Research On Adaptive Beamforming Technology Under Coherent Interferences

Adaptive beamforming technology is widely used in the area of radar, communication,sonar and other areas which need to use the array signal processing. The conventional adaptive beamforming has good performance, but the performance of conventional adaptive beamforming degrades severely and it can't suppress coherent interferences when there are coherent interferences or artificial intelligence interferences. So the study of the adaptive beamforming which can suppress coherent interferences has great significance.In view of the traditional Toeplitz algorithm which causes the energy leaking out from signal space to noise space , the larger estimation bias and the distortion of adaptive directivity diagram, this paper studys the improved Toeplitz algorithm (ITOP) which is based on the ESB algorithm and linear constrained minimum variance beamforming. The algorithm uses relevance vectors to reconstruct array data covariance matrix, then use the ESB algorithm and the rule of LCMV to beamform. The MATLAB simulations clearly demonstrate that the introduced ITOP algorithm has better performance in the environment of low input SNR and small snapshot, less calculation and faster speed of the algorithmin without array aperture loss.In view of conventional space smoothing method can't completely remove coherence with the loss of array aperture, the full array of weighted extended spatial smoothing algorithm (Full-WESS) is studied by combining with the advantages of adaptive weighted spatial smoothing algorithm. The algorithm combines array extension with weighted spatial smoothing and the technology of full array convertion to suppress coherent interferences. The MATLAB simulations clearly demonstrate that the Full-WESS algorithm has higher output SINR and more effective estimation performance for coherent source, and isn't very sensitive to the angle difference between the desired signal and interference signal.