未知互耦条件下混合信号波达方向估计

阵列天线互耦对导向矢量的扰动以及信号相干性对数据协方差矩阵造成的秩损,使得基于子空间正交性原理的超分辨波达方向估计(Direction-of-Arrival,DOA)算法性能恶化,甚至失效。针对这一问题,提出一种在相干与非相干信号混合状态下无需阵列互耦补偿的特征矢量平滑DOA估计算法。该算法对部分阵元接收数据的协方差矩阵特征分解,将得到的特征矢量平滑处理后构造等效协方差矩阵,抑制阵列互耦影响的同时完成混合信号DOA估计。在阵列互耦和信号相干性均未知的条件下,正确估计了信号DOA,无需互耦参数估计或补偿。计算机仿真结果验证了算法的有效性。

DOA Estimation of Mixed Signals Under Unknown Mutual Coupling

Performance of high resolution direction-of-arrival (DOA) estimation algorithms based on the orthogonality ofsubspaces is degraded by array manifold perturbation resulted from mutual coupling (MC) and rank loss of covariance ma.trix caused by signal coherency. In this paper, an eigenvectors smoothing direction finding method, without any MC com.pensation, was proposed for coherent and non-coherent mixed signals under unknown MC. The method automatically sup.pressed the effects of unknown MC by an equivalent covariance matrix reconstructed through eigenvectors smoothing. TheDOAs of mixed signals could be estimated with the equivalent covariance matrix. Without any array calibration, the pro.posed algorithm achieved a favorable accuracy of DOA estimation under unknown MC irrespective of signal coherency.The simulation results demonstrated the validity of the proposed method.