基于离散方波变换的脉冲星微弱信号周期性检测

摘要

In order to meet the requirements of real-time detection of pulsar weak signal periodicity in X-ray Pulsar Navigation System, this paper presents a novel periodicity detection algorithm based on discrete square wave transform (DSWT) and its FP-GA-based hardware realization method. Firstly, the periodicity detection using DSWT is proved feasible by the comparison of DSWT and FFT; meanwhile, the white noise suppression of DSWT algorithm is studied. Secondly, because the transform kernel of DSWT only takes + 1 or - 1, which is more suitable for hardware implementation, this paper presents the algorithm's FPGA real-ization. Lastly, the experiment board is developed using Xilinx Spartan - 3 series FPGA chip XC3S2000. The experiment results show that the signal-to-noise ratio of signal which DSWT algorithm can detect is lower than that can be detected by FFT algorithm;the time delay of DSWT algorithm is 3 clocks, which is three orders less than that of FFT algorithm; the hardware resource that DSWT algorithm needed is no more than that of FFT algorithm.%为满足X射线脉冲星深空导航系统对脉冲星微弱信号周期性检测的要求,提出了一种基于离散方波变换(DSWT)的周期信号检测算法,并给出了其硬件实现方法.首先,通过对比DSWI和FFI变换核的相似性,证明了DSWT算法进行周期性检测的可行性,同时,研究了DSWT对白噪声的抑制作用;其次,DSWT的变换核仅取+1或-1,更适合硬件电路实现,给出了该算法的FPGA实现方法;最后,采用以Xilinx Spartan-3系列FPGA芯片XC3S2000为核心的开发板组成实验仿真系统,分别对实测和仿真脉冲星数据进行实验.结果表明:1.该算法可检测信噪比低于FFT算法;2.在信号输入完毕后3个时钟周期内即可得出计算结果,耗时比FFT算法少三个数量级;3.实现该算法所需的硬件资源少于FFT算法.