Omega (navigation system)
OMEGA was the first truly global radio navigation system for aircraft, operated by the United States in cooperation with six partner nations.
History
OMEGA was originally developed by the United States Navy for military aviation users. It was approved for development in 1968 and promised a true worldwide oceanic coverage capability with only eight transmitters and the ability to achieve a four mile accuracy when fixing a position. Initially, the system was to be used for navigating nuclear bombers across the North Pole to Russia. Later, it was found useful for submarines.[1]
Each Omega station transmitted a very low frequency signal which consisted of a pattern of four tones unique to the station that was repeated every ten seconds. Because of this and radionavigation principles, an accurate fix of the receiver's position could be calculated. OMEGA employed hyperbolic radionavigation techniques and the chain operated in the VLF portion of the spectrum between 10 to 14 kHz. Near its end, it evolved into a system used primarily by the civil community. By receiving signals from three stations, an Omega receiver could locate a position to within 4 nautical miles using the principle of phase comparison of signals.[2]
Omega stations used very extensive antennas in order to transmit their extremely low frequencies. Specifically, they used grounded or insulated guyed masts with umbrella antennas, or wire-spans across fjords. Some Omega antennas were the tallest constructions on the continent where they stood or still stand.
When six of the eight station chain became operational in 1971, day to day operations were managed by the United States Coast Guard in partnership with Argentina, Norway, Liberia, and France. The Japanese and Australian stations became operational several years later. Coast Guard personnel operated two US stations: one in LaMoure, North Dakota and the other in Kaneohe, Hawaii on the island of Oahu.
Due to the success of the Global Positioning System the use of Omega declined during the 1990s, to a point where the cost of operating Omega could no longer be justified. Omega was permanently terminated on September 30, 1997 and all stations ceased operation.
Some of the stations, such as the LaMoure station, are now used for submarine communications.
OMEGA stations
There were nine Omega stations in total:
- Bratland, Norway (station A - 66°25′13″N 13°08′13″E / 66.420189°N 13.136964°E), fjord-span antenna. the only European Omega transmitter. It used a very unusual antenna, which consisted of several wires spun between two concrete anchor blocks 3500 metres apart. One of these blocks was situated on the mainland of Norway and the other on Aldra island. The antenna was dismantled in 2002.
- Trinidad (station B until 1976, replaced by station in Paynesville, Liberia) 10°41′58″N 61°38′19″W / 10.69938°N 61.638708°W)
- Paynesville, Liberia (station B - 6°18′20″N 10°39′44″W / 6.305509°N 10.662206°W): It was inaugurated in 1976 and used as radio antenna an umbrella aerial mounted on a 417 metre tall grounded guyed mast of lattice steel, which was the tallest structure ever built in Africa. The station was turned over to the government of Liberia after the termination of the Omega Navigation System on September 30, 1997. As of February 2006, the Omega Tower near Paynesville is still standing, although it is unused. Access to the tower is not restricted, and it is possible to climb it.
- Kaneohe, Hawaii, USA (station C - 21°24′17″N 157°49′51″W / 21.404700°N 157.830822°W): One of two stations operated by the USCG. Inaugurated in 1943, it used an antenna span over Haiku Valley. At the end of the sixties it was transformed into a transmitter for the OMEGA Navigation System
- La Moure, North Dakota, USA (station D - 46°21′57″N 98°20′08″W / 46.365944°N 98.335617°W): The other station operated by the USCG. It used a 365.25 metre tall guyed mast as an antenna, which is insulated against ground. Since the shutdown of the Omega Navigation System, it is used for VLF transmissions to submarines.
- Chabrier, Réunion (station E - 20°58′27″S 55°17′24″E / 20.974139°S 55.289894°E): used a 428 metre tall grounded guyed mast, which carried an umbrella antenna. Demolished on April 14, 1999
- Trelew, Argentina (station F - 43°03′13″S 65°11′27″W / 43.053553°S 65.190781°W): a 366 metre high guyed steel mast, insulated against ground, which was situated at Golfo Nuevo, 40 km outside Trelew. It was the tallest construction in South America. On June 23 1998 it was demolished after the OMEGA service was shut down.
- Woodside, Victoria, Australia (station G, now known as VLF transmitter Woodside - 38°28′52″S 146°56′07″E / 38.481228°S 146.935294°E): The station in Australia was originally intended for New Zealand but was moved to Australia after protests from anti-war protestors. An umbrella aerial is used, which is carried by a 432 metre high grounded steel framework guyed mast. This mast is the highest construction in the southern hemisphere. Since the shutdown of OMEGA it is used as a transmitter for orders to submarines at 13 kHz.
- Shushi-Wan, Japan (station H - 34°36′53″N 129°27′13″E / 34.614739°N 129.453644°E): located on Tsushima Island: a 389 metre tall mast insulated against ground.
See also
- Alpha, the Russian counterpart of the Omega Navigation System, still in use as of 2006.
- LORAN, low frequency terrestrial radio navigation system, still in use.
- CHAYKA, the Russian counterpart of LORAN
- SHORAN
- Oboe (navigation)
- G-H (navigation)
- GEE (navigation)
Bibliography
- Scott, R. E. 1969. Study and Evaluation of the Omega Navigation System for transoceanic navigation by civil aviation. FAARD-69-39.
- Asche, George P. USCG 1972. Omega system of global navigation. International Hydrographic Review 50 (1):87-99.
- Turner, Nicholas. 1973. Omega: a documented analysis. Australian Journal of International Affairs:291-305.
- Pierce, J.A. 1974. Omega: Facts, Hopes and Dreams. Cambridge Mass: Harvard Univ Div of Engineering and Applied Physics.
- Wilkes, Owen, Nils Petter Gleditsch, and Ingvar Botnen. 1987. Loran-C and Omega : a study of the military importance of radio navigation aids. Oslo; Oxford ; New York: Norwegian University Press/Oxford University Press. ISBN 8200077039
- Gibbs, Graham. 1997. Teaming a product and a global market: a Canadian Marconi company success story. Reston, VA: American Institute of Aeronautics and Astronautics. ISBN 1563472252; ISBN 978-1563472251 [A case study of the commercial development of the Omega Navigation System]