基于波束域导向矢量估计的稳健自适应波束形成方法

针对导向矢量失配和样本协方差矩阵估计误差导致自适应波束形成性能下降的问题，该文提出一种基于波束域导向矢量估计的稳健方法。该方法首先利用期望信号角度失配区域的补集构造波束域转换矩阵，克服了当样本协方差矩阵中存在期望信号分量时现有算法出现有用信号对消的缺点。其次推导出波束域导向矢量估计方法，并将其转化为包含恒模约束的非凸二次约束二次规划问题，然后采用半正定松弛规划估计实际的波束域导向矢量。计算机仿真验证了该文所提方法的有效性。

Robust Adaptive Beamforming Based on Beamspace Steering Vector Estimation

In order to solve the problem of performance degradation due to the imprecise knowledge of the array steering vector and inaccurate estimation of the sample covariance matrix. A new approach based on beamspace steering vector estimation for robust adaptive beamforming is presented in this paper. Firstly, by using the complementary set of the spatial sector in which the actual steering vector lies, beamspace transformation matrix can be constructed to ensure that the signal of interest is removed from the sampling covariance matrix. Then a method for beamspace steering vector estimation is derived, and mathematically expressed as the nonconvex Quadratically Constrained Quadratic Programs (QCQP) problem with one non-convex quadratic equality constraint, which can be successfully solved by using SemiDefinite Relaxation (SDR) techniques. Simulation results show the effectiveness of the proposed algorithm.