正交模约束的稳健波束形成算法

Robust Capon Beamforming with Orthomodular Constraint

Capon波束形成算法在导向矢量存在误差或是在较少快拍数或高信噪比情况下,都会使波束产生严重的畸变。为了提高波束的稳健性,该文提出了一种正交模约束的稳健波束形成算法(OCCB),并通过二次求导得到阵列权值的具体数学表达式。该算法在Capon算法的基础上,增加对阵列权值和噪声子空间的正交模约束,实现了在不影响信号和干扰特征值的同时,完成对噪声特征值的加载,减小噪声特征值的扩散程度。分析了部分对角加载对期望信号、干扰和噪声的影响。该算法在导向矢量存在误差、采样快拍数较少和高信噪比情况下,都可使波束具有更低的旁瓣和更加准确的主瓣指向,同时对干扰能进行较好的抑制,仿真结果证实了方法的有效性。

Standard Capon beamformer has serious distortion in the small snapshot or steering vectors mismatched or high SNR.In order to improve the robustness of beam,a robust Capon Beamforming with Orthomodular Constraints algorithm（OCCB） is proposed,through the second derivative get the accurate mathematical expression of weights.The algorithm restrains the orthogonality of array weight and noise subspace in the base of Capon,achieving diagonal loading of noise eigenvalue,decreasing spread level of noise eigenvalue.The influence of partly diagonal loading to the desired signal,interference and noise is analyzed.In the small snapshot or steering vectors mismatched or high SNR,this algorithm can make beam get lower sidelobe and more accurate mainlobe direction.Meanwhile,the interference can be better suppressed.Simulation results confirm the effectiveness of the proposed algorithm.