A method for suppressing strong near-field interference of large towed array

Abstract This paper addresses the challenge of diminished detection capabilities caused by strong near-field interference during the remote surveillance operations of large towed arrays. We introduce a method designed to suppress this near-field interference. By employing a spherical wave model to scan the near-field region, our approach obtains two-dimensional spatial spectrum estimations in terms of distance and azimuth, facilitating precise near-field localization. Utilizing the localization outcomes, we construct an orthogonal complementary projection space for the covariance matrix and project the array domain covariance matrix into this space, thereby eliminating the influence of near-field interference. Subsequently, we implement deconvolution beamforming based on the plane wave model to enhance remote surveillance capabilities. The efficacy of this method has been substantiated through both simulation and analysis of marine data. The findings demonstrate that our method is capable of mitigating interference under strong near-field conditions, effectively separating far-field targets, and improving the resolution of the spatial spectrum. Compared to traditional beamforming techniques, our simulation results indicate that the proposed method can achieve a background suppression capability of up to 5dB for the detection of far-field targets in the presence of near-field interference.