基于高度扫描的大转角目标ISAR三维成像算法研究-《数据采集与处理.docVIP

基于斜侧视圆周扫描的近场微波成像算法 闫伟1，杜卫民1，许家栋1，李南京2 (1、西北工业大学电子信息学院，西安710129； 2、西北工业大学无人机特种技术国家级重点实验室，西安 710072) 摘 要：针对传统小角度转台成像对大转角目标不能很好聚焦这一问题，研究了基于斜侧视圆周扫描的近场转台成像系统，提出了一种近场大转角成像算法，采用角度域卷积运算，可以快速得到目标的散射点分布，并能够进行很好的聚焦。本文根据点扩散函数给出了圆周扫描成像系统的分辨率计算公式，并推导了频率域和角度域的采样间隔。最后通过仿真和实验结果对该算法进行验证，结果表明该算法具有近场成像的能力，且能够得到高质量高分辨率的目标像。 关键词：逆合成孔径雷达成像；大转角目标；近场成像；斜侧视 中图分类号：TN957 文献标识码：A A Near-field Microwave Imaging Method Based on Side-looking circular Scanning YAN Wei1, DU Weimin1, XU Jiadong1, LI Nanjing2 (1 School of Electronic and Information, Northwestern Polytechnic University, Xian, Shaanxi 710129, China; 2 National Key Laboratory of UAV Specialty Technique, Northwestern Polytechnical University, Xian, Shaanxi 710065, China) Abstract: In this paper, near-field microwave imaging system based on side-looking circular scanning is studied. It can solve the problem that the traditional turntable imaging system can not focus the targets with large angular rotation very well. The proposed system introduces not only the sparse sampling technique in frequency domain, but also the fast convolution algorithm in angular domain. The advantage of the proposed method is that it can obtain the high resolution image quickly. The resolution of the proposed method is deduced according to point spreading function. The sampling criterion is then presented in both frequency domain and angular domain. The proposed method is testified by both simulation results and experimental results. The results show that the proposed method can be used to acquire high quality and high resolution image. Key words: inverse synthetic aperture radar imaging; large angle rotation; near-field imaging; side-looking 引 言 目标的电磁散射特性表征了雷达目标的固有特征，可以用于对目标进行分类、辨认与识别。通常获得目标散射特性的方法有两种：仿真计算和实测。随着计算机技术的发展，以计算机图形学和电磁场数值分析为基础的电磁特性仿真计算能力有了极大的提高。但是对于电大尺寸目标，其散射特性的数值分析仍然存在着许多问题。例如高频方法的理论模型粗糙、数值误差较大、射线自动寻迹太复杂，而数值方法的计算量过大、计算资源的需求太高[1-2]。实测结果的优点是可信程度高，然而通常需要满足远场条件，导致测试场地的占地面积很大，测试费用昂贵，很难得到完备的散射特性数据。如果能通过近场测试获得目标的散射特性，将会大大减少测试费