LORAN

loran

[′lȯr‚an]

(navigation)

The designation of a family of radio navigation systems by which hyperbolic lines of position are determined by measuring the difference in the times of reception of synchronized pulse signals from two or more fixed transmitters. Derived from long-range navigation.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

LORAN (long-range navigation)

A radio navigation system operating in an LF (low frequency) band. It utilizes master and slave stations transmitting timed pulses. The time difference between receptions of pulses from several stations establishes a hyperbolic position line, which may be identified from a LORAN chart. A fix can be obtained by drawing two hyperbolic position lines. LORAN A operates in the 1750 to 1950 kHz frequency band, while LORAN C operates in the 90 to 110 kHz frequency band.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

LORAN

(1) (LOng RAnge) A wide area nework technology. See LoRa.

(2) (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 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 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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