Ces petits bijoux, pilotés par GPS ("satellite guided") ont une précision (erreur circulaire probable) de 13 mètres (30 mètres en mode dégradé quand le signal GPS n’est pas disponible).
Joint Direct Attack Munition (JDAM) GBU-31 - Smart Weapons
▻http://fas.org/man/dod-101/sys/smart/jdam.htm
Once released, the bomb’s INS/GPS will take over and guide the bomb to its target regardless of weather. Guidance is accomplished via the tight coupling of an accurate Global Positioning System (GPS) with a 3-axis Inertial Navigation System (INS). The Guidance Control Unit (GCU) provides accurate guidance in both GPS-aided INS modes of operation (13 meter (m) Circular Error Probable (CEP)) and INS-only modes of operation (30 m CEP). INS only is defined as GPS quality hand-off from the aircraft with GPS unavailable to the weapon (e.g. GPS jammed). In the event JDAM is unable to receive GPS signals after launch for any reason, jamming or otherwise, the INS will provide rate and acceleration measurements which the weapon software will develop into a navigation solution. The Guidance Control Unit provides accurate guidance in both GPS-aided INS modes of operation and INS-only modes of operation. This inherent JDAM capability will counter the threat from near-term technological advances in GPS jamming.