波束空间能量约束的稳健自适应波束形成

Robust adaptive beamforming based on beam space power constraint

为改善波束形成器在一定失配条件下的工作性能,提出了一种稳健自适应波束形成方法。该方法通过设计信号在波束空间能量分布的约束条件,利用阵列数据协方差矩阵,结合迭代二阶锥规化方法,实现信号驾驶向量的估计,最后利用该估计得到最小方差无失真响应波束形成器。该方法在较恶劣的失配条件下也可以自适应地准确估计信号驾驶向量并保证其成分无失真地通过,使系统的稳健性得到改善。数据仿真结果表明,该方法在理想条件下与成熟的对角加载法性能相当,在失配条件下则优于后者。

In order to improve the performance of adaptive beamformer in the presence of steering vector mismatch, a robust adaptive beamforming method is proposed. In our method, the Minimum Variance Distortionless Response （MVDR） beamformer is designed on the basis of signal steering vector estimation, which is obtained adaptively from array data covariance matrix with beam space power constraint by the use of iterative second-order cone program. It is shown that steering vector of signal can be accurately estimated even when severe mismatch exists, which ensures that signal component will pass through without distortion. As a result, the robustness of beamformer is improved. Simulation result shows that performance of proposed method is close to the existing method using diagonal loading in ideal condition and better than the latter when mismatch exists.