抗主瓣干扰的平移不变子阵干涉测角方法

Interferometric DOA Estimation Based on Shift Invariance Subarrays for Suppressing Mainlobe Jamming

针对存在主瓣干扰时的目标波达方向(DOA)估计问题,提出了一种利用子阵平移不变性的自适应干涉测角方法。首先,将面阵划分成经过平移能重合的上、下子阵;其次,用训练样本估计上、下协方差矩阵,各自经特征分解后获得特征矢量;然后,通过主特征矢量空间构造上、下子阵的干扰正交补空间,将波束指向的导向矢量向干扰正交补空间投影,得到子阵抗干扰权;接着,利用上、下子阵自适应干扰抑制后的输出在子阵级通过干涉测角获得目标俯仰角估计;最后,对方位维做类似处理,获得方位角估计。数学推导证明干涉测角与自适应波束畸变无关。与其他方法相比,该方法具有更好的抗干扰性能与更佳的测角性能。实测和仿真数据的处理结果显示了该方法的有效性及优越性。

To deal with the problem of target direction of arrival （~DOA） estimation in the presence of mainlobe jamming, a novel method for adaptive interferometric DOA estimation by using subarray shift invariance has been proposed. First, the planar array is divided into up and down subarrays satisfying that one can be overlaped to the other by shift; second, the co- variance matrices corresponding to up and down subarays are calculated with training samples and eigenvectors are obtained by eigen decompositions of the two covariance matrices, respectively~ third, adaptive up and down weight vectors are ob- tained by the projection of beam direction vector onto orthogonal subspaces of interfences, respectively~ fourth, elevation angle can be estimated by interferometric processing between up and down outputs of anti-jamming~ finally, azimuth angle can be achieved by similar processing between right and left subarrays. It is proved that DOA estimations have nothing to do with adaptive beam distortions. Compared with other methods, the proposed method has a better performance of interfer- ence suppression and a higer precision of DOA estimation. Results of measured and simulated data demonstrate the effec- tiveness and superiority of the proposed method,