稳健自适应波束形成算法综述

Review of Robust Adaptive Beamforming Algorithms

标准Capon波束形成器(SCB)通过最小化波束输出功率,同时约束期望信号无失真输出以达到最大化输出信干噪比,但标准Capon波束对模型失配误差非常敏感,如来波方向估计误差、阵列扰动、目标运动等因素引起导向矢量误差,短快拍数据会引起协方差矩阵估计不准确。这些失配会引起波束形成输出信干噪比性能下降。为了提高Capon波束形成算法的鲁棒性,提出诸多稳健自适应波束形成算法,主要解决方案是对期望信号导向矢量和干扰加噪声的协方差矩阵进行修正。介绍标准Capon波束形成的信号模型及误差对其输出信干噪比的影响;从影响自适应波束形成性能的两个因素即协方差矩阵和期望信号导向矢量,对稳健自适应波束形成典型算法进行综述;对几种典型稳健自适应波束形成算法进行了仿真实验,结果表明所提算法的有效性,并对研究方向进行了展望。

The standard Capon beamformer(SCB)maximizes the output SINR by minimizing the beam output power and constraining the undistorted output of the desired signal.However,the standard Capon beam is very sensitive to model mismatch errors.Direction of arrival estimation error,array disturbance,target motion and other factors cause steering vector error;Small snapshot data will cause inaccurate estimation of covariance matrix.These mismatches will lead to the degradation of beam forming output SINR performance.In order to improve the robustness of Capon beamforming algorithm,many robust adaptive beamforming algorithms were proposed.The main solution was to modify the expected signal steering vector and the covariance matrix of interference plus noise.This paper first introduced the signal model of standard Capon beamforming and the influence of error on its output signal to interference noise ratio;Then,the typical robust adaptive beamforming algorithms were reviewed from two aspects that affected the performance of adaptive beamforming,namely,covariance matrix and expected signal steering vector;Finally,several typical robust adaptive beamforming algorithms were simulated.The simulation results showed the effectiveness of the proposed algorithm,and prospects for further research.