The Omega Navigation System, used for long range navigation by military ships and aircraft, was the first truly global-range radio navigation system. Operated by the United States in cooperation with six partner nations (Argentina, Norway, Liberia, France, Japan, and Australia), it enabled ships and aircraft to determine their position by receiving very low frequency (VLF) radio signals in the range 10 to 14 kHz, transmitted by a network of fixed terrestrial radio beacons. Omega was approved for development in 1968, and by 1971 six of the eight stations in the chain had become operational, with the final stations becoming operational several years later. Coast Guard personnel operated the two U.S. stations: one in LaMoure, North Dakota and the other in Kaneohe, Hawaii on the island of Oahu. However, with 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 shut down permanently in September of 1997.