Fully automatic computation of diagonal loading levels for robust adaptive beamforming

One of the most well-known robust adaptive beamforming approaches is diagonal loading. However, there are usually no clear guidelines on how to choose the diagonal loading level reliably. In this paper, we present algorithms that can compute the diagonal loading level fully automatically from the given data without the need of specifying any user parameters. The proposed diagonal loading algorithms use shrinkage-based covariance matrix estimates, instead of the conventional sample covariance matrix, in the standard Capon beamforming formulation. The performance of the resulting beamformers is illustrated via numerical examples and compared with other adaptive beamforming techniques.