Some Environmental Effects on the Differential Global Positioning System

Wai L. Tsang and Barry A. Stein

Abstract:	The Department of Defense’s Global Positioning System (GPS) satellite constellation will achieve 2-dimensional coverage by 1990. It, however, will not provide world-wide 3- dimensional coverage until 1993. Schemes to augment satellite coverage have been proposed to enhance the constellation duying satellite bulldip. One methodology involves operating GPS in a differential mode which uses ground reference stations. The major benefit of a differential GPS (DGPS) operation is its ability to cancel common errors such as ionospheric and tropospheric effects, as well as satellite clock errors at the user’s location. The communication linkage needed for broadcasting DGPS corrections is susceptible to environmental perturbations as a result of the differential operation. Environmental effects due to terrain, trees and buildings, and other antenna subsystems perturb the received signal and are addressed in this paper. Coarse/acquisition (C/A)-code GPS receivers are used for their size, cost, and weight advantages, and to avoid security issues associated with using a precision (P)-code receiver. Results are generated using predictive modelling to aid in evaluating communications connectivity for afloat and ashore DGPS operations.
Published in:	Proceedings of the 46th Annual Meeting of The Institute of Navigation (1990) June 26 - 28, 1990 Atlantic City, NJ
Pages:	115 - 120
Cite this article:	Tsang, Wai L., Stein, Barry A., "Some Environmental Effects on the Differential Global Positioning System," Proceedings of the 46th Annual Meeting of The Institute of Navigation (1990), Atlantic City, NJ, June 1990, pp. 115-120.
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