空时多普勒频移域运动小目标的抗干扰探测方法

有源声呐使用多普勒敏感信号可在多普勒频移域分离杂波、混响等干扰和运动目标,但低信干比时强干扰的时间旁瓣泄露和多普勒旁瓣泄露会淹没弱目标。针对该问题,提出了一种基于自适应最小均方(LMS)算法和宽带模糊函数(WAF)的运动小目标抗干扰探测方法。首先在空间多普勒频移域上利用基于LMS的自适应陷波器抑制干扰,然后在快时间多普勒频移域上利用WAF探测小目标。给出了理论推导和仿真分析,进行了水池试验。结果表明,该方法可有效抑制强干扰并能准确估计小目标的时延及多普勒频移,在水池试验中约有13 dB的干扰抑制能力。此外,该方法能够容忍归一化幅度起伏方差小于0.5的干扰起伏,提高了有源声呐对运动小目标的探测能力。

Small moving target interference suppression detection method in space-time Doppler frequency shift domain

Active sonar can separate clutter,reverberation and moving targets in the Doppler frequency shift domain by using Doppler sensitive signals,but time leakage and Doppler leakage of strong interference will overwhelm weak targets at low signal-to-interference ratio.Therefore,a small moving target interference suppression detection method based on adaptive Least Mean Square(LMS)algorithm and Wideband Ambiguity Function(WAF)is proposed.Firstly,the adaptive notch filter based on LMS is used to suppress interference in the spatial Doppler frequency shift domain,and then WAF is used to detect targets in the fast-time Doppler frequency shift domain.Numerical simulation and pool experiment are carried out.Simulation results demonstrate that the proposed method can effectively suppress strong interference,and accurately estimate the target delay and Doppler frequency shift.It can obtain about 13 dB interference suppression ability in the experiment.Moreover,it can tolerate interference fluctuation with normalized amplitude fluctuation variance less than 0.5,and improves the active detection ability to small moving targets.