Study On Target Recognition Algorithm Of Parametric Array Sonar

As new submarines are in active service in countries, their radiation noise get lower and lower; In addition, the noise of marine environment is particularly complex, especially in shallow waters;And the acoustic warfare technology becomes more and more advanced, they brought great difficulties to the target detection and identification of sonar. Because of broadband acoustic parametric array technology can solve the problem of multipath interference in shallow water; its transmission beam has the characteristics high directivity, high-bandwidth and narrow beam, which can significantly improve the performance of active sonar target recognition. But as computer technology becomes more and more modern, the intelligent level of sonar also needs to improve. The target recognition capability of sonar system is an important indicator of performance, which is still a headache problem of modern sonar technology. Therefore, the purpose of this paper is to develop the automated target recognition technology of parametric array sonar, to improve the rapid reaction capability and target identification capabilities of parametric array sonar.Firstly, described the nonlinear acoustic principles of parametric array sonar, and elaborated the process of nonlinear interaction between in two acoustic signal; and derived the principle of emission and receiving of acoustic parametric array, the transmitting array and the receiving array are utilized nonlinear interaction; designed a set of the transmitting and receiving systems which based on parametric array.Secondly, analysised the theory of goal highlights model, and established a highlights model of submarine, and got the total echo signal model; Each individual highlight can be described by the three parameters of echo signal: signal delay, amplitude and phase. By Accumulating the echo of all the highlights to obtain the total target echo signal, and do its Matlab simulation waveforms; Then, using the frequency discrete wavelet transform(FDWT) to process the echo signal, and extracting target highlights features, and do its Matlab simulation.Once more, by extracting the pole from echo signal to identify target. Using Correlation processing algorithms and matrix pencil algorithm to extract poles, analyzing the results of the echo signal after correlation processed; using matrix pencil algorithm to extract poles from the cross-correlation results; Using training signal as an input signal of this algorithm and doing the Matlab simulation, by the results value to determine the reliability of the algorithm.Finally, using the resonance scattering signal in echo signals to achieve target identification. By analyzing the theory of resonance scattering and the composition structure of the echo signal, resonance scattering signal is located in the scattering wave of echo signals; designing the separation algorithm which using time delay and adaptive filtering algorithm as the core; using this separation algorithm to separated resonance scattering signals from the target echo signals of elastic target or inelastic target; Comparing and analysing the experimental results, shows that: this method can achieve the classification of target.