非合作直扩信号分析的算法与实现

The algorithm and implementation of non-cooperative direct sequence spread spectrum signal analysis

针对直扩信号频谱展宽、功率谱密度下降造成的信号侦测难度,本文分析了非合作直扩信号的信号特征,采用了一种基于FPGA+POWERPC硬件架构的非合作直扩信号参数估计与信号解调的实现方法。通过对直扩信号的载频估计、扩频码速率估计、扩频码周期估计、信息码速率估计等信号参数侦测算法,以及直扩信号的PN码捕获与跟踪、BPSK/QPSK信号解调、BCH/Viterbi译码等算法的实现,获得了相关测试结果,扩频码载频误差≤25Hz(SNR>10dB),扩频码速率误差≤275Hz,扩频码周期测量误差<0.2s。

Aiming at the difficulty of signal detection caused by widening spectrum and decreasing power spectral density of DSSS signal,the signal characteristics of non-cooperative DSSS signal are analyzed in this paper.A method of parameter estimation and signal demodulation of non-cooperative DSSS signal based on FPGA + POWER PC hardware architecture is adopted.Through the realization of carrier frequency estimation,spread spectrum code rate estimation,spread spectrum code period estimation, information code rate estimation and other signal parameter detection algorithms,as well as PN code acquisition and tracking,BPSK/QPSK signal demodulation,BCH/Viterbi decoding and other algorithms of direct spread spectrum signal,the related test results are obtained.The carrier frequency error of spread spectrum code ≤25 Hz(SNR>10 dB),spread spectrum code rate error ≤275 Hz,spread spectrum code period measurement error < 0.2 s.