GNSS Cost-Benefit Optimisation by Its Integration with TDRSS and using innovative Minimax Estimate Approach

Victor Bobrov

Abstract:	The errors in MEO SV’s position and in the satellite onboard clock time relatively the GNSS system time standard form two of the most important limiting factors in the user reciver’s ability to determined its position. These types of the errors combine in a measure of GNSS system effectiveness called the User Range Error (URE). The goal of minimising this error contributions has been one of the primary consideration in the design of the future GNSS (GALILEO, GPS IIF/III, GLONASS-M, K). The guaranted achievable MEO SV’s OD&TS accuracy of Galileo, GPS systems performed by MiniMax a priory estimation approach, based on linear programming algorithm is analysed in detail. The influence of unmodeled peturbations, caused by errors of the onboard time scale (instability of the onboard frequency standard), and the so called 'unmodeled accelleration", caused by uncertantes of light pressure forces, thrust of onboard switched off busters at cetera are accounted for along with the error of the one-way pseudo- ranging measurements which is in this approach correlated by worst passible manner and limited in magnitude. The OD&TS accuracy of Galileo, GPS IIF space vehicles depending on a mantioned above factors, with and without of ISL measurements is analysed. It is shown that without Crosslink and Autonav modes, or another ISL mode application, the GalileoSat Definition Concept OD&TS worst with respect to GPS IIF/III baseline. The advantage of the MiniMax method of filtering for a priory accuracy GNSS estimation with comparison to the Least Squares Algorithm (LSQ) is shown.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	1595 - 1603
Cite this article:	Bobrov, Victor, "GNSS Cost-Benefit Optimisation by Its Integration with TDRSS and using innovative Minimax Estimate Approach," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 1595-1603.
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