Research On Signal Processing Based On Single Vector Hydrophone

Vector acoustic field is a very important part of sound wave, but the vector information of acoustic wave has been unwitnessed for a long time. Vector hydrophone, also called combined sensor, is combined by traditional and omni-directional pressure hydrophone and natural dipole independent on frequency, which can co-locating and simultaneously measures pressure(scalar field) and particle velocity(vector field) of acoustic field. Combined processing based on pressure and particle velocity can get better detection effect and better estimation precision than processing only on pressure. So the technology associated with vector hydrophone becomes a very important investigative aspect in underwater acoustic field. Signal processing based on vector hydrophone is the main content of the thesis, which has academic and engineering significance.Firstly, the thesis sets forth the physical fundamentals of the combined signal processing with acoustic pressure and particle velocity. For the signal radiation from one coherent source, its waves of acoustic pressure and particle velocity are fully correlated, while in isotropic acoustic field, they are uncorrelated. For a single vector hydrophone, the particle velocity sensor bears dipole directivity, so acoustic pressure and particle velocity combined processing can form the single side directivity of arbitrary bearing, which is functionary to suppressing the coherent interference.Secondly, 4 methods of azimuth estimation based on vector hydrophone according to forms of nosie and signal are brought forward. The principles of these 4methods are set forth, simulating them by computer. Acoustic intensity averager can effectively suppress isotropic non-coherent interference; DOA based on line-spectra can effectively detect the target radiating line-spectra and estimate its azimuth angle; Bar graph approach can suppress line-spectra coherent interference and distinguish different targets radiating line-spectrum. Weighted bargraph approach can detect target in broadband coherent interference and estimate its azimuth angle.Finally, the thesis analyses the data of two trials in lake and sea, and estimator result of DOA and detector result by single vector hydrophone are presented, knowing that experiment result is basically consistent with theory result. It is shown in sea trail that one single vector hydrophone can detect target and estimate its azimuth in long range, the maximal range is up to 12km.