Loran is an acronym for long-range navigation, a hyperbolic navigation system first proposed in the 1930s and implemented as the British Gee system in the early days of the Second World War (1939–45) to home bombers onto their targets. It was further developed by the radiation laboratory of the Massachusetts Institute of Technology, and by 1943 a chain of transmitters was in operation under the control of the US Coast Guard. This became known as Loran-A, which was phased out in the USA in 1980. It is anticipated that in due course all Loran-A stations will be replaced by Loran-C ones. The system probably provides the best combination of accuracy and coverage area of any system yet devised for fixing a position by means of earth-based transmitting stations. It is favoured in some quarters as a possible earth-bound back-up for GPS. There are some 30 Loran-C/Chakya chains, operated jointly by the Americans and Russians, each made up of three to five transmitter stations comprising one master and two secondary transmitters. Four Loran-C chains cover much of north-west Europe. As with all hyperbolic navigation systems the position is plotted by means of a lattice chart and transferred to the nautical chart in use. See also consol; decca; omega.
Subjects: Maritime History.