A fast acquisition method of spaceborne Beidou communication system

Abstract

The invention, which belongs to the spaceborne Beidou communication field, discloses a rapid capturing method of a spaceborne Beidou communication system. According to the method, a folded matched filter structure based on time-sharing multiplexing and a frequency offset iterative operation is employed; with the time-sharing multiplexing flow control, large-range frequency offset capturing is realized; and on the basis of the frequency-offset-iterative-operation-structure-based folded matched filter design, the conflict between the capturing speed and hardware resource occupation is eliminated, so that the large-range frequency offset capturing capability in a spaceborne environment is realized. Moreover, the method has advantages of fast capturing speed and low hardware resource occupation and the like; and the hardware cost can be reduced conveniently. Therefore, the method has the high practical value.

Description

technical field [0001] The invention belongs to the field of space-borne Beidou communication, and relates to a fast acquisition method of a space-borne Beidou communication system. Background technique [0002] Due to the fast movement speed of low-orbit satellites, usually reaching tens of Machs, the resulting Doppler frequency deviation is very large, as high as tens of KHz to hundreds of KHz, which is the number of the carrier frequency deviation range of the vehicle system or handheld system. Ten times, and the rate of change is very fast, so it puts forward very high requirements on the ability of the space-borne Beidou communication system to quickly capture signals. Due to the special application environment and the existence of the above-mentioned difficulties, no literature or reports in related fields have been found yet. The focus of everyone's research is mainly on the acquisition methods of the Beidou communication system in conventional fields (vehicle, airbo...

AI Technical Summary

Problems solved by technology

The time-domain matched filter method needs multiple matched filters to be implemented in parallel to complete the capture of multiple frequency bands, which consumes a lot of hardware resources. The same problem still exists in the Chinese patent "CN102901973A Real-time Parallel Fast Capture Method Based on Beidou Satellite Signals", Chinese Patent " CN1635757 A Multi-beam Frequency Offset Extraction Method and Its Device" and the technical scheme described in the Chinese patent "CN104360357A Beidou Satellite Signal Fast Acquisition Method and System Based on Circular Mode", the above-mentioned patents all use FFT algorithm to capture carrier frequency offset , the amount of FFT transformation of the time-domain signal is too large, and the demand for chip hardware resources and clock processing is high, resulting in several times the cost of the chip, which is not conducive to the cost control of the spaceborne communication system, especially in low-cost applications. prominent (e.g. small satellites)

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