Segmented configurable military code direct capture method based on parallel frequency and parallel code search

Abstract

The invention relates to a segmented configurable military code direct capture method based on parallel frequency and parallel code search. First, the satellite signal is down-converted into a baseband satellite signal, and the sampling rate is similar to the bandwidth of the baseband satellite signal through down-sampling processing; and then Cache the 2ms downsampled satellite signal and 2ms local pseudocode data; then perform FFT operation on the cached satellite signal and local pseudocode after segmentation splicing processing, and perform IFFT operation after multiple multiplication; finally, obtain the corresponding code After the Doppler distribution of the phase, the peak detection is performed to obtain the code phase and Doppler value, and the previous steps are repeated M times to complete the capture. Therefore, even when the code phase time ambiguity is large, the military code can be directly captured quickly.

Description

technical field [0001] The invention relates to a segmented configurable military code direct capture method based on parallel frequency and parallel code search, belonging to the technical field of satellite navigation applications. Background technique [0002] With the steady advancement of my country's Beidou satellite navigation system and the rapid development of the navigation industry, Beidou navigation receivers are playing an increasingly important role in the military and civilian fields. In the Beidou satellite navigation system, two ranging codes are often used: civilian code (C code) and military code (P code). Among them, the civilian code can generally meet the positioning needs of ordinary civilian users; the military code adopts advanced encryption technology and is designed for military use. The civilian code cycle is short. When the civilian code is used for positioning, the civilian code capture time is short, and the satellite positioning can be quickl...

AI Technical Summary

Problems solved by technology

However, when the uncertainty of the code phase time is too large (such as ±1s) or the carrier Doppler frequency offset is too large, this method has problems such as long acquisition time (tens of seconds) and large hardware resource consumption.

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