A Modified Tracking Algorithm for MBOC(6,1,1/11) Signals

Sichao Li, Jinhai Li, and Yuepeng Yan

Abstract:	With the increasing demands of precise positioning, the modern navigation signals of GNSS system will apply the multiplexed binary offset carrier (MBOC) modulation, and MBOC(6,1,1/11) has been selected. Though the new signals own some merits, the receivers will meet many difficulties to track them. Not like the C/A code, the autocorrelation function(ACF) of MBOC(6,1,1/11) has one main peak as well as several side peaks. As a result, the DLL may surfer from false-lock at the side peaks, which would make the receivers not work in the end. To cancel the side peaks, many methods have been advanced, such as autocorrelation side peak cancellation technique (ASPeCT). Here we chiefly consider on a simpler algorithm, which is called ‘BOC-PRN’. It only needs calculate the crosscorrelation function (CCF) of MBOC and PRN, and the result equals the phase error of MBOC signal exactly. However, the loop would lose lock easily because of bit transition and tracking error of carrier. In this paper, we analyze the characteristic of ‘BOC-PRN’ method and develop a modified algorithm, which can be free of bit transition and tracking error of carrier. The new method still computes the CCF of MBOC and PRN. Except that, it also calculates the CCF of early channel and late channel, like the case in general GPS receiver. A well estimation of phase error of MBOC has been gained based on them. The testing results show that in the environment of both weak signal and high dynamic, the novel algorithm could track the MBOC signals steadily and precisely.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2145 - 2149
Cite this article:	Li, Sichao, Li, Jinhai, Yan, Yuepeng, "A Modified Tracking Algorithm for MBOC(6,1,1/11) Signals," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 2145-2149.
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