Study On Supergain Property And Signal Processing Of Hydrophone Arrays

Along with the decreasing noise radiation of underwater vessels, it appears a big challenge to the passive sonar. In this dissertation, we study a supergain hydrophone array to improve the detection performance of passive sonar. Comparison of performance is made between the conventional and supergain array. Beamforming in temporal domain and frequency domain is implemented for wideband signal of the array, and corresponding signal processing method is investigated. All the methods are verified by computer simulations and real-data processing. The main content can be outlined as follows:The first chapter is an introduction.In the second chapter, signal model and noise model are introduced. Under this model, we deduce the supergain weights for hydrophone array and compare the array gain for supergain array and conventional one.In chapter three, we study the supergain beamforming algorithm for narrowband signal and wideband signal in temporal domain and frequency domain , and some computer simulations results are given.Chapter four presents the signal processing methods. We detect signal in three way, namely linear spectrogram detection~ wideband energy detection and modulation detection.In chapter five, supergain processing is performed using experimental data collected from the lake experiment. The manifold of the particular hydrophone array and higher spatial gain compared with the conventional one are obtained.In summary, in this dissertation it is proved by theory deducing~ computer simulations and real-data processing that supergain processing can improve the detection performance of passive sonar significantly.