Research On Robust Beamforming Technology Based On Towed Array

A towed array sonar is a system of hydrophones towed behind its carrier on a cable.It has been widely used in the military field of underwater target detection and commercial marine strata analysis,oil and gas exploration and other fields.The DOA estimation is the core function of the towed array target detection.However,due to the characteristics of towed array itself,shape distortion and flow noise have to be considered.Robust beamforming technology is needed in towed array DOA estimation.This paper analyzes the basic principle of some kinds of towed array beamforming algorithm,focusing on the performance analysis of adaptive beamforming algorithm under special circumstances.This paper designed an array shape reconstruction algorithm based on heading sensor.This paper adopts the convex optimization method for MVDR beamforming algorithm.Simulation analysis and data processing results prove that convex optimization technology MVDR beam forming algorithm is superior to the conventional MVDR algorithm in detection ability.The main work and innovation of this paper are as follows:I.Analyzed the influence of array channel amplitude and phase errors and limited number of snapshots on MVDR beamforming.With the increase of amplitude and phase errors and the decrease of the number of snapshots,the mainlobe width and sidelobe height increase,reducing the accuracy of direction finding.II.Towed array shape reconstruction algorithm based on heading sensor and polynomial fitting was proposed to solve the problem of towed array shape distortion.Join heading sensors into towed array and get angle information of certain points,and the function of angle value and array length can be found using polynomial fitting.Finally integral calculation obtains the location information of each element of the array.The simulation results show that the algorithm improved towed array beamforming target direction finding accuracy under typical shape distortion circumstances.III.The convex optimization method is applied to the weight optimization of MVDR algorithm,and the convex optimization algorithm is derived.The results of simulation and experimental data processing show that the improved MVDR algorithm has better performance in the beamforming direction finding.