Sunday, January 22, 2012

Omega Navigation System

The Antipodean Mariner was riding through Gippsland this weekend and passed the defunct Omega navigation station still towering over the Victorian rural landscape. Omega was a Cold War inspired long range navigation system which expanded the principles of Decca and Loran. It used synchronised, ultra-low frequency radio to create a globally intersecting grid of Lines of Position (LOP's) which could penetrate underwater. US nuclear submarines streamed an antenna and could refix their inertial navigation systems without surfacing and potentially revealing their position to an orbiting satellite.


Omega tower at Woodside, Victoria: photo credit Far_Tracer


New Zealand was the preferred site to give the best global LOP intersection, but Kiwi's were staunchly against nuclear proliferation and scuttled the station in Aotearoa.

Merchant ships were permitted to use Omega, but the system was only marginally better than a sunsight, with an accuracy of about four miles. Corrections had to be applied to compensate for the height of the ionosphere for the time of day, signal strength was patchy in the Southern Hemisphere and the LOP's distorted close (200 Nm) to any of the seven base stations. Later Omega receivers integrated the LOP's and corrections to give latitude and longitude.


Omega hardware at Port Albert Maritime Museum

Omega begat the Transit satellite navigation, which in turn begat GPS which is on your smart phone. The Omega navigation system was turned off in 1997, technically redundant after 26 years in operation. In Victoria, the Port Albert Maritime Museum inherited the hardware and have an audio-visual display of the system's operation.

The Antiodean Mariner

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