Having evolved from Advanced Bomb Family studies by the US Navy and Air Force in the late 1980s, the JSOW is an unpowered glide bomb fitted with folding wings that deploy after release. These wings greatly extend the JSOW's range, allowing it to be launched from beyond the range of many air defenses. Guidance is by a combination of internal inertial navigation system (INS) and satellite-based Global Positioning System (GPS), improving accuracy and increasing resistance to jamming.