Weak signal quick capture method on basis of part correlation

Abstract

The invention provides a weak signal quick capture method on basis of part correlation, which can meet the requirement of long coherent accumulation of a weak signal, and meanwhile, is suitable for the effect of wide-range Doppler change. The method comprises the following steps: generating 8-path data sequences, obtaining a duplication code, and allowing each path of the data sequence to be subjected to exclusive or operation together with the duplication code so as to obtain 8-path data auxiliary duplication codes; and allowing in-phase base band data and orthogonal base band data to be subjected to coherent accumulation operation through the auxiliary duplication codes and the duplication code, allowing the accumulation result of each path of data sequence to be subjected to FFT (Fast Fourier Transform), and then calculating the quadratic sums of the transformation results so as to judge whether the capture succeeds or not according to the maximal quadratic sum. According to the invention, the 8-path data sequences with different phase positions are adopted, a multi-path parallel coherent processing is adopted according to the processing results of the data sequences, and the coherent integration time in the signal capture process is prolonged as far as possible to an extent that the coherent integration can span several modulation data widths so as to improve the signal-to-noise ratio.

Description

technical field [0001] The invention relates to a method for quickly capturing weak signals based on partial correlation, and belongs to the technical field of measurement and control communication. Background technique [0002] In actual spread spectrum communication system engineering, the direct sequence spread spectrum method is currently the most used and the most typical one. Typical examples include: GPS in the United States, GLONASS in Russia, Galileo in Europe and Compass in China. [0003] The fast acquisition technology of the signal is one of the key technologies of the baseband signal processing of the receiver. Since the signal transmitted by the transmitter includes the carrier, the pseudo code and the required data, in order to accurately obtain the required data, the fast acquisition technology eliminates the carrier in the received signal and pseudocode. [0004] The acquisition principle of the signal is: the measurement and control receiver on the satell...

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Problems solved by technology

[0015] The above requirements are mutually restrictive, and the problems caused are: first, when the signal received by the receiving end is a weak signal, the acquisition needs as long as possible coherent integration time, but the high modulation data rate limits the coherent integration time

Second, when the range of Doppler change between the receiving end and the transmitting end is large, due to the change of the pseudo code rate caused by the Doppler effect, the acquisition of the pseudo code phase is affected

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