In a ten day exercise along the coasts of North Carolina and Florida, the U.S. Navy tested GPS jamming, and counter-jamming, equipment. The tests ended on June 20th. Mariners were warned that their GPS equipment might be unreliable, or not work at all, up to a hundred kilometers from the coast. The technology being tested may be the Lockheed-Martin G-STAR Spatial Temporal Anti-Jam Receiver. Developed in the late 1990s, G-STAR uses several technologies to defeat GPS jammers. The G-STAR is also a key part of the new Joint Air-to- Surface Stand-off Missile (JASSM). With a range of up to 400 kilometers, JASSM is highly dependent on GPS to find its target.