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.