Multipath and NLOS Signals Identification and Satellite Selection Algorithms for Multi-Constellation Receivers

Nesreen I. Ziedan

Abstract: Multi-constellation GNSS will result in an increase in the number of visible satellites. This will be especially beneficial in challenging environments, where GNSS signals could be blocked or suffer from multipath reflections, like in urban areas or under dense foliage. There are, however, several challenges to multi-constellation receivers. The inclusion of multipath or non-line-of-Sight (NLOS) signals measurements in the navigation solution would result in a degraded positioning accuracy. Moreover, the number of received signals could be very large for a receiver to track them. Selecting random satellites could result in a bad satellite geometry, which would increase the geometry dilution of precession (GDOP), and consequently introduce accuracy degradation. This paper presents two algorithms to mitigate the aforementioned challenges. The first algorithm aims at identifying and excluding signals that suffer from multipath or NLOS errors; the algorithm is called Multipath and NLOS Signals Identification (MNSI). The second algorithm aims at selecting satellites with both a good geometry and high precision ranging signals; the algorithm is called WeightBased Satellite Selection (WBSS). The MNSI algorithm utilizes a geometrical approach to identify signals with large errors. The WBSS algorithm calculates a weight function for each satellite, and the algorithm selects satellites with good geometry and highprecision ranging signals. The performances of the proposed algorithms are verified and compared with other techniques from literature. The results proved that the best accuracy is obtained when applying the MNSI algorithm followed by the WBSS algorithm.
Published in: Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016)
September 12 - 16, 2016
Oregon Convention Center
Portland, Oregon
Pages: 521 - 533
Cite this article: Ziedan, Nesreen I., "Multipath and NLOS Signals Identification and Satellite Selection Algorithms for Multi-Constellation Receivers," Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 521-533.
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