Reverberation is a kind of colored and unstable noise, which doubly spreads in time and space and has close relationship with signal. The existence of reverberation greatly reduced the detecting target performance of active sonar. Because of the complex characteristics of reverberation, traditional methods can't improve sonar's detection performance effectively. So researchers of Institute of Acoustics, Chinese Academy of Sciences conducted a series of studies and put forward a new method to solve the problem. 

The researchers create a novel space time adaptive prewhitener for reverberation based on a two-dimensional autoregressive model. The space time adaptive prewhitener jointly processes received date in angle and Doppler to improve the separation of a target from reverberation. It is more effective than the traditional methods which process data in angle and Doppler separately. The experience results show that the detector using the space time adaptive prewhitener is shown to yield a gain of 9~11 dB in detection than previously one dimension autoregressive prewhitener when operating in a reverberation background containing target echoes.