Complexity Reduction for High Sensitivity Acquisition of GNSS Signals with a Secondary Code

Jérôme Leclère, René Jr Landry

Abstract:	Modern GNSS signals include several innovations compared to the GPS L1 C/A signal. Among them, there is the secondary code and the pilot channel that is free of data. The use of a secondary code brings several advantages, but it also complicates the acquisition process. Indeed, it implies a potential sign transition between each consecutive primary code period, which is problematic when dealing with circular correlation. This paper focuses on high sensitivity acquisition with fast Fourier transform (FFT) based parallel code search, to propose three different methods to reduce the complexity of the correlation with the secondary code, without impacting the detection performance. The idea behind the methods is to make zeros appears in the secondary code. The proposed methods are applied to the GPS L5, and Galileo E1 OS and E5 signals, and it is shown that the number of operations and the processing time for both software and hardware receiver can always be halved for any code with the first method. The two other methods provide even better performance, with a reduction up to 76 %, although not applicable to every code.
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:	436 - 443
Cite this article:	Leclère, Jérôme, Landry, René Jr, "Complexity Reduction for High Sensitivity Acquisition of GNSS Signals with a Secondary Code," Proceedings of the 29th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 436-443. https://doi.org/10.33012/2016.14753
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