The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided bombs, or "dumb bombs" into all-weather "smart" bombs. JDAM-equipped bombs are guided by an inertial guidance system connected to a Global Positioning System (GPS) receiver. This gives them a range of up to . JDAM-equipped bombs range from to . When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature which takes the place of the normal "dumb bomb" nomenclature to which it is attached. JDAM is a joint project of the United States Air Force and the United States Navy.