有色混响噪声背景以及水下动目标径向速度造成的回波和样本失配导致匹配滤波器对于线性调频LFM(linear frequency modulation)回波检测性能下降。基于自适应预白化处理的广义似然比GLRT(generalized likelihood ratio test)方法利用混响噪声背景的自回归AR(autoregressive)模型构建白化滤波器来抑制混响噪声,但回波和混响噪声的混叠会造成AR模型偏差。结合匹配滤波的回波定位特性和基于自适应预白化处理GLRT方法的混响噪声背景抑制特性,提出结合这两种方法的联合检测算法。仿真和实验数据测试表明联合检测算法对于水下动目标LFM回波检测性能优于单纯的零速样本匹配滤波和GLRT方法。
The mismatch between echo and replica caused by underwater moving target(UMT)'s radial velocity degrades the detection performance of the matched filter(MF)for the linear frequency modulation(LFM)signal.By using the focusing property of fractional Fourier transform(FRFT)to that signal,a detection algorithm for UMT's LFM echo based on the discrete fractional Fourier transform(DFRFT)is proposed.This algorithm is less affected by the target's radial velocity compared with the other MF detection algorithm utilizing zero radial velocity replica(ZRVR),and the mathematical relation between the output peak positions of these two algorithms exists in the case of existence of target echo.The algorithm can also estimate the target distance by using this relation.The simulation and experiment show that this algorithm'sdetection performance is better than or equivalent to that of the other MF algorithm utilizing ZRVR for the LFM echo of UMT with unknown radial velocity under reverberation noise background.
