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SAR雷达成像仿真

摘 要

雷达发展初期由于分辨率较低，其作用主要是“点”目标的检测和跟踪。而现代机载雷达系统则要执行更多任务，从目标检测和识别到大面积地形测绘。地形测绘可通过合成孔径雷达（SAR）实现。通过采用相干辐射照射地面并测量回波信号，SAR可以产生地表的高分辨率二维图像，其成像质量由系统分辨单元的大小决定。分辨单元由系统的距离和方位分辨率共同决定。高的距离分辨率通过脉冲压缩技术实现。高方位分辨率取决于天线尺寸及雷达波长，可以通过雷达运动达到增加天线孔径从而提高方位分辨率的目的。

本文简介了SAR的发展历史，着重研究条带式状正侧视SAR的成像原理，建立点目标回波模型，重点讨论了其R-D成像算法，介绍了目前常用的其他成像算法，在频域内对该算法进行了距离徙动校正（RCMC），从而得到多点目标的Matlab仿真。

关键词：SAR 正侧视 距离徙动校正 成像

ABSTRACT

Because of low resolution radar at the early stage of development, its main function is \perform more tasks, from the target detection and recognition to terrain mapping in large area. Topographic mapping can be actualized by synthetic aperture radar (SAR) . By using the coherent radiation and measure the echo signal,SAR can produce high resolution two-dimensional image , its imaging quality depends on the system resolution cell size. Resolution unit consists of range and azimuth resolution .High range resolution is achieved through the pulse compression technique. High range resolution depends on the size of the antenna and radar wavelength,the carrier’s motion is used to increase the antenna aperture radar so as to improve the range resolution of the.

This paper introduces the development history of SAR, focuses on the imaging principle of belt shaped side looking SAR, and establishes the echo model of point target. The paper mainly part focuses on the R-D imaging algorithm, and introduces some other common imaging algorithm.The algorithm of range migration correction(RCMC)

is

solved

in

frequency

domain,thereby

getting

the

several-point-target Matlab imaging simulation.

Keyword: SAR Side looking Range migration correction Imaging

I

目 录

第一章 绪论 .................................................................................................................... 1

1.1 合成孔径雷达（SAR）的发展历程和现状 ................................................... 1 1.2 现代SAR的发展方向及意义 ......................................................................... 2

1.2.1 多参数SAR系统 ................................................................................ 2 1.2.2 聚束SAR .............................................................................................. 2 1.2.3 极化干涉SAR（POLINSAR） .......................................................... 3 1.2.4 合成孔径激光雷达（Synthetic Aperture Ladar） ............................. 3 1.2.5 星载合成孔径雷达的小型化 ................................................................. 3 1.2.6雷达与可见光卫星的多星组网是主要的使用模式 ............................ 4 1.3 论文的内容及结构安排 ................................................................................... 4 第二章 合成孔径雷达的工作原理 ................................................................................ 5

2.1 线性调频信号及其脉冲压缩 ........................................................................... 5 2.2 方位分辨率 ....................................................................................................... 6 2.3 SAR点目标回波模型 ....................................................................................... 8 第三章 合成孔径雷达的成像算法 .............................................................................. 10

3.1 运动补偿技术的发展及现状 ......................................................................... 10

3.1.1 引言 ...................................................................................................... 10 3.1.2 基于运动传感器补偿算法的发展 ...................................................... 10 3.1.3 运动补偿算法的发展 .......................................................................... 11 3.1.4 基于回拨数据运动补偿算法的发展 .................................................. 12 3.1 距离徙动 ......................................................................................................... 12 3.2 距离-多普勒算法（R-D算法） .................................................................... 15

3.2.1 原始正侧视及其改进的距离多普勒算法 .......................................... 15 3.2.2 斜侧视下距离多普勒算法 .................................................................. 17 3.3 其他SAR成像算法简介 ............................................................................... 18

3.3.1 线性调空变平移算法（Chirp Scaling，C-S） ................................. 18