一种基于稀疏快速傅里叶变换的卫星信号捕获算法

A satellite signal acquisition algorithm based on sparse fast Fourier transform

卫星信号搜索捕获时间长短是影响GPS软件接收机的重要因素。为了更快速、准确地完成卫星信号的捕获,文中提出了一种基于稀疏快速傅里叶变换的并行捕获算法。该算法采用取模运算、余数不同的采样思想,首先对中频信号和本地码进行一次下采样来获得中频信号和本地码的一个子集,其次对多普勒频移量进行一次下采样来获得多普勒频移量的一个子集;然后在子集中进行卫星信号的并行捕获。研究结果表明,与GPS卫星信号的并行捕获算法相比,该算法有效地减少了运算量,提高了捕获性能。最后通过实验验证了该算法的正确性。

Satellite signal search acquisition time is an important factor which affect the GPS software receiver. In order to capture satellite signals much quickly and accurately, a parallel acquisition algorithm based on sparse fast Fourier transform is proposed. According to the sampling theory through the remainder, Modulo operation is used in the algorithm. Firstly, the IF signal and the local code are down-sampled to obtain a subset of them. Then, the Doppler shift is down- sampled to obtain a subset of it. Finally, satellite signals are captured in parallel in the subset. Experimental results show that the algorithm can effectively reduce the computation and improve the acquisition performance compared with the parallel acquisition algorithm of GPS signal. Finally the correctness of the algorithm is verified by experiment.