Power estimation based on robust Capon beamforming improved by matrix smoothing

Recent researches on diagonal loading beamforming are reviewed,and an improved Robust Capon beamformer is proposed.The algorithm can not only estimate the power and Direction-of-Arrival(DOA) of the incoherent signals but estimate those of the coherent signals as well,and also performs better under low SNR than the standard RCB.The basic idea of the improved RCB is to involve additional steps of the matrix smoothing and projecting the weights into signal-plus-interference subspace in the calculation.Simulations suggest a strong ability of the beamformer in separating coherent signals,power estimation and a 15dB～20dB sidelobe-depression as the input SNR at -10dB.Furthermore,the method is still effective when the estimated number of the signal sources is larger.