Error Budgets for Space-Based Users of GPS

Jay Schwartz, Neil Fox, Nicholas George, Timothy Orndorff, William Webster

Abstract:	This paper discusses selected issues regarding error budgets for space-based users of GPS. Emphasis is on the accuracy of position and time estimates as a function of measurement errors. For space-based applications, the processing gain from Kalman filtering in conjunction with accurate gravity models is of great importance. Results from computer simulations are provided regarding (1) impacts on processing gain due to correlation of noise in successive measurement samples, and (2) the diminished impact of GDOP due to Kalman filtering. The impact of combining accurate intersatellite range measurements with GPS measurements is explored. This subject can be of interest in applications such as spacecraft docking. Bias errors that are of no concern for position estimation have critical, perhaps overriding, impact on time transfer. Uncalibrated receiver delays and time- stamp biases tend to dominate error budgets for relative time transfer. These delays and their placement in an error budget are discussed.
Published in:	Proceedings of the 1995 National Technical Meeting of The Institute of Navigation January 18 - 20, 1995 Disneyland Hotel Anaheim, CA
Pages:	261 - 268
Cite this article:	Schwartz, Jay, Fox, Neil, George, Nicholas, Orndorff, Timothy, Webster, William, "Error Budgets for Space-Based Users of GPS," Proceedings of the 1995 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 1995, pp. 261-268.
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