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OMEGA HYPERBOLIC NAVIGATION OMEGA was the first truly global radio navigation system for aircraft, operated by the United States in cooperation with six partner nations. Argentina Norway Liberia France Japan Australia HISTORY Developed by the United States Navy for military aviation users Was approved for full implementation in 1968 Initially, the system was to be used for navigating nuclear bombers across the North Pole to Russia Later it was found useful for submarines John Alvin Pierce, the "Father of Omega," first proposed the use of continuous wave modulation of VLF signals for navigation purposes in the 1940's. RADUX - measuring the phase difference of radio signals to compute a location solution After experimenting with various frequencies, he settled on a phase stable, 10 kHz transmission in the 1950's. "OMEGA" - last letter of the Greek alphabet 1950’s Ambiguity errors Inertial Navigation System (INS) Transistor 1963 Omega Implementation Committee (OIC) charged with designing the new navaid and, on the basis of their experiments, took the decisions about how Omega would work - the choice of frequencies, location of transmitters, power levels, etc. Due to the high cost of constructing VLF antennas (Omega antenna towers were more than 1,200 feet in height), the first experimental transmissions were actually existing VLF communications stations that were modified for Omega transmissions 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. 1968 the U.S. Navy authorized full scale implementation of the Omega System 1971 transferred from the U.S.Navy to the U.S. Coast Guard Omega Navigation System Operations Detail (ONSOD) 1983 Omega achieved full eight station implementation in 1983 and was used by several airlines flying long range routes over water as well as by military forces OPERATION 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 radio navigation principles, an accurate fix of the receiver's position could be calculated. OMEGA employed hyperbolic radio navigation techniques and the chain operated in the VLF portion of the spectrum between 10 to 14 kHz. 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. OMEGA STATIONS Trelew, Argentina - tallest construction in South America. On June 23, 1998 it was demolished after the OMEGA service was shut down. Woodside, Victoria, Australia 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 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.
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