Small Scale Anomalies in Omega Position Data Revealed with GPS

Richard Barr, Tim Armstrong, Scott Arrell

Abstract:	The basic GPS system provides at least an order of magnitude increase in navigational accuracy over the Omega system with a resolution down from 0.5 to 0.05 nautical miles. The larger error of the Omega system results from the interaction of the Omega waves with the environment through which they propagate. By knowing one’s position accurately, as one does with GPS, the Omega data can be used to remotely sense the environment. This paper presents results obtained on a Royal New Zealand Airforce flight from New Zealand to the United Kingdom, via Canada, in 1992 when both Omega and GPS data were recorded simultaneously. Periodic errors in Omega position of between 1 and 2 km were observed when passing over the West Coast of Canada. We postulate that these errors result from standing waves produced by the reflection of the Omega Navigation signals by the Coastal and Rocky Mountains. Weaker reflections were also observed well out over the Pacific Ocean between Hawaii and Vancouver Island. Similar Omega/GPS data sets have been recorded on flights from New Zealand to Antarctica. By comparing Omega data from both adjacent and almost identical flight paths the temporal stability of propagation anoma- lies such as those caused by standing waves has been confirmed.
Published in:	Proceedings of the 1994 National Technical Meeting of The Institute of Navigation January 24 - 26, 1994 Catamaran Resort Hotel San Diego, CA
Pages:	943 - 951
Cite this article:	Barr, Richard, Armstrong, Tim, Arrell, Scott, "Small Scale Anomalies in Omega Position Data Revealed with GPS," Proceedings of the 1994 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1994, pp. 943-951.
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