Studies On Reverberation Model And Anti-reverberation Signal Processing For Active Sonar Systems

This dissertation studies and analyses active sonar reverberation model and anti-reverberation signal processing. Based on the rayleigh-distributed reverberation model, the dissertation especially concentrates on the investigation of non-rayleigh-distributed reverberation model. Anti-reverberation approaches are proposed in this dissertation via the simulation and analysis of the non-rayleigh-distributed reverberation statistical model. The first is to design a better active sonar waveform for improving targets resolution. The second is to meliorate signal processing arithmetic. According to these approaches, the following are main contributions in this dissertation.1. At present, many active sonar systems transmit broad bandwidth waveforms to improve range-resolution and use beamforming to increase signal-to-reverberation power ratio and bearing resolution. This may causes the reverberation statistical model no longer be rayleigh-distributed. According to this phenomena, the dissertation analyses and compares rayleigh-distribution and non-rayleigh-distribution, and then validates influence of receiver operating performance by the phenomena of heavier tail.2. Based on the classical statistical detection theory, the dissertation lucubrates signal detection under non-rayleigh-distributed reverberation background. Through the simulation of receiver operating characteristic curves, influence of receiver operating performance under non-rayleigh-distributed reverberation background are validated again.3. Through the simulating and analyzing of non-rayleigh-distributed reverberation statistical model, we can clearly see that in order to enhance the ability of anti-reverberation, research of active sonar waveform is important. So we first discuss several transmitting signal like continuous wave pulse(CWP) and linear frequency-modulated pulse(LFM), and then compute signal ambiguity function to analyze time-resolution and frequency-resolution. Furthermore, the dissertation introduces a new super-low-frequency and large-time geometric comb waveform. It4. At the end of this dissertation, the arithmetic of signal processing is investigated. In this part, time-frequency model of reverberation is simulated based on the...