The Study Of Anti-reverberation Technology

Reverberation is one of basic physical phenomena in under-water acoustic. It has been a long time since begin to research it and the theory of reverberation is going to be maturity little by little. To active sonar, reverberation mostly be treated as disturb.The work of my paper including two parts: one is the anti-reverberation method of Multi-scale of Feature-based Matched Filter. Another is the anti-reverberation method of Fractional Fourier Transform.In reverberation environments, the performance of detection has great relation with the design of transmit waveform. firstly, this paper analyzed the character of transmit signals and their reverberation. Using the extremely feature difference of self-similarity and kurtosis at level scales of wavelet transform and the difference of correlation among the result of level scales of wavelet transform between the PTFM(pulse trains of frequency modulated) signals and its reverberation, we proposed the method of Muti-scale Feature-based Matched Filter. Simulation showed the method suit to detect the low-doppler object in reverberation environments.Broad-band signals have features as more information, smaller correlation in reverberation background and so on which are propitious to signal detection, parameter estimation and object's feature extraction. For broad-band linear frequency modulation (LFM) signal, a new match method in time-frequency plane— Fractional Fourier Transform (FRFT) is proposed . the LFM signal's energy can be collected highly by adjusting the fractional order. The method improved the detection performance in reverberation environments and can get high anti-Doppler performance. It have many meanings to improve detection performance.