为了更快、更准、更稳定的捕获到北斗卫星信号,文中提出了一种混频前端抽取FFT伪码并行捕获算法。相比传统FFT捕获算法,采用先对采样数据进行抽取,将FFT计算点数下降为原来的1/5;在平方检波前,再将做完IFFT的数据结果进行周期积分累加,通过判决得到相关峰值。该算法有效地减少了FFT的运算量,降低了系统复杂度,更缩短了信号捕获时间。而且相较于只进行抽取的FFT算法,捕获精度有明显提高。仿真实验验证了本算法的优越性。

In the purpose of capturing the Beidou satellite signal faster, more accurately, more stably, a new FFT pseudo-code parallel acquisition algorithm for extracting at mixing front-end is proposed. Compared to the traditional FFT algorithm, firstly, extracting the sampling data which makes the FFT calculation points reduced to 1/5; Secondly, accumulating the results of IFFT according to a certain period of time before the square detection; Lastly, getting the correlation peak by decision. It is showed that using this algorithm can effectively reduce the FFT computation, minimize the system complexity and shorten the signal acquisition time. And what is different form the FFT algorithm only by extracting, the capture accuracy has significantly improved. The superiority of the proposed method is verified in simulations.