General BOC signal fuzzy-free tracking technology implementation method adopting software phase lock loops (SPLLs)

Abstract

The invention belongs to a general BOC signal fuzzy-free tracking technology implementation method adopting software phase lock loops (SPLLs). According to the implementation method, a related branchis additionally arranged on the basis of a traditional tracking loop, and thus through a three-loop structure of the carrier loop, the subcarrier loop and the code loop, fuzzy-free tracking of BOC signals is dynamically achieved. The implementation method is implemented on an FPGA+DSP platform, an FPGA achieves carrier NCO, subcarrier NCO and pseudo-code NCO and completes related operation and integral removal of seven related branches, a DSP completes phase demodulation filtering of the carrier loop, the subcarrier loop and the code loop, and the implementation method is general for the BOC signals of all modulation coefficients, and has the equivalent tracking sensitivity and higher tracking accuracy compared with the traditional tracking loop.

Description

technical field [0001] The invention belongs to a signal processing method of a satellite navigation receiver, and in particular relates to a method for realizing a general BOC signal non-fuzzy tracking technology using SPLL. Background technique [0002] The BOC modulation method is the satellite navigation modulation method that both Beidou and GPS will adopt in the future. Its characteristic is to add a subcarrier modulation link between the pseudo code modulation and carrier modulation of BPSK modulation, and move the spectrum of the satellite signal to the left and right sides of the center frequency point. , which can not only ensure that the carrier center frequency is shared with the early signal, avoid spectrum interference between systems, but also bring a larger Gabor bandwidth and improve the potential code tracking accuracy of the navigation signal. However, the autocorrelation function of the BOC signal has a multi-peak characteristic. Once the auxiliary peak i...

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Problems solved by technology

[0002] The BOC modulation method is the satellite navigation modulation method that both Beidou and GPS will adopt in the future. Its characteristic is to add a subcarrier modulation link between the pseudo code modulation and carrier modulation of BPSK modulation, and move the spectrum of the satellite signal to the left and right sides of the center frequency point. , which can not only ensure that the carrier center frequency is shared with the early signal, avoid spectrum interference between systems, but also bring a larger Gabor bandwidth and improve the potential code tracking accuracy of the navigation signal. However, the autocorrelation function of the BOC signal has a multi-peak characteristic. Once the auxiliary peak is locked by mistake, it will cause a large code tracking error

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