关键词: B1 频点, 电文翻转, 捕获算法, FPGA

Abstract:

The high message transmission rate of GEO (geostationary orbit satellites) for BDS may lead to reduced correlation gain and searching precision of frequency shift in acquisition algorithm. In order to solve this problem, combining with the advantage of traditional partial matched filter and FFT acquisition algorithm, a fast acquisition method which can eliminate transition of navigation message and improve the searching accuracy of frequency shift is proposed. Firstly, theoretical demonstration of the algorithm is given; the algorithm validity is then compared with traditional algorithm’s; finally, the engineering practicability of the algorithm is further verified through FPGA platform. Results of algorithm simulation and FPGA platform test show that in the same condition of pseudo code searching precision, the current method can eliminate transition influence of navigation message on the searching accuracy of doppler shift, and fast capture ability of B1 signal is achieved with high precision under the condition of same searching precision of pseudo code.

Key words: B1 frequency points, data transition, acquisition algorithm, FPGA