Integration of GPS and Calibrated LORAN-C for Land Vehicle Navigation in Mountainous Areas

Bryan R. Townsend

Abstract:	The characteristics of GPS and Loran-C in mountainous areas are reviewed in terms of signal availability, accuracy and Loran-C phase distortion. It is shown that, using extensive road data collected in the Canadian Rockies, neither system has the capability of providing continuous navigation due to GPS signal masking and Loran-C signal attenuation. A mathematical model to combine GPS pseudorange and Loran-C Time Difference measurements is therefore proposed. In order to bring the accuracy of Loran-C to a level of accuracy similar to that of single point GPS under Selective Availability prior to the integration of both systems, the effective calibration of permanent Loran-C phase distortions is discussed and demonstrated using LORCAL2 (LORan-C CALibration at The Univsersity of Q&gary), a mobile DGPS system developed by the author. The performance of the integration methodologies proposed herein are demonstrated using GPS and multi-chain Loran-C data collected along a rugged road segment of the Rockies. The analysis of the data shows the advantages of combined GPS/Loran-C for vehicular navigation in areas where line-of-sight to GPS satellites is limited.
Published in:	Proceedings of the 5th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1992) September 16 - 18, 1992 Albuquerque, NM
Pages:	509 - 517
Cite this article:	Townsend, Bryan R., "Integration of GPS and Calibrated LORAN-C for Land Vehicle Navigation in Mountainous Areas," Proceedings of the 5th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1992), Albuquerque, NM, September 1992, pp. 509-517.
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