The Influence And Fitting Research Of Target's High Velocity To The Vector Signal Processing

The vector hydrophone (VH) can synchronously measure sound pressure and particle velocity at the same location in acoustic field, which is possible to improve performance of traditional underwater acoustic systems and broaden signal processing space. It has many advantages such as good directivity at low frequency and strong ability to immunize isotropic noise and can provides new ideas and methods for solving practical underwater acoustic engineering problems. With VH's maturity in technology and military demands, the VH is widely applied in all fields of underwater acoustic engineering, at present, it has become one of the most active research direction of underwater acoustic technology.Taking the application of vector hydrophone in underwater platform as the research background, this thesis makes efforts to resolve the problems of underwater high-speed moving target recognition and tracking. With a mathematic-physical model of underwater target's velocity established, deduced and tested, two kinds of algorithm to generate Doppler signals are proposed—fitting interpolation algorithm(FIA) and time inversion algorithm(TIA). And then the influence of target's high velocity on the vector signal processing is analyzed quantitatively and qualitatively.In order to abate the impact of target's high velocity, a matched algorithm is raised—instantaneous correlation integral algorithm(ICIA). Based on the measurement model of vector hydrophone, not only the principle and application of this algorithm is introduced systemically, but also its performance is investigated by a great deal of theoretical analysis and simulation. Studies show preliminarily that: this algorithm can eliminate the impact of the Doppler effects, suppress the cross-terms' interference, and improve signals SNR effectively. Therefore, preferable performance on many aspects such as targets features detection and targets recognition is achieved.Finally, a new kind of algorithm for DOA estimation is built with the combination of ICIA and reciprocal spectrum acoustic intensity(RSAI)—the WVD algorithm based on the correlation and the reciprocal spectrum(CRWVD). Instances under the conditions of different speeds, different distances and different SNR are tested by simulation researches, and the outcome is compared with RSAI and the Cramer-Rao bound(CRB). The results showed that the performance on DOA estimation of two algorithms is basically the same when the target is at the state of longer distance and low speed, but CRWVD is much better than RSAI when the target is at a closer range and high speed state.