一种改进的正交投影自适应波束形成器

在酉变换的基础上，提出了一种改进的正交投影波束形成方法。新算法通过酉变换，将复值协方差矩阵变为实值矩阵，然后对其进行特征分解和波束形成，所需运算量约为正交投影算法的1/4。由于实值矩阵的计算过程中具有协方差矩阵前和后向平均作用。等效于采样快拍数加倍，因此，新算法可提高小声拍数和干扰源靠得较近时波束形成器的稳健性，增强输出信号干扰噪声比，此外，空间平滑作用还可去相关，使新算法在空间存在相关或者相干干扰时仍具有较好的干扰抑制性能和波束保形能力。计算机仿真结果说明了新方法的有效性。

An improved adaptive beamformer via orthogonal projection

Based on a unitary transformation, an improved adaptive beamforming via orthogonal projection is proposed. The new algorithm transforms a complex valued covariance matrix into a real valued matrix by means of a unitary transformation, and then eigen decomposes the transformed matrix for adaptive beamforming. The overall computational load is only about one fourth that required by the original orthogonal projection method. At the same time, due to the existence of the forward bakcward averaging effect which is equivalent to doubling the number of snapshots during the course of the computation for the real valued matrix, the new method may upgrade the robustness in the case of the small number of snapshots and closely spaced jamming sources, and raise the output signal to interference plus noise ratio. Additionally, the spatial smoothing can decorrelate possibly correlated source pairs, and therefore, the method presented has the advantages of the better performance of jammer suppression and stronger ability to reshape the beam over the orthogonal projection and sample matrix inversion algorithms in scenarios with partially correlated or fully coherent sources. The computer simulations demonstrate the effectiveness of the proposed method.