Vector Array Adaptive Beamforming Under Platform Noise Interference

With the improvement of vibration and noise reduction technology in the design of surface combatant and submarines,the intensity of radiated noise is reduced,which requires sonar systems to have better detection performance.Vector signal processing technology is widely used for its good low-frequency detection and anti-interference performance.For vector towed linear arrays and vector submarine head cylindrical arrays installed on ship platforms,they are inevitably affected by platform noise when receiving target signals,and vector towed arrays are also affected by towed linear array noise.Moreover,there will inevitably be errors in the position of each array element in the array,resulting in a decrease in the robustness of the minimum variance distortionless response(MVDR).Therefore,when estimating the azimuth of far-field targets using vector towed linear array and vector submarine head cylindrical array,the influence of platform noise and steering vector error should be minimized as much as possible.For the vector towed linear array,this paper first simplifies the platform noise model according to the spatial distribution characteristics and spectral characteristics of the platform noise,and analyzes the flow noise characteristics of the towed linear array,so as to obtain the independent processing model of sound pressure vibration velocity and the(p+v_c)·v_c joint processing model when the far field target azimuth estimation of the vector towed linear array.The performance of vector linear array MVDR and robust Capon beamforming(RCB)algorithms in the presence of steering vector error was analyzed through simulation.Secondly,aiming at the strong interference caused by the far-field platform noise incident from the end-fire direction on the azimuth estimation of the far-field signal of the vector towed linear array,the performance of the spatial matrix filter with three different criteria is analyzed,and the optimal spatial matrix filter of the vector towed linear array is the overall constraint matrix filter with stop-band response,and the strong interference suppression ability of the optimal spatial matrix filter is verified by simulation.Furthermore,since the towed linear array flow noise received by the vector towed linear array has the characteristics of spatial non-correlation,this paper uses the inhomogeneous diagonal unloading algorithm to suppress it,and the simulation verifies the flow noise suppression ability of the inhomogeneous diagonal unloading algorithm under different conditions.Finally,by combining the optimal spatial matrix filter and inhomogeneous diagonal unloading algorithm of the vector towed linear array,the noise suppression of the vector towed linear array at different snr and different drag speeds is realized,and the most suitable(p+v_c)·v_c joint processing RCB algorithm for towed line array azimuth estimation was obtained.For the vector submarine head cylindrical array,this article first simplifies the model based on the spatial distribution of platform noise,obtains independent signal processing models and joint processing models,and analyzes the performance of the vector cylindrical array MVDR and RCB adaptive beamforming algorithm when there is steering vector error through simulation.Secondly,in response to the strong interference caused by near-field mechanical noise and propeller noise incident from the large sector in the middle and rear of the ship to the bow array in the far field signal estimation,by analyzing the performance of spatial matrix filters with different criteria,it is found that the combination of the stopband response zero constrained spatial matrix filter and MVDR algorithm is more suitable for near-field noise suppression of the submarine head cylindrical array.