Space-Based Navigational System Accuracy Performance Model

Andrew Johnson, Tysen Mueller, Erik Christofferson

Abstract:	A performance simulation has been developed to pre- dict the accuracy of a Wide Area Differential GPS (WADGPS) architecture in order to estimate the time and geographic variation of performance. The structure can accommodate WADGPS hardware and software element design trades as well as the impact of integrity monitoring schemes. The simulation employs a covariance approach which estimates the performance of aircraft navigation with the GPS constellation, augmented by a number of geosyn- chronous earth orbiting (GEO) satellites. The GE0 satel- lites not only provide an additional Ll GPS ranging signal, but also broadcast the WADGPS corrections to the user. These corrections are obtained using Ll/L2 receivers at a collection of geographically dispersed WADGPS reference stations (WRS). A key feature is a geographic color-situation display, which shows the areas where the performance requirements are satisfied. In addition, the situation display can be ad- vanced forward in time for up to 24 hours to see potential holes in the service volume. The impact of losses of any of the GPS or GE0 satellites, as well as losses of any of the WADGPS ground network elements hardware, can be simu- lated by removing these components discretely from the WADGPS architecture in the simulation. Results from a number of nominal and failure-mode conditions are pre- sented in this format.
Published in:	Proceedings of the 1995 National Technical Meeting of The Institute of Navigation January 18 - 20, 1995 Disneyland Hotel Anaheim, CA
Pages:	567 - 576
Cite this article:	Johnson, Andrew, Mueller, Tysen, Christofferson, Erik, "Space-Based Navigational System Accuracy Performance Model," Proceedings of the 1995 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 1995, pp. 567-576.
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