QR-UKF Fusion of Satellite Selection and RAIM for GNSS Performance Enhancement in Multi-Constellation

F.C. Meng, S. Wang, L. Tao, X.Y. Gu, B.C. Zhu

Abstract:	Monitoring the positioning reliability is of great importance for modern Global Navigation Satellite System (GNSS), especially for receivers who are on duty in multi-constellation. Integrity and relevant techniques are gaining popularity among which many researches focus on receiver autonomous integrity monitoring (RAIM) referring to independent integrity without any external assistance. Reliability improvement usually depends on statistical tests for RAIM, i.e., fault detection and exclusion (FDE) in order to detect and exclude erroneous outliers. In addition, Satellite selection plays a crucial role in decreasing computational complexity for receivers with limited processing units and enhancing positioning accuracy by optimal satellite geometric distribution. We propose a new fast satellite selection algorithm for multi-constellation, which is based on both Newton’s identities for Geometric Dilution of Precision (GDOP) fast computation and optimal satellite geometric distribution for less cycle calculation. An effective closed-form formula is used for GDOP approximation, avoiding conventional matrix inversion. The technology of data fusion adopted by the Extended Kalman Filter (EKF) might suffer from the performance degradation and divergence problem due to the linearization process. In order to deal with above concerns, the model of orthogonal triangular (QR) decomposition of augmented unscented Kalman filter (AUKF) is employed for data fusion to avoid the issues linked with modeling error and noise uncertainties. Simulation results show that we can achieve fairly good performance in modern navigation combining above algorithms. In addition, the method combining satellite selection and RAIM has not appeared in existing literatures and provides a new way for modern navigation. Keywords: GNSS, Satellite selection, GDOP, RAIM, FDE, EKF, AUKF.
Published in:	Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015) September 14 - 18, 2015 Tampa Convention Center Tampa, Florida
Pages:	764 - 776
Cite this article:	Meng, F.C., Wang, S., Tao, L., Gu, X.Y., Zhu, B.C., "QR-UKF Fusion of Satellite Selection and RAIM for GNSS Performance Enhancement in Multi-Constellation," Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015), Tampa, Florida, September 2015, pp. 764-776.
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