An Improved Scheme to Suppress Coherent Interference in LCMV Adaptive Array

When the interference and desired signal are coherent, performance of the linearly-constrained-minimum-variance-criterion (LCMV) based adaptive array will degrade dramatically. Conventional uniform spatial smoothing (USS) has poor ability to suppress coherent interference, and it will reduce the array aperture. In the paper, an improved scheme to suppress coherent interference is proposed. Firstly, the paper presented an adaptive weighted-spatial-smoothing (WSS) algorithm, which can de-correlate the coherent interference effectively. Then, based on WSS and the LCMV criterion, the optimum weight vector of subarray beamformer can be obtained. Lastly, considering the phase relationship between each subarray, an approach for full array beamforming is proposed. The scheme greatly improves the array´s ability to suppress coherent interference and avoids the loss of aperture caused by conventional spatial smoothing. Theoretical analysis and computer simulation confirmed the availability and robustness of the algorithm