基于NURBS曲面复杂模型的RCS计算

【作者】 刘伟；

【导师】 侯新宇；

【作者基本信息】 西北工业大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 雷达散射截面(RCS)是描述雷达目标特性的主要参数，如何精确计算复杂目标的雷达散射截面一直是电磁场理论研究的一个重要课题，并且雷达截面的计算对于飞行器隐身性能的研制有着导向作用，因此研究开发针对复杂模型的RCS计算软件具有较高的科研和实际应用价值。 本文围绕雷达散射截面的基本概念，依据开发RCS工程计算软件的需求，分析了如何利用物理光学法计算基于非均匀有理B样条(NURBS)曲面模型的RCS，通过驻相法计算模型表面感应电流的散射场，分别详细讨论了软件在计算复杂曲面模型RCS时的模型来源问题、模型前置处理和消隐问题。本文主要研究内容为： 首先，通过对当前几种流行的国际数据标准的分析，为RCS工程计算软件添加了基于“基本图形转换规范”(IGES)的数据接口，实现了计算软件和CAD建模软件间的交互。 其次，对模型进行了前置处理，包括利用反算法去除节点和通过Chebyshev多项式逼近对高次曲面降次，特别在节点去除中提出了一种新的数据点选取方法，使NURBS转换为Bezier的数量减少了，提高了RCS散射计算的效率和精度。 最后，对复杂模型进行了消隐处理，这是本文所研究的关键问题。分别论述了Catmull曲面分割法和Weley-Altherton曲面裁剪法，并将Catmull曲面分割法加以实现，其中特别针对Z-Buffer自身瓶颈提出了一种射线法较好地加以缓解。 本文还对RCS计算软件的消隐模块和软件整体计算性能进行了实例测试，并将测试结果和测量结果或其它方法的计算结果进行了比较。更多还原

【Abstract】 The Radar Cross Section is a very important parameter of the radar target and how to exactly compute the Radar Cross Section always is an electromagnetics researchful important problem which directs design of the aerocraft shelter, therefore researching on developing the software of computing the complex models RCS has the quite high research and practicality value.Based on the concept of RCS and requirement of RCS software, this dissertation analyzes how to compute RCS of Non-Uniform Rational B-Spline surface models by Physical Optics and the scatter of model obverse inducting current by Stationary Phase Method, respectively detailedly discusses model source、 primarily treated with and shadow complex model of compute software. The main researchful content of this dissertation:Firstly, based on analysis of some fashion international data standard, the data-exchange interface on Initial Graphics Exchange Specification (IGES) for the computing RCS software is realized, achieving the data exchange between the CAD model building system and the computing software.Secondly, primarily treating with computing model has been done that included wiping off knots by anti-count and reducing high degree surface rank by Chebyshev multinomial approach this expressly achieves a new choosing data point means that reducing amount of the NURBS changed into Bezier and improving precision and efficiency of computing RCS.Finally, realizing the surface shadow has been done that is the dissertation reasearchful pivotal problem which respectively analyzes "Catmull Surface Division" method and "Weley-Altherton Trimmed Surface" method, expressly achieves "Catmull Surface Division" method that solves Z-Buffer computing bottle-neck by a radial method.This dissertation also respectively tested the shadowing module and the whole computational RCS software and the results compares with measure and other method results.更多还原