(LOng RAnge Navigation) A ground-based navigation system developed by the U.S. government during World War II. Modeled after the British GEE system, LORAN receivers pinpoint their location by triangulation with three LORAN transmitters, approximately 75 of which are located throughout the world. With 29 ground stations covering all of North America, LORAN's long-range signals provide an economical navigation system, although less precise than GPS with its correction systems (see GPS and GPS augmentation system).
LORAN-C
LORAN-C is the surviving LORAN technology. Developed with great haste during World War II, LORAN-A was still used during the Vietnam war for aircraft navigation. LORAN-B was an improved version, which was abandoned in favor of LORAN-C. LORAN-D modified LORAN-C for short-range use, and LORAN-F was an alternate name for a Motorola navigation system for unmanned drones.
eLORAN
After China shot down its own communications satellite in 2007, there was renewed interest in LORAN as backup to the satellite-based GPS system, should it ever be compromised. eLORAN (an Enhanced LORAN) uses more advanced receivers and transmission modes, which improves LORAN accuracy to eight meters. eLORAN receivers accept all signals within range as well as a new set of correction signals.
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