不确实波导环境下基于子空间建模的恒虚警检测方法

摘要

The troubles of active sonar faced in the uncertain shallow water waveguide mainly are echo uncertainty and reverberation interference.So a detecting and estimating method by a constant false alarm rate(CFAR)detector for subspace echo was presented.The CFAR detector was structured by the generalized likelihood ratio test(GLRT)theory under the conditions that the echo was modeled as a subspace signal,the reverberation interference was modeled as a like signal one,and the maximum likelihood estimation of the reverberation correlation matrix was substituted into likelihood ratio test. The processed results to the simulated data and the real ones show that the CFAR detector has better coherent matching ability to the uncertain channel,better tolerance to the channel uncertainty,by which the better pulse compression effect can be obtained,the target position estimation precision can be improved,and the detection performance can be improved by 1-2.5 dB compared with the conventional matching filter.%浅海主动声纳检测与估计面临的主要问题是不确实浅海信道导致的回波信号不确实和混响干扰.为此,本文提出一种子空间回波信号的恒虚警(CFAR)检测与估计方法:对不确实浅海波导中的回波信号采用子空间信号建模方法;将混响干扰建模为一种类信号干扰,基于广义似然比检验(GLRT)的思想,将混响相关矩阵的最大似然估计代入到似然比检测中,由于GLRT具有恒虚警特性,最终得到子空间回波信号的恒虚警检测器.通过仿真和实际数据处理分析表明,这种子空间回波信号恒虚警检测器对不确实信道具有很好的相干匹配能力,对信道不确实性具有较好的宽容性,能得到较好的脉冲压缩效果,提高目标位置估计精度.较之常规匹配滤波器,其检测性能可提高1～2.5 dB.