When the Omega navigation system was developed, it may have been the ultimate form of navigational position fixing. However, it was soon overtaken by the LORAN system in the United States and, in a few years it was completely eclipsed by the Global Positioning System (GPS), which provided navigational information that was a thousand times more accurate. Omega didn't become fully active until 1983, and ceased operations in 1997.
How the Omega Navigation System Worked
Omega had eight stations around the world. The stations transmitted a Very Low Frequency (VLF) signal, consisting of four musical tones. Each station had a unique four-note phrase, transmitted every 10 seconds.
If an Omega receiver picked up signals from three stations, it would compute a vessel's location by phase comparison. This means that the receiver determined what direction each signal from was coming from; the vessel was at the point where the bearing to Station A intersected the bearings to Stations B and C.
Accuracy with Omega
Omega was very accurate for its time. In the late 1960s, when Omega began operation, navigation was generally the result of a comparison of a dead reckoning position (the computed position of the vessel) with the results of "shooting a star" with a preset sextant. Navigators had to compute the difference between the position preset from the dead reckoning position and the position obtained by observation. This method was accurate, with errors of not more than 1 nautical mile, but required about 20 minutes to take three "star shots" and do the math for each.
Omega could have the information within a few seconds--if three stations were received by the Omega unit. The error with Omega ranged from 2,200 yards to 4 nautical miles.
How Omega Grew and Changed
Omega was tested extensively during the 1950s, with improvements being added. The first part of Omega was approved for implementation in 1968.
By the time of full implementation in 1983, LORAN-C had become the standard for navigation in the waters of the United States, and Decca had long been operational in the North Atlantic and the Pacific.
Equipment modifications, bringing the Omega electronics up to 20th-century standards, were completed in 1996, just one year before the system was scrapped.
Similar--and Competing--Systems Around the World
Other navigation systems, such as Decca, flourished in other parts of the world. The Decca Navigation Company, based in London, sued the United States Government for infringing on its design--a system called DELRAC, which operated so much like Omega, that Omega was originally known as DELRAC/Omega. Decca won a judgment for $44 million.
Another system, LORAN-C, used the same principle as Omega, but LORAN-C was in full operation in 1967, but operated in the United States only. Its accuracy was routinely less than 1/4 nautical mile.
SINS, or Ship's Inertial Navigation System, was the brainchild of North American Aviation and used a gyroscopic inertial navigation system to determine a ship's dead reckoning position by sensing direction and speed. If not reset at the beginning of each voyage, an ever-increasing error crept into the system. SINS systems are standard in all large ships.
The Global Positioning System (GPS) uses an artificial constellation of 24 satellites in geosynchrous orbits around earth. Accuracies of less than 2m can be achieved.
The End of the Omega Navigation System
The Omega Navigation System website, operated by the U.S. Naval Observatory, says it all: "As of September 30, 1997, 0300 UT, the OMEGA Navigation System terminated. All eight OMEGA stations, NORWAY (A), LIBERIA (B), HAWAII (C), NORTH DAKOTA (D), LA REUNION (E) ARGENTINA (F) AUSTRALIA (G) AND JAPAN (H)) around the world have permanently ceased to operate... OMEGA, the first world wide radionavigaton system, operated for over twenty-six years. Users must no longer depend on OMEGA broadcasts for navigation of any kind."