Efficient method to determine diagonal loading value

It is well known that the performance of the adaptive beamforming algorithm is degraded when the sample support is short. The diagonal loading method is a simple and efficient method for improving the robustness of adaptive beamforming for such cases. Meanwhile, we are not aware of a formal approach to determine an optimal diagonal value to date. In this paper, we propose a data dependent method for the determination of the diagonal loading value. The proposed method makes a connection between the diagonal loading value and the estimation error of the estimated covariance matrix. The larger the estimation error, the larger the diagonal loading value. Thus, the proposed method adjusts the diagonal loading value according to the array data. In addition, this method is efficient in computation.