无人机高频电磁建模方法及应用研究

发布时间：2018-01-11 03:13

本文关键词：无人机高频电磁建模方法及应用研究　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：无人机的电磁散射特性研究在军事领域具有重要意义。因无人机是由介质材料和金属材料混合构成,所以在研究分析无人机的雷达目标特性时较一般PEC(Perfect electromagnetic conductor-理想电磁导体)目标复杂得多。基于计算电磁学方法,利用计算机仿真来获取目标散射特性已成为国内外雷达研究者高度关注的问题,本文仿真研究了雷达目标高分辨率一维距离成像和聚束合成孔径雷达(Spotlight SAR)二维成像。在电磁问题分析方法中,高频近似方法较数值算法占用的计算资源少,计算速度快,是处理介质-金属混合目标散射的有效方法。本文基于含目标实体部件分解的高精度几何建模方法,利用射线追踪,提出了空间射线分集技术,射线分集技术运用混合的几何光学-物理光学(GO-PO)法,计算各射线子集的散射贡献,然后将散射子集按RCS的贡献大小进行排序并选出目标强散射来源,最后运用属性散射中心模型,提出了一种正向的介质-金属混合目标散射中心参数化建模方法。机翼是无人机中最复杂的结构,故本文首先重点研究无人机机翼结构的电磁特性,然后给出无人机高频电磁建模结果。本文的主要内容包括:(1)发展了用于介质-金属混合目标的高频电磁散射预估的混合GO-PO方法,在此基础上,研究了目标雷达仿真成像。介绍了高分辨率一维距离成像原理以及聚束SAR二维成像原理,仿真了简化机翼1的二维成像,与目标几何模型对比,验证仿真结果的准确性与有效性,得到了满意的结果。(2)基于空间射线分集,发展了适用于介质-金属混合目标强散射来源判定及分析方法。以简化机翼目标为研究对象,研究了简化机翼强散射源在不同姿态角下的分布情况。(3)发展了适用于介质-金属混合目标的正向的参数化建模方法。将简化机翼目标作为研究对象,在不同姿态角下,建立目标正向的参数化模型。将简化机翼的参数化重建SAR图像与其仿真SAR成像进行比较,得出简化机翼在不同姿态角下主要的散射来源;结合无人机暗室测量数据,预估得到了无人机参数化重构SAR成像。(4)对参数化建模成像进行了相位修正和位置修正。将修正前后的结果与仿真SAR图像作比较,证明了经相位修正、位置修正后的参数化建模成像更能准确的反映目标的电磁特性。
[Abstract]:The study of electromagnetic scattering characteristics of UAV is of great significance in military field, because UAV is composed of dielectric materials and metal materials. Therefore, the radar target characteristics of UAV are compared with that of PEC(Perfect electromagnetic conductor (an ideal electromagnetic conductor). The target is much more complex. Based on computational electromagnetics. Radar researchers at home and abroad have paid close attention to using computer simulation to obtain the scattering characteristics of targets. In this paper, high-resolution one-dimensional range imaging and Spotlight SAR two-dimensional imaging of radar targets are simulated. The high frequency approximation method is an effective method to deal with the scattering of dielectric and metal mixed targets because of its less computational resources and faster computation speed than the numerical method. This paper is based on the high precision geometric modeling method which includes the decomposition of the target solid parts. The space ray diversity technique and the hybrid geometric optical-physical optics (GO-POO) method are proposed to calculate the scattering contribution of each subset of rays by ray tracing. Then the scattering subset is sorted according to the contribution of RCS, and the target strong scattering source is selected. Finally, the attribute scattering center model is used. In this paper, a parameterized modeling method for the scattering center of a mixture of dielectric and metal targets is proposed. The wing is the most complex structure in UAV, so the electromagnetic characteristics of wing structure of UAV are mainly studied in this paper. The main contents of this paper include: 1) A hybrid GO-PO method is developed to predict the high frequency electromagnetic scattering of dielectric metal mixed targets. The principle of high-resolution one-dimensional range imaging and the two-dimensional imaging principle of spotlight SAR are introduced. The two-dimensional imaging of the simplified wing 1 is simulated and compared with the geometric model of the target. The accuracy and validity of the simulation results are verified and satisfactory results are obtained. A method for determining and analyzing the source of strong scattering from dielectric and metal mixed targets is developed, and the simplified wing target is taken as the object of study. In this paper, the distribution of the strong scattering sources of the simplified wing at different attitude angles is studied. The forward parameterized modeling method suitable for the dielectric metal mixed target is developed. The simplified wing target is taken as the object of study. At different attitude angles, the forward parametric model of the target is established, and the simplified wing parameterized reconstructed SAR image is compared with its simulated SAR image. The main scattering sources of the simplified wing at different attitude angles are obtained. Combined with UAV darkroom measurements. The parameterized reconstruction of UAV SAR imaging. 4) the phase correction and position correction of parameterized modeling imaging are carried out. The results before and after the correction are compared with the simulated SAR images. It is proved that the parameterized modeling imaging with phase correction and position correction can reflect the electromagnetic characteristics of the target more accurately.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.52

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