SHORAN

Although SHORAN was used by the military only briefly, surplus equipment soon found a new use in the oil and gas industry, where it was used to position ships with high accuracy for seismic measurements.

In 1938 RCA engineer Stuart William Seeley, while attempting to remove "ghost" signals from an experimental television system, realized that he could measure distances by time differences in radio reception.

[clarification needed] The equipment on board the aircraft includes a transmitter, a receiver, an operator's console and a K-1A model bombing computer.

Changes were made and by June 1951 ground stations were located in more useful areas, such as islands and mountaintops, and training of operators and technicians familiarized them with the system.

During the Retriangulation of Great Britain between 1935 and 1962, the Ordnance Survey primary triangulation of the British Isles was connected to both Norway and Iceland using HIRAN, an enhanced version of SHORAN.

[5] From July to September 1953, the US Air Force used HIRAN to survey a link between three geodetic stations in Norway and three on the Scottish mainland and Shetland islands.

The final results and assessment were computed from observation of ground survey positions, including stations in both Iceland and the Faroe Islands.

[3] The operation was largely successful, but the Ordnance Survey considered that the results were not of a geodetic standard necessary for primary triangulation, and a 12 metres (39 ft) discrepancy existed in the measurements between Norwegian stations.

[5] Beginning in the late 1940s and continuing into the 1980s surplus SHORAN systems had become widely used to provide precision navigation in oil and gas exploration industry.

SHORAN chains consisting of three or four shore stations were used to provide highly accurate navigation across large exploration tracts and as much as 200 miles (320 km) offshore.

Frequently, the massive vacuum tube transmitters were fitted with solid-state control boxes for more reliable operation and to improve reception of weaker signals over the horizon.