In marine navigation, Omega refers to a Very Low Frequency (VLF) system used for radio navigation up until September, 1997 when it ceased operation in lieu of the Global Positioning System (GPS). Omega operated in the 10.2 kilohertz (khz) range with a wavelength of 16 nautical miles (nm). Navigation was accomplished by using a receiver which measured the phase-difference contours of pairs of Omega stations. Nautical charts had "Omega lanes" printed on them consisting of two lines of adjacent zero phase-difference contours. An Omega radio receiver would increment and decrement lane counters as a vessel moved through the water. A line of position (LOP) is established by comparing the intersection of at least two Omega lanes. Accuracy of the system was within 1 to 2 nm which was useable for deep sea navigation, but not for coastal piloting.

Original Omega Station Locations

Letter       Name    Latitude   Longitude
Designation

   A         Norway   66 deg N   13 deg E
   B         Trinidad 11 deg N   62 deg W
   C         Hawaii   21 deg N  158 deg W
   D         N Dakota 46 deg N   95 deg W
   H         Japan    35 deg N  129 deg E

Source:

Quartermaster 3 & 2: Rate Training Manual. NAVEDTRA 10149-F. SuDoc Number D207.208/2:Q2/2 (the SuDoc Number is the number you use if you want to get this from a Federal Depository Library)