Strong direct path interference suppression based on spatial filtering

Abstract

Strong direct path interference suppression is one of the problems to be solved in AUVs' cluster system which has the advantages of concealment, precision, anti-jamming capability and function distance. In order to estimate the target direction，3 methods of beamforming，including covariance matrix taper(CMT) condition，null-constrained condition and second-order cone programing(SOCP) constraint condition, are used to restrain direct path interference suppression separately in this paper. Comparing the 3 methods with simulation, SOCP gives the weights taking main lobe response, sidelobe level, depth, and width of zeros into consideration; null-constrained condition has a smaller amount of calculate and better anti-interference ability. But when the array disturbance exists, all the methods' performances are not good. Then, an improved algorithm is proposed to improve the tolerance of array disturbances.