Robust Beamforming Algorithms

Beamforming is widely studied in array signal processing fields because it can completely receive the desired signal and suppress the interference signals simultaneously in the increasingly complex electromagnetic environment. Robust beamforming usually offers a more robust beam than the conventional beamforming methods when the prior information is not sufficient. Therefore, robust beamforming is studied widely all over the world.The paper focuses on the problem of improving the robustness of beam and studying beamforming algorithms based on the constraints.It mainly comprises:1、Several classic beam optimal criterion are studied and compared. The performance of standard Capon beam is analyzed when the desired direction errors exist. The study of the diagonal load algorithms and the reason why the diagonal load can improve beam robustness are also discussed.2、Three robust adaptive beamforming algorithms are studied, which are robust Capon beamformer (RCB), robust Capon beamforming with double constraints, robust Capon beamforming with norm constraint respectively. The performance of each algorithm is analyzed in the paper.3、A more robust beamforming algorithm named robust Capon beamforming with orthomodular constraint is proposed. It utilizes the orthogonality of matrix and norm constraint which can make the desired signal be better received.4、An interference suppression algorithm base on Least Squares is proposed after analyzing the conventional satellite interference suppression algorithms. It can suppress interferences, meanwhile, ensure the gain of desired directions. So, it can receive useful signals effectively.5、A widely linear robust beamforming is proposed after analyzing the characteristics of satellites signal. It uses the noncircular characteristic to expand the received data. So, the array aperture is expanded. The proposed algorithm can get narrower mainlobe width, more accurate mainlobe direction, deeper nulls of the interferences.At last, simulation results confirm the effectiveness of the proposed algorithm.