SHORAN

abbreviation of Short-range Navigation, system for determining the position of a ship or airplane by a radar-beacon pulse signal from the craft that triggers responses from two separate stations on land; from the time intervals between sending the pulse and receiving answers from each of the two stations, the distances of the craft from the two ground stations can be determined. From these distances, exact position can be calculated. Shoran can be accurate to within a few yards in 100 miles (a few metres in 160 kilometres) and, though obsolete for navigation, is much used in aeromagnetic, oceanographic, and hydrographic surveying. Hiran, an improved version, has greater accuracy.