An Efficient Acquisition Strategy for Commercial Beidou-3 Dual-frequency Receivers

摘要

The Chinese Beidou-3 global navigation system broadcasts two modern open-service signals, named B1C and B2a, which are suggested to be involved in the Beidou-3 dual-frequency receivers. As acquisition is the largest resource consumption process in the baseband signal processing of a GNSS receiver, the optimization algorithms of it are of interest. To reduce the reliance on high-performance hardware and the cost of the commercial Beidou-3 receivers, this paper proposed an efficient dual-frequency signal acquisition strategy. The proposed method utilizes the relationships of B1C and B2a, enables a direct acquisition of B2a using accurate signal components (i.e. Doppler and code phase) predicted after captured the B1C signal. The experiment results on real signals demonstrate that the proposed method can successfully capture the B2a signal without a series of FFT blocks but only use three short parallel correlations. Compared with the direct acquisition method, the proposed method can reduce the number of multiplications by 99.9% when the sampling frequency is set to 50MHz, while provide the same acquisition sensitivity.