Fast acquisition algorithm based on improved coherent average method for high dynamic BDS signal

To solve the question of satellite signal volatile lock under high dynamic condition, an improved fast acquisition algorithm is proposed for high dynamic BDS satellite signal. This algorithm combines the advantages of FFT technology, coherent average method and average correlation method, and simplifies traditional two-dimensional detecting process into two one-dimension detecting process. Firstly, the traditional coherent averaging method is improved to enhance the signal-to-noise ratio of the signal by directly compensating the frequency of the intermediate frequency signal. Then, the carrier Doppler frequency shift is determined by the FFT algorithm and the pseudo-code phase is determined by the average correlation algorithm. Finally, complete two experiments, intermediate frequency measured date processing experiment and high dynamic simulation data processing experiment. Experimental results show that this method reduces acquiring time and improves acquiring precision, and its calculation is just several tenths of traditional FFT algorithm. The proposed algorithm has an excellent high dynamical adaptability. At the high dynamic condition with a speed 3500m/s, an accelerated speed of 25g, it is able to acquire BDS signal quickly. Besides, the proposed algorithm has a good applicability under the order low SNR conditions.