基于可变对角载入的鲁棒自适应波束形成算法

Robust Adaptive Beamforming Algorithm Based on Variable Diagonal Loading

针对传统算法对方向向量偏差敏感的缺点,提出了一种基于可变对角载入的鲁棒自适应波束形成算法。为了提高算法的鲁棒性,采用非线性约束条件下的最优化阵列输出功率对信号方向向量进行优化求解,且优化解中的参量能够准确求出。为了减少计算量,采用递推算法求逆矩阵并利用泰勒级数展开,推导出基于可变对角载入的权重向量公式。该算法可有效地抑制方向向量偏差所带来的影响,降低了计算量易于实时实现,提高了系统的鲁棒性,改善了阵列输出的信干噪比,使其更接近最优值。仿真结果表明,该算法相对传统算法可以获得更好的性能。

The traditional algorithms are known to be very sensitive to slight mismatches between the presumed and actual signal steering vectors. In this paper,a novel approach based on the variable diagonal loading to robust adaptive beamforming is proposed. To improve robustness, the output SINR is minimized to obtain the signal steering vector including additional nonlinear constraints and the parameter in the optimal solution can be solved accurately. To decrease computation complexity, the recursive weight vector based on the variable diagonal loading is obtained by recursive least squares and Taylor series. The proposed algorithm reduces the influence of the mismatches, decreases computation complexity, develops online implementations, provides an improved robustness against the mismatches and makes the mean output array SINR consistently close to the optimal one. Simulation results are present to demonstrate that the performance of robust adaptive beamforming algorithm can outperform than that of the traditional algorithms.