稀疏拉伸式L型极化敏感阵列的二维波达方向和极化参数联合估计

Joint 2D-DOA and Polarization Parameter Estimation with Sparsely Stretched L-shaped Polarization Sensitive Array

为降低现有的共心式矢量传感器阵列天线间存在的严重互耦影响,进一步提高参数估计精度,该文提出一种稀疏拉伸式L型极化敏感阵列(SSL-PSA),并针对该阵列提出一种2维波达方向(DOA)和极化参数联合估计算法。首先建立稀疏拉伸式极化敏感阵列的信号模型,然后将阵列划分为6个子阵,采用子空间旋转不变算法(ESPRIT)算法得到多个旋转不变因子(RIFs),再根据旋转不变因子间的关系,通过数学运算,得到一组方向余弦有模糊精估计值和4组无模糊粗估计值;然后重构出对应的4组导向矢量,根据导向矢量和噪声子空间的正交性,确定出正确的一组无模糊粗估计值;最后通过现有的解模糊方法得到高精度且无模糊的DOA和极化参数估计值。该文所提阵列不存在共心结构,相对于现有的含有共心式矢量传感器结构的阵列,大大降低了互耦影响,且可在不增加天线数目的前提下,有效扩展阵列的2维孔径,大大提高DOA估计精度。仿真结果证明该文所提方法的有效性。

In order to reduce the serious mutual coupling effect across the elements of the existing collocated vector sensor array and further improve the parameter estimation accuracy,a Sparsely Stretched L-shaped Polarization Sensitive Array(SSL-PSA)is proposed,and a novel method for estimating the azimuth-elevation angles as well as polarization parameters is presented accordingly.Firstly,the signal model of SSL-PSA is established.Then,the SSL-PSA is divided into 6 subarrays,thus the ESPRIT algorithm can be utilized to estimate the Rotational Invariant Factors(RIFs).On this basis,a set of fine but ambiguous estimates and four sets of unambiguous coarse estimates of direction cosine are obtained by a series of mathematical operations.Then,four corresponding steering vectors can be reconstructed and the correct coarse direction-cosine estimation can be determined according to the orthogonality of the steering vector and the noise subspace.Finally,the estimates of Direction-Of-Arrival(DOA)and polarization parameter can be achieved by the existing disambiguate method.Compared to the existing polarization sensitive array consists of collocated vector sensor,the proposed one has no collocated configuration,which can reduce the mutual coupling effect.Additionally,the proposed method can also extend the spatial aperture and refine the direction-finding accuracy without adding any redundant antennas.Simulations are carried out to verify the effectiveness of the proposed method.