The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided bombs, or “dumb bombs”, into all-weather precision-guided 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). JDAM-equipped bombs range from 500 to 2,000 pounds (230 to 910 kg).

The JDAM is not a stand-alone weapon; rather it is a “bolt-on” guidance package that converts unguided gravity bombs into precision-guided munitions (PGMs). The key components of the system are a tail section with aerodynamic control surfaces, a (body) strake kit, and a combined inertial guidance system and GPS guidance control unit.

The JDAM’s guidance system was jointly developed by the United States Air Force and United States Navy, hence the “joint” in JDAM.