一种基于对角载入的鲁棒MVDR波束形成算法

当信号方向向量精确已知时,传统最小方差无畸变响应(MVDR)波束形成算法具有较好的分辨率和抗干扰能力.在实际通信环境中,由于外部环境、天线阵列以及采样协方差矩阵的估计误差等因素的影响,导致传统MVDR波束形成算法的性能急剧下降.针对这一问题,本文提出了一种新的基于对角载入的鲁棒MVDR波束形成算法.该算法考虑信号方向向量的偏差对MVDR算法性能的影响,并在最大允许偏差范围内导出最优的权重向量,有效地抑制了偏差对输出性能的影响,具有很强的鲁棒性,从而能够适应复杂的通信环境;同时该算法采用递推算法避免矩阵求逆,降低了计算复杂度,便于工程实现.仿真实验表明,与传统MVDR算法相比,所提算法具有更好的输出性能。

A Robust Adaptive Beamforming Algorithm Based on Diagonal Loading

The MVDR beamformer has better spatial resolution and better interference rejection capability than the standard beamformer,provided that the signal steering vector is accurately known.However,in practical applications,the performance of MVDR beamformer degrades severely because of violation of underlying assumptions on the environment,sensor array and sample covariance matrix errors.To overcome the mismatches,a robust MVDR beamforming algorithm based on the diagonal loading was proposed.By considering the bad effect of steering vector errors on MVDR algorithm performance,and obtaining the optimal weight vector under the condition of the largest deviation,this algorithm can sufficiently reduce the effect of the mismatches and provide an improved robustness in the communication environment.Also,the algorithm uses a recursion process to avoid inversing matrix,which reduces the computational complexity and facilitates project implementation.The simulation results show that the proposed robust algorithm has better performance than the traditional MVDR algorithm.