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 . JDAM-equipped bombs range from to . When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature, superseding the
Mark 80 or
BLU (Bomb, Live Unit) nomenclature of the bomb to which it is attached.