Vector Signal Processing Based On Small Moving Platform

The direction of arrival is of great importance in underwater signal processing. The vector-sensor can simultaneously measure pressure and particle velocity. The particle velocity filed is vector, and its direction is the direction of target. So we can get the azimuth angle of a target with a single vector-sensor. For locating the target, big hydrophone array must be constructed if using the traditional acoustic pressure hydrophone. Also, the usual self-guiding system which merely makes use the pressure information can measure the target direction only when its dimension is bigger than half of wavelength. Then some small system must work in status of high frequency. Because of its severe attenuation, the operating range of system is limited. The vector sensor can work in status of low frequency which has small transmission attenuation and is free of water condition so it is able to operate far away.The dissertation works in backgrounds of small moving system. On basis of signals received by vector-sensor, the thesis discusses five methods of azimuth estimation, and their principles are analyzed and simulated by computer. For the different condition of method, different azimuth estimation is selected by the signal and noise. The dipole and combined directivity are studied. Acoustic pressure and particle velocity combined processing can form the single side directivity, which is functionary to suppress the coherent interference. And it is the base of selecting reference signal in adaptive noise cancelling.Two methods of noise canceling based on vector sensor are set forth according to the reference signal. They can increase the signal delectability and the accuracy of azimuth estimation. The computer simulations are done and the results are analyzed for both methods.