(GPS) a commonly hand-held, satellite-based navigational device that records x,y,z coordinates and other data allowing users to determine their location on the surface of the earth (usually within meters) —note GPS signals are obtained from satellites orbiting the earth such as NAVSTAR (NAVigation System with Time And Ranging), a network of 24 radiotransmitting satellites and ground stations developed by the US Department of Defense This definition last updated 10/27/2008