The Theoretical And Experimental Research On The Widely-Spaced MIMO Detection

Conventional active sonar is faced with more challenges made by the increasing ocean ambient noise and new quiet submarines, especially in shallow water, where strong delay spread, Doppler spread and reverberation occur, it acquires worse performance. Combining with the further researches on MIMO (Multiple Input Multiple Output) radar system and characteristics of underwater acoustics, this article achieves a key research on MIMO sonar.It is that the plane wave model and normal mode model representations are used under the free field and waveguide conditions, after analyzing the characteristics-delay spread and Doppler spread-of underwater acoustic channel. A correlation detector is designed by taking a K-distribution reverberation into consideration, for the reverberation does statistically obey non-Gaussian distribution. To take advantage of non-coherent MIMO processing, an orthogonal waveform balancing waveform diversity and reverberation suppression is designed. Based on space-time collected MIMO processing, I focus on the detection framework of distributed MIMO system, achieving its constraint conditions, numerical simulation and experimental validation. The performance of the MIMO detector can be enhanced by a complex-domain generalization.In this dissertation, I propose a space-time distributed phased MIMO processing system and its qualitative detection performance. Secondly, I design a complex-domain broadband distributed phased MIMO detector. Finally, experiments in water tank and on Moganshan Lake manifest a better performance achieved by phased MIMO detector in comparison with conventional phased detector.