Piecewise configurable military code direct acquisition method based on parallel frequency and parallel code search

Abstract

The invention relates to a piecewise configurable military code direct acquisition method based on parallel frequency and parallel code search. Satellite signals are firstly down converted to basebandsatellite signals, and through down sampling processing, the sampling rate is similar to the bandwidth of the baseband satellite signals; 2 ms of satellite signals after down sampling and 2 ms of local pseudo code data are then cached; after piecewise stitching processing is carried out on the cached satellite signals and the local pseudo code, FFT operation is carried out, and after complex multiplication, IFFT operation is carried out; and finally, Doppler distribution of a corresponding code phase is acquired for peak detection to acquire a code phase and a Doppler value, the former stepsare repeated for M times to complete acquisition. Thus, even if the time ambiguity of the code phase is large, military code direct acquisition can be completed 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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