基于变对角加载的RCB算法

RCB Algorithm Based on Variable Diagonal Loading

稳健的Capon波束形成(RCB)算法确定的加载量与设定的导向矢量误差范围成正比,在导向矢量误差比较小时,加载量也比较小,这时对小快拍的稳健性就很差。为了改善RCB算法在小快拍时的性能,提出一种基于变对角加载的RCB算法,利用估计的协方差矩阵误差对采样协方差矩阵进行修正,用修正后的协方差矩阵代替原协方差矩阵代入到RCB算法的权向量求解过程中,这样可以根据导向矢量误差和协方差矩阵误差动态调整加载量,在不增加计算复杂度的基础上,可以获得比RCB算法更好的稳健性。计算机仿真验证了算法的有效性。

The diagonal loading level of the robust Capon beamformer(RCB) is in direct proportion to the error range of steering vector.When the vector error is small,the loading level is low,so the RCB algorithm has little robustness to small snapshot number.In order to improve its performance in this situation,a modified RCB algorithm based on variable diagonal loading is proposed.The algorithm firstly calibrates the sample covariance matrix utilizing the estimated covariance matrix error,and then the calibrated covariance matrix is used for the RCB algorithm instead of the original one.The new algorithm can adjust the loading level dynamically according to both the steering vector error and the covariance matrix error,and provides more robust capabilities than the RCB algorithm while with the same computational complexity.Simulation results show the effectiveness of the proposed algorithm.