A Recursive Quasi-optimal Fast Satellite Selection Method for GNSS Receivers

M. Liu, M-A. Fortin, R. Jr., Landry

Abstract:	This paper presents a recursive quasi-optimal satellite selection algorithm for future GNSS receivers to enhance positioning accuracy and robustness with limited resources. For the next decade, new systems, together with existing systems, will provide as much as 40 visible satellites with 160 multi-frequency signals. Any receiver targeting all in-view GNSS signals with fewer channels will need to choose a subset of satellites to be tracked. This is essential for low cost commercial receivers where hardware channels and navigation computer real-time processing capability are limited (hardware/software limitations, complexity of certification, etc.). For example, in order to choose 32 satellites out of 40, traditional algorithms will need more than 50 billion Floating point Operations (FLOPs), which is a huge load for current embedded processors. The algorithm presented in this paper provides quasi-optimal geometry from any combination of signal sources, such as GNSS satellites, space or ground-based augmentation systems, and local constellations. In contrast with the true optimal algorithm, the recursive quasi-optimal algorithm requires a drastically lower computational load. By incorporating various weighting factors, this algorithm can account for User Equivalent Range Error (UERE) when optimizing DOP. Furthermore, when satellites are temporarily blocked, the algorithm provides a list of next-best replacement satellites as a by-product. Receiver Autonomous Integrity Monitoring (RAIM) constraints can also be applied to this algorithm. All these unique features will enhance the robustness and overall accuracy of GNSS receivers. These advantages are unique compared to other quasi-optimal technique of equivalent computational burden.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	2061 - 2071
Cite this article:	Liu, M., Fortin, M-A., Jr., R., Landry,, "A Recursive Quasi-optimal Fast Satellite Selection Method for GNSS Receivers," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 2061-2071.
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