Research On Virtual Array Method Of Beamforming For Vector Hydrophones

In sound spatial correlation radius, the beamwidth of the array will become narrower with the increasing of the aperture. However, array size should meet with the practical applications, the aperture is limited. In order to further degrade the beamwidth, virtual array beamforming method is adopted more and more frequently. Using the phase information of the received signal in time domain, the array could be expanded virtually. Computer simulations show that, even under low input signal-to-noise-ratio, the accurate estimation of DOA could be given when the virtual array method is applied to the planar array.Compared with the beamforming of traditional hydrophone array, the vector array beamforming has higher performance, such as narrower beamwidth, lower side-lobe level and so on. So the beamforming and the design of vector array are taken more and more attention, and these have become a hot topic in the underwater acoustics research. In the thesis, beam optimization for planar array is presented firstly. Two algorithms are used in the simulations. The results show that one degrades the first sidelobe, and the other gives the same sidelobe level respectively. Besides that, virtual array method is also studied. By increasing the virtual elements, the aperture is expanded. Based on the above analysis, the methods are included into the research of vector array beamforming. The final results illustrate that the vector array has lower sidelobe than the traditional array using the above methods.At last, we could draw a conclusion that the new method proposed in the thesis is feasible. It avoids the ambiguity of spatial DOA estimation, and improves the resolution for any array.