Simulation and Analysis of Differential GPS

Robert P. Denaro

Abstract:	Differential GPS is a concept that eliminates some of the common, bias errors experienced by conventional GPS. Differential GPS derives its potential from the fact that the measurement errors are highly correlated. By employing a second GPS receiver with comparison to truth, slowly varying, correlated errors can be isolated and eliminated. The objectives of this effort were to develop a differential GPS simulation facility and to accomplish some preliminary user navigation filter trade-offs. The application for the simulation was civil helicopter operations, especially remote area or offshore precise navigation operations which would benefit from a system such as differential GPS due to the lack of other navigation aids. The overall scope of the simulation development· was to provide a sufficiently high fidelity dynamic motion and propagation environment to enable accurate comparisons of differential GPS implementations. The Monte Carlo simulation provided a sufficiently high fidelity dynamic motion and propagation environment to enable accurate comparisons of alternative differential GPS implementations and navigation filter trade offs. The analyst is provided the capability to adjust most aspects of the system including the flight profile, the receiver Kalman filter, and the signal propagation environment to assess differential GPS performance and parameter sensitivities. Preliminary analysis was conducted. to evaluate alternative implementations of the differential navigation algorithm in both the position and measurement domain. Results show that significant performance gains are achieved when compared with conventional GPS but that differences due to implementation techniques are small. System performance is relatively insensitive to the update rates of the error correction information.
Published in:	Proceedings of the 1984 National Technical Meeting of The Institute of Navigation January 17 - 19, 1984 San Diego, CA
Pages:	225 - 234
Cite this article:	Denaro, Robert P., "Simulation and Analysis of Differential GPS," Proceedings of the 1984 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1984, pp. 225-234.
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