The Joint Direct Attack Munition (JDAM) is a guidance kit that
converts unguided bombs, or "dumb bombs" into all-weather "smart" munitions. JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a global positioning system (GPS) receiver, giving them a published range of up to 15 nautical miles (28 km). The guidance system was developed by the United States Air Force and United States Navy, hence the "joint" in JDAM. The JDAM was meant to improve upon laser-guided bomb and imaging infrared technology, which can be hindered by bad ground and weather conditions. Laser seekers are now being fitted to some JDAMs
The original article can be found at JDAM and the edit history here.