关于雷达接收信号循环平稳特性的分析研究

摘要

Among the conventional radar signal analysis methods,the cyclostationarity based ones have been widely considered because of its good signal recognition and noise suppression ability.In the unknown complex battlefield environment,the signals received by radar receivers are always complicated,especially the coherent echo of active radar signal.It probably occurs that signal characteristics reduce in the nonzero cyclic frequencies,which leads to a lower detective radar signals and an unrealized parameter estimation based on the Cyclostationarity.To solve this problem,the commonly signals such as amplitude modulated and phase shift keying signals were used,then the model of radar signals which received by radar receivers was established.Theoretical analysis on the cyclostationary characteristics was carried out when multiple independent signals were received by a passive radar and when multiple coherent signals were received by an active radar.This paper also highlights how the spectral correlation density at typical cyclostationary frequencies is influenced by the particularity of coherence.The results show that,the cyclostationarity of signal components is preserved in the mixed signals received by passive radar,and the cyclostationarity is not necessarily preserved in the mixed signals that compose of coherent echoes.If the received signals have multiple cyclic frequencies,they can be used synthetically to improve the utilization of the cyclostationarity property.%由于雷达接收机接收到的实际信号一般是多个信号的混合,特别是多个空中目标对雷达辐射信号的相干回波,可能出现非零循环频率处的信号特征退化,导致信号可检测性削弱,甚至基于信号循环平稳特性的参数估计无法实现.针对上述问题,以常见信号样式幅度调制信号和二相编码信号,模拟实际雷达接收信号建立模型,分析了无源雷达接收的多个独立信号和有源雷达接收的多路相干信号的循环平稳特性,研究了在典型循环频率处的谱相关函数受信号相干参数的影响情况.结果表明独立信号分量的循环平稳特性在混合信号中得以保留,而相干回波在多个循环频率可供利用时,可改善混合信号循环平稳信息的利用率和信号检测性能.