LORAN


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loran

(lôr`ăn'), long-range, accurate radio navigational system used by a ship or aircraft to confirm or to determine its geographical position. The term loran is derived from the words long-range navigaton. Loran, operating in the 1,700-kHz range, measures the time-of-arrival difference between two signals transmitted from two geographically separated ground stations. The pulse from the first station, called the master, triggers the second station, called the slave, into transmitting a similar pulse after a set time delay. Knowing the elapsed time difference, the navigator refers to a loran chart and selects his line of position. The chart contains groups of hyperbolic curves of constant time differences between particular station pairs. The position of the receiver (ship or airplane) will be somewhere along the curve that corresponds to the measured time difference. By taking a similar time-difference reading from a second pair of stations whose curves intersect those of the first pair, a definite geographic fix may be obtained.

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.

LORAN (long-range navigation)

LORAN (long-range navigation)click for a larger image
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.

LORAN

(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.
References in periodicals archive ?
Loran said: "I think it was the right time for me to play second division football in England.
They even developed a procedure whereby in bad weather that prevented visual search, they could use a collection of automatic-direction-finding cuts taken from a survivor's radio plotted from precisely recorded LORAN positions to calculate a location within 1,000 meters--accurate enough to enable SAR operations in instrument flight rule (IFR) conditions.
The problem of converting GPS coordinates to Loran TDs has never really been solved with any easy-to-use method or machine, at least not to the accuracy we are used to today with GPS, or were able to obtain with Loran repeatability in the past.
Loran admitted the culpable homicide at his home in East Calder, West Lothian, in April.
Valiants manager Martin Foyle was keen to sign Loran on a longer term basis to help shore up his defence for the League One campaign.
He was a real special person that passed away (Sunday), my Great Uncle Loran," Stewart said.
After the war, the US Coast Guard established a LORAN (Long-Range Aid to Navigation) radio beacon station on the island and remained there until the facility was turned over to the Japanese Coast Guard in 1993.
The next big milestone for them will be to start nesting here," said Loran O'Toole, manager of the re-introduction project.
Then came Loran, which allowed him to more precisely mark the good fishing spots.
But it might have been different had Luton accepted a penalty chance after Steve Howard was impeded by Tyrone Loran.
Here is his crucial game which enabled Loran to forge ahead.
Pictured at the last meeting in Cardiff are (from left) back row Joanne Kubylak, Jo Blair (field captain), Sarah Watkins, Danielle Hinkson, Rachel Biles, Claire Somers, Sarah Rhodes, Kirsty Eaves, Laura Janes, Katie White (track captain), Amy James; middle row Katy Edmonds, Lyndsey Holt, Nicola Ling, Kim Beck, Emma Williams, Stacey Tapping, Alex Heggie, Sarah Facey, Leonie Patterson, Siouxsie Stickland; front row Becky Dowse, Rebecca Loran, Sammy Vickeridge, Kaylee Edwards, Faye Kavanagh, Becky Charlton, Lauren Brown, Chelsea Smith, Hannah Sharman, Naomi Edwards, Christina Lapsa