerns over homemade GPS jammers​​​​

　　Government officials and communications experts are evaluating the public safety and security implications of a newly released online article that provides guidance on building inexpensive devices that can interfere with global positioning system (GPS) signals.

　　Authorities say information in an article in the current issue of Phrack, an online hacking magazine, could put GPS equipment used for commercial navigation and military operations at risk.

　　The Phrack article provides a detailed guide to building a low-cost, portable GPS jammer using components readily available from electronics suppliers. According to the article, "The onslaught of cheap GPS-based navigation has made it necessary for ordinary citizens to master the art of electronic warfare.

　　The U.S. Department of Defense, which faces the possibility of its GPS-guided weapons clashing with Russian-made GPS jammers in Iraq, has anti-jamming technology.

　　A Pentagon spokesman said the impact of the homemade jammers described in the article was "somewhat severe" because the use of such jammers "could disrupt commercial operations."

　　The Federal Aviation Administration is developing a nationwide GPS-based precision landing system. The Coast Guard operates GPS-based marine navigation systems on both coasts, the Great Lakes, the Inland Waterway and Hawaii. Bill Moseley, a spokesman for the Department of Transportation, the parent agency of the FAA and the Coast Guard, said his department is well aware of the threat posed by GPS jammers.