Implementation of a GNSS Receiver with an Unambiguous Acquisition and Tracking Technique

Q. Chen, Z. Yao, M. Lu

Abstract:	The global navigation satellite system (GNSS) (GPS, Galileo, GLONASS, BeiDou (COMPASS)) would provide more available civil signals and more accurate PVT estimation. On one hand, more satellites in view would enable the user receiver to select the satellites with better geometric distribution to get a better Dilution of Precision (DOP). On the other hand, some GNSS civil signals adopted Binary Offset Carrier (BOC) modulation which could provide the advantages of better code tracking performance, multipath effect reduction, and narrow band interference rejection. However, there are two main problems in the design and implementation of multi-system GNSS receiver. Firstly, some signals adopt BOC modulations and this would arouse the ambiguity problem in signal acquisition and tracking of BOC modulated signal. Secondly, multi-system GNSS receiver would consume more hardware resources than conventional GPS receiver. In this paper we tried to explore solutions to the two problems. To deal with the ambiguity problem, we implemented the GRASS technique in our receiver which could effectively deal with the sine-phased BOC(kn,n) signal’s ambiguity problem. We devised an FFT based acquisition method to effectively calculate the test criterion of the GRASS technique employs. In the tracking progress, we devised a PCF (Pseudo Correlation Function) based detection technique to test false lock and compared its performance with Bump-Jump technique. To reduce the hardware consumption, we devised a universal configurable tracking channel module with which the receiver could track satellite signals of different systems. This channel architecture could reduce the channel numbers used in the multi-system GNSS receiver. We also employed some other methods to reduce hardware resources. We implemented a multi-system GNSS receiver on an Altera development board which could handle GPS L1 C/A, GALILEO E1 OS and BeiDou B1 signals.
Published in:	Proceedings of the 2011 International Technical Meeting of The Institute of Navigation January 24 - 26, 2011 Catamaran Resort Hotel San Diego, CA
Pages:	989 - 996
Cite this article:	Chen, Q., Yao, Z., Lu, M., "Implementation of a GNSS Receiver with an Unambiguous Acquisition and Tracking Technique," Proceedings of the 2011 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2011, pp. 989-996.
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