GPS satellite M code signal demodulation method based on combination of short code dispreading and timing recovery

Abstract

The invention provides a GPS satellite M code signal demodulation method based on combination of short code dispreading and timing recovery. The mutual promotion relation of short code dispreading and timing recovery is utilized, the signal-to-noise ratio threshold of demodulation can be effectively reduced, the antenna aperture is equivalently reduced, and the construction cost is saved. Firstly, the carrier frequency and carrier phase of a GPS satellite navigation signal are obtained through a typical carrier estimation method, carrier recovery and IQ separation are conducted, and extraction of a GPS M code signal is further achieved through band-pass filtering; and short code decoding is performed on the GPS M code signal to obtain coding gain, timing synchronization is performed by adopting blind processing for the first time on the basis, M code streams including innovation of the M code signals is solved after judgment, and the innovation is fed back to a front end to perform timing synchronization operation on the signals again. The timing synchronization precision can be improved.

Description

technical field

[0001] The invention belongs to the technical field of satellite system monitoring and maintenance, in particular to a GPS satellite M code signal demodulation method based on the combination of short code despreading and timing recovery. Background technique

[0002] With the modernization of GPS satellites, the M code of the GPS satellite navigation system has initially completed global networking, and the corresponding M code navigation receivers have also been put into use. Since the M code signal in the GPS signal is mixed with the C / A code and P code, under the condition that the code pattern and encryption method of the M code cannot be obtained, the local M code signal is mainly constructed by blind demodulation of the GPS signal. , to build a GPS M code receiving device. When performing blind demodulation on M-code signals, a large-caliber high-gain antenna is currently used to receive GPS satellite navigation signals to ensure demodulation performa...

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