雷达目标RCS测试系统及微波成像诊断技术研究

【作者】 胡楚锋；

【导师】 张麟兮；

【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】 本文研究室内RCS测试系统和一维、二维、三维微波成像诊断技术。 无论是研究物体的电磁散射特性还是研制具有突防能力的隐身武器系统，RCS测试具有非常重要的意义。通过RCS测试可以验证电磁散射计算的理论和算法，更重要的是，对复杂目标，电磁散射理论计算已非常困难，而通过测试可以直观的获得目标的电磁散射特性数据从而避开复杂的电磁仿真计算。利用微波成像诊断技术可以细致的认识和研究物体电磁散射的分布，有力地促进目标RCS缩减的研究工作。通过对复杂目标的微波成像诊断，得到目标上散射点的空间位置和强度，从而有效的指导武器系统隐身性能的改进。 本文的主要工作分为三大部分： 第一部分首先列举了室内RCS测试系统的基本构成，然后叙述了点频连续波RCS测试系统的工作原理，在此基础上构建了测试系统，并给出了一些定标体及复杂模型的测试结果，最后针对测试存在的误差，分析了影响测量的误差源，并提出了解决方法。 第二部分着重介绍了一种宽带RCS测试系统，即频率步进RCS测试系统。采用高性能的矢量网络分析仪所提供的频率步进信号，通过快速傅立叶变换、软件对消、选取合适的距离波门、时域峰值合成等技术手段，实现了低散射目标的测试。通过比较两种测试系统实测得到的数据，说明了频率步进RCS测试系统具有测试精度高、信息量大、定位准确等优点。 第三部分主要介绍了一维、二维及三维的微波成像诊断技术。首先简要描述了一维成像诊断技术的原理，然后建立了基于转台成像的数学模型，研究了三种不同的算法，通过比较它们各自的特点，找出了一种适合于进行二维成像诊断的有效算法，并将其应用于对复杂飞机模型的诊断性分析，效果良好。最后采用了俯仰角微小差异的两副天线，分别获取两幅相位相干的二维图像，通过对应散射中心的相位变化得到目标的高度信息，从而进行三维成像诊断，并获得了几种散射目标的成像结果。 论文中的所有成果已应用于西北工业大学无人机特种技术国防科技重点实验室。更多还原

【Abstract】 This paper presents indoor radar cross-section(RCS) measurement system and 1-D、 2-D、 3-D microwave imaging diagnosis techniques.RCS measurement is necessary to research the electromagnetic scattering properties of radar target as well as to design stealth weapon system. The theory and algorithm of electromagnetic scattering computation can be verified by RCS measurement, moreover, it’s difficult to compute electromagnetic scattering of complex objects, but the data can be obtained visually by RCS measurement. Microwave imaging diagnosis technique is useful for identifying and analyzing distribution of target, which can improve the studies of electromagnetic scattering theory. The spatial location and magnitude of scattering centers on complex object can be acquired by microwave imaging, so it effectively helps to enhance the performance of stealth weapon system.This paper mainly consists of three parts:In part one, some essential equipments of RCS measurement system in anechoic chamber are listed, then the operating principle of CW system is described. On the basis of these, some test results of standard and complex objects are given. Finally, for the error of measurement, some potential reasons are analyzed, and the corresponding settlements are presented.In part two, a broad band RCS measurement system, called stepped frequency CW system, is demonstrated. The system transmits stepped frequency signal which is provided by high performance PNA., it can realize the measurement of small RCS target by using fast Fourier transform、software counteraction、range gating、synthetic time-domain peaks. By comparing the test results of two systems, it shows that the precision of stepped frequency CW system is higher, and more information can be obtained.In part three, 1-D、2-D、3-D microwave imaging diagnosis techniques are introduced. At first, it describes the theory of 1-D microwave imaging diagnosis techniques. Basis on 2-D imaging modeling of rotating object, three different algorithms are presented, a effective algorithm of diagnosis has been found by comparing the characteristic of them, and then diagnostic results of complex targets are given. Finally, 3-D microwave imaging diagnosis techniques is presented. The vertical position of scattering centers are given by comparing their phase difference of two phase coherent 2-D images which are obtained by using two antennas with a little change in pitch angle. The measured results are given.All of the systems and techniques have been used in the UAV Special Technique National Defense Technology Key Lab of the Northwest Polytechnic University.更多还原