【作者】 李良超；

【导师】 吴振森；

【作者基本信息】 西安电子科技大学 ， 无线电物理， 2007， 博士

【摘要】 本文受到多个国防预研项目的资助,主要完成了以下几方面的工作：在分析了人工神经网络的基本理论基础上,提出了使用BP神经网络建立BRDF模型的方法,建立了多种材料激光波段2维、3维BRDF模型和某材料的含波长信息BRDF模型。结果表明神经网络模型具有精度高,适应范围广等的特点。针对实际目标大多由不同表面材料组成的特点,建立了含材料信息的复杂目标几何模型,提出计算覆盖多种材料LRCS的可视化计算方法。设计并完成了光学特性计算软件包。计算了大量空中、地面目标覆盖不同材料、多种运动姿态下的LRCS角分布曲线,并对结果进行了分析讨论。测量了某脱漆严重的靶机的后向LRCS角分布,计算了该目标使用蒙特卡罗方法模拟不同脱漆情况下的LRCS,估计靶机的脱漆程度。基于缩比理论和测量方法,研究复杂目标LRCS的缩比关系。通过对F16等飞机的缩比模型的测量和全尺寸目标的计算分析,对缩比理论和计算方法同时做了验证。并指出缩比模型的LRCS计算和测量误差,推算到全尺寸保持不变。研究了海天背景下的目标和背景的各种辐射及散射特性、大气传输特性,设计完成了海天背景下的红外仿真系统。集太阳、天背景辐射计算,大气路径透过率计算,目标和海面建模、辐射及对背景辐射的散射计算等功能于一体。输出结果包括仿真图像,数据、曲线等。更多还原

【Abstract】 The dissertation is supported by a number of National Defense Advanced Research Foundation, The main work and the results of this paper are as follows.Base on analyzing of the basic theory of artificial neural network, a method is presented for building Bidirectional Reflectance Distribution Function(BRDF) model with BP neural network.2D and 3D BRDF models for various materials on laser band and a BRDF model with wavelength parameter for a certain material are built. It turn s out the neural network modeling has the advantages of high accuracy, wide application, and etc.In view of the targets coated by multi-material, the models containing material information are made and a new visualizing-calculation method is presented. A software package for calculation optical characteristic of the targets coated by multi-material is designed and completed. The Laser Radar Cross-Section (LRCS) distribution curves of a large number of targets in the air and on the ground are obtained, with the results analyzed and discussed.The back LRCS distribution curve with the angle of a target drone with serious paint stripping is measured. The LRCS of the target is obtained with the paint stripping of the surface simulated with Monte Carlo method to estimate the seriousness of the paint stripping.A study of the scaling relationship of complex target is made based on scaling theory and measurement. The scaling theory and calculation method are proved by analyzing of results of scaling model measurement and full size model calculated of air targets, such as F16.It is emphasized that the error (absolute values) between calculation and measurement of scale model remains unchanged in the full size model.The radiation and scatter characterizes of the target and sea-sky background and atmospheric transportation characterizes are analyzed. An infrared image simulation system of sea-sky background is designed and completed. A lot can be done with the system, such as the calculating of solar radiation,sky-sea background radiation,and transmissivity of atmospheric, the modeling of target and sea surface,and the scattering of background radiation from target and sea surface.The output form includes infrared simulation image, data file, and curves.更多还原