双正交电磁矢量阵列低角估计方法研究

摘要

电磁矢量阵列由于利用了信号的极化信息,能显著提高阵列的环境感知性能.建立双正交电磁矢量阵列低仰角测高多径模型,提出利用极化平滑与空间平滑结合的预处理方法对直达波和多径进行解相干,同时利用极化和空域信息提高低仰角角度估计性能;并推导低仰角多径模型下双正交电磁矢量阵列的Cramer-Rao界,分析极化参数对测角性能的影响.仿真实验结果表明,低角情形下电磁矢量阵列相较于标量阵列测角性能更优;所提的极化空间平滑算法由于结合了极化平滑和空间平滑的优点,较现有方法解相干效果更好,精度更高,特别适用于直达波和多径极化状态差异较小的低仰角情形.%The electromagnetic vector-sensor array could significantly enhance the performance of environment sensing by utilizing the polarization information.In this paper,the multipath model of low angle target for double orthogonally oriented electromagnetic vector-sensor array is proposed.Moreover,to improve the performance of the estimation of the direction of arrival (DOA) for low angle targets with polarization and spatial information simultaneously,polarization smoothing and spatial smoothing are combined to decorrelate the direct signal and multipath signal.Furthermore,the Cramer-Rao bound of double orthogonally oriented electromagnetic vector-sensor array for low angle tracking is derived to analysis the influence of the polarization parameter for the performance of the estimation of directional of arrival.Simulations indicate that electromagnetic vector-sensor array considering the polarization information has advantages over the scalar array on the performance of DOA estimation.Because the proposed polarization-spatial smoothing algorithm takes advantages of polarization smoothing and spatial smoothing simultaneity,it outperforms the methods the state of the art,especially in the low-angle scenario that the direct signal and the multipath signal have little difference in polarization domain.