Reverberation suppression by utilizing wideband speed sensitive characteristic of sinusoidal frequency modulation signal

Reverberation is the main interference in the detection of underwater targets by active sonar,especially for low-speed target,whose echo frequency is close to that of reverberation.According to the velocity difference of scatters in the process of echo and reverberation,the effective separation of target echo and reverberation is realized by using the characteristics of Sinusoidal Frequency Modulation(SFM) signal.The constraint relation of wideband reverberation suppression and velocity resolution ambiguity was derived for SFM signal,the search model of waveform optimization was established.The data was transformed from frequency domain to speed domain through doppler filering,the reverberation can be reduced by setting an appropriate speed threshold.The relationship between reverberation suppression ability,modulation index and bandwidth of SFM signal is analyzed by simulation.The mean anti-reverberation performance of SFM signal is 7.5 dB better than that of Continuous Wave(CW) signal within the preset speed range.The processing results of moving target test data show that this method can suppress the false alarm caused by strong clutter component in reverberation.The detection ability of moving target can be improved by speed difference feature.