摘要
合成孔径雷达(SAR,Synthetic Aperture Radar)技术作为一种新的雷达技术,现已广泛应用于军事和国民经济的许多领域中。SAR由于具有全天时、全天候、高分辨率等特点,得到了各国的广泛重视。
雷达目标回波模拟技术是雷达研究领域必不可少的技术。如果对目标回波全部采用外场测试,将耗费大量的人力、物力、财力,且易受天气状况影响,延长研制周期。利用现代仿真技术、微波成像技术、数字电路技术的雷达目标回波模拟器,以其经济、灵活和可重复性等优点,已成为雷达系统的设计、开发、测试、教学和培训中不可缺少的重要组成部分。
随着SAR应用的日益广泛,SAR回波模拟对于SAR成像算法的验证、SAR图像的判读和几何校正以及SAR图像目标和特征的识别等具有很大的应用价值。SAR回波模拟算法的研究方向也已经由最初的简单点目标模拟,变为多种模式的典型地面目标模拟算法。
本论文的研究内容主要是围绕着SAR回波模拟算法的优化和实现展开。首先介绍SAR的工作原理,SAR回波模拟典型算法；然后针对SAR的2DFFT算法进行优化,优化的方法主要采用图形电磁学方法：利用图形电磁学减少目标后向散射系数计算中的去遮挡部分,大大减少了计算量,从而优化了2DFFT算法,本文应用优化的2DFFT算法对随机地面和典型建筑物进行了仿真,这两种典型目标就构成了对地面的基本场景模拟；其次将2DFFT算法与一种经典的RTPC算法对比,得到了两种算法的优缺点和适用范围；最后运用Labview编写上位机软件,将2DFFT算法仿真的波形下载到硬件平台上,完成了SAR雷达模拟器的研制,得到了2DFFT算法的回波波形。
As a new radar technology, Synthetic Aperture Radar (SAR) technology has evolved to satisfy a variety of application for both civilian and military users. As long with the increasing and extensive application of SAR, many fields such as design of SAR system, evaluating of imaging algorithms, or suppression of noise and clutter ask for more demands and higher quality of SAR raw signal data, the technique of SAR raw signal simulation is being developed under this background.
Radar target radar echo simulation technology is indispensable for technology research. If the target echo used in all field trials, it will spend a lot of manpower, material and financial resources, and it is vulnerable to weather effects and will extend the development cycle. Using modern simulation technology, microwave imaging technology and digital circuit technology.it has become an important part in the radar system design.
With the increasingly widespread application of SAR, SAR echo simulation algorithm has great value for the validation of SAR imaging and characteristics of SAR image target recognition. SAR raw signal simulation algorithm research has changed into a multi-mode simulation algorithm typical ground targets from the initial simulation of a simple point target.
This thesis is focusing on SAR echo simulation algorithm around the optimization and implementation. First introduces the working principle of SAR. SAR raw signal simulation of typical algorithms; and for the SAR's 2DFFT algorithm optimization, optimization methods are mainly graphical electromagnetic methods:the use of graphics to reduce electromagnetic target in the scattering coefficients to block part of the greatly reduces the computation to optimize the 2DFFT algorithm, this algorithm optimized the 2DFFT buildings were typical of the ground and simulated two typical targets on the ground to form the basic scenario simulation; followed by the 2DFFT algorithm with a kind of classical RTPC algorithm compared the two algorithms are the advantages and disadvantages and applicability; the final preparation using Labview software,2DFFT algorithm simulation waveforms downloaded to the hardware platform to complete the development of the SAR radar simulator.
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