目标全极化散射特性研究

发布时间：2019-03-20 21:13

【摘要】：全极化雷达系统是目前雷达学界的热门研究方向,人们希望利用电磁波的极化特性拓展雷达系统接收的信息量来提高信噪比,准确探测和识别目标。雷达目标极化散射特性建模以及表征是空中目标探测研究中的基础性内容。在本文的研究工作中,基于混合场积分方程进行了目标散射问题的数值建模,首先对简单目标线极化基下全极化远场散射进行了计算分析。根据典型目标的电磁散射中交叉极化散射强度远低于主极化散射的情况,分析了简单反射器的全极化散射矩阵,得到目标强交叉极化散射的激励条件,并且对新型的交叉极化散射定标体进行了数值建模计算。文中对飞机目标的一些结构进行了散射分析,比较了隐身目标和非隐身目标在电磁谐振状态下全极化散射特性的差异,计算了两种典型无人机的极化散射特性。本文对有多种反射器的组合体目标和无人机模型进行了逆合成孔径雷达成像,交叉极化像和主极化像的不同反映了目标不同结构极化散射机理的差异。文中采用基于全极化一维和二维回波模型的超分辨方法对无人机目标的强散射点位置进行了提取与对比,得到了无人机目标的二维超分辨像。本文也对位于自由空间和海面上方的二面角反射器的散射特性做出了分析。最后本文根据之前得到的无人机强散射点位置,提取了它们的散射矩阵。结合经典的最优极化理论,本文考察了无人机目标强散射点的极化功率响应图。通过对这些散射点极化功率响应的分析,本文得出了极化雷达能够更好地探测识别空域目标的结论。
[Abstract]:Full polarization radar system is a hot research direction in radar field at present. It is hoped that the information received by radar system can be expanded by using the polarization characteristics of electromagnetic wave to improve signal to noise ratio and to detect and identify targets accurately. The modeling and characterization of polarimetric scattering characteristics of radar targets are the basic contents in the research of aerial target detection. In the research work of this paper, the numerical modeling of target scattering problem based on the mixed field integral equation is carried out. Firstly, the full polarization far-field scattering of a simple target is calculated and analyzed. Based on the fact that the cross-polarization scattering intensity of a typical target is much lower than that of the main polarization scattering, the full polarization scattering matrix of a simple reflector is analyzed, and the excitation conditions of the strong cross-polarization scattering of the target are obtained. And the numerical modeling of the new cross-polarization scattering calibration body is carried out. The scattering characteristics of stealth target and non-stealth target in electromagnetic resonance state are compared, and the polarization scattering characteristics of two typical UAV are calculated. In this paper, inverse synthetic Aperture Radar (AAR) imaging of combined target and UAV model with multiple reflectors is presented. The difference of cross-polarization image and main polarization image reflects the difference of polarization scattering mechanism between different structures of target. In this paper, the super-resolution method based on full polarization one-dimensional echo model and two-dimensional echo model is used to extract and compare the position of strong scattering point of UAV target, and the two-dimensional super-resolution image of UAV target is obtained. The scattering characteristics of dihedral corner reflector located in free space and above sea surface are also analyzed in this paper. Finally, the scattering matrix of UAV is extracted according to the position of strong scattering point of UAV. Combined with the classical optimal polarization theory, the polarization power response diagram of the target strong scattering point of UAV is investigated in this paper. By analyzing the polarization power response of these scattering points, this paper draws the conclusion that polarimetric radar can detect and identify spatial targets better.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN958

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