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第6卷 第3期 信 息 与 电 子 工 程 Vo1．6，No．3 2008年6月 INFORMATION AND ELECTRONIC ENGINEERING Jun．，2008 文章编号：1672-2892(2008)03-0167-05线性调频连续波合成孔径雷达成像算法杨 蒿，蔡竟业(电子科技大学 通信与信息工程学院140教研室，四川 成都 610054)摘 要：线性调频连续波(LFMCW)合成孔径雷达(SAR)因体积小，重量轻，成本相对低，成为近来研究的热点。
连续波SAR 的回波信号通常经过相干解调处理。
针对其独特的应用背景和信号模型，对现有的各种成像处理算法进行了讨论和比较，总结出其优缺点及应用范围。
并对LFMCW- SAR今后的发展提出了展望。
关键词：线性调频连续波；合成孔径雷达；成像算法中图分类号：TN958 文献标识码：ALinear Frequency Modulated Continuous Wave-Synthetic ApertureRadar Imaging AlgorithmYANG Hao，CAI Jing-ye(School of Communication and Information Engineering，UESTC，Chengdu Sichuan 610054，China )Abstract：Linear Frequency Modulated Continuous Wave(LFMCW)-Synthetic Aperture Radar(SAR)has become a focus in recent researches，due to its compactness and low cost. This paper analyses andcompares various imaging algorithms，based on the special application background and signal modelderived from its dechirped raw data. Then the advantages，disadvtanges and application fields of thealgorithms are presented. Future development of LFMCW SAR is prospected.Key words：Linear Frequency Modulated Continuous Wave；Synthetic Aperture Radar；imagingalgorithm目前机载对地观测受到越来越广泛的关注，其应用领域不仅涵盖搜索救援、区域监测、灾害监视与控制等民用方面，还包括小型无人机对地侦察等军事领域。
摘要作为一种激光测距方法，调频连续波激光测距是通过频率线性调制的发射信号与回波信号形成的稳定的拍频信号，再对拍频信号通过快速傅里叶变换来提取出待测目标距离信息的。
较其他激光测距方法相比，该方法具有较高的测距精度和分辨率、测距范围大、且可实现无合作目标的非接触测量等特点，故在10~100米大尺寸测量范围内受到广泛的应用。
目前关于如何提高该测距系统的测距精度和分辨率是激光测距领域重要的研究方向之一。
本文主要工作如下：1.深入对等光频间隔重采样算法的研究，提出了一种新的等间隔重采样方法，即同时取出拍频信号峰谷值位置的点和零点位置的点，并在以上位置处进行重采样，可以将辅助信号的采样频率较之前的采样方法相比提升一倍。
本方法增加了一倍的系统测距量程，同时也可以在待测距离不变的情况下，减小因辅助光纤长度过长带来的光纤色散。
2.提出了一种基于等光频间隔重采样的相位差频率估计算法。
这种方法相当于对傅里叶频谱进行了进一步的细化，可以对傅里叶频谱中两个点之间的信息进行进一步的获取，提高了测距的精度，并从算法仿真和实验的角度进行了验证。
3.对双光路干涉系统光路进行了原理分析和研究，并提出了一种新的思路，即在原双光路干涉系统的基础上引入一个分光镜和一个1/4波片构成一个新的光路，在待测目标位置不变的情况下增加了其一倍的光程，并推导证实改进后的光路能够将测距分辨率提高一倍。
4.掌握了双光路干涉系统、信号处理系统以及二维转台操作系统后，实现三维球坐标测量。
关键词：调频连续波，三维球坐标，相位差频率估计测频法，重采样ABSTRACTAs a laser ranging measurement method, Frequency Modulated Continuous Wave (FMCW) laser ranging is a stable beat frequency signal which is formed by the frequency linear modulated transmitting signal and echo signal, and then the distance information of the target is extracted by the fast Fourier pared with other laser ranging methods, the method has the characteristics of high ranging accuracy and resolution, wide ranging range and it is suitable for non-contact measurement without cooperative targets, so it is widely used in the 10-100 meter large-scale measurement range. At present, how to improve the ranging accuracy and resolution of the ranging system is one of the important research directions in the field of laser ranging.The main works of this paper are as follows:1.The equispaced-phase resampling algorithm was deeply researched and then a new resampling method is proposed.That is, taking out the peak-valley position and the zero position of the beat signal at the same time and then resampling at the above position, the sampling frequency of the auxiliary signal can be doubled compared with the previous sampling method. This method has doubled the range of system ranging and reduces the fiber dispersion caused by the length of auxiliary fiber when the distance to be measured is constant.2.A phase difference frequency estimation algorithm based on equispaced-phase resampling nonlinearity correction is proposed. This method is equivalent to a further refinement of Fourier spectrum, which can further obtain the information between two points in the Fourier spectrum and improve the ranging accuracy. The algorithm simulation and experiment are also carried out to verify the method.3.The principle of dual interferometer FMCW laser ranging system is analyzed and a new idea is proposed. A spectroscope and a 1/4 wave plate are introduced to form a new measurement optical path on the basis of the original dual-path interferometry system, and the optical path is doubled when the position of the target to be measured is unchanged, and the modification is proved by derivation. The new optical path can double the range resolution.4.The three-dimensional spherical coordinate measurement is realized aftermastering the dual interferometer FMCW laser ranging system, signal processing system and two-dimensional turntable operating system.KEY WORDS: FMCW, Three-dimensional spherical coordinates, Phase difference frequency estimation algorithm, Resampling.IV目录第1章绪论 (1)1.1 研究背景与意义 (1)1.2 国内外研究现状 (3)1.2.1 国外研究现状 (3)1.2.2 国内研究现状 (4)1.3 课题来源及主要研究内容 (5)第2章 FMCW激光测距原理及等光频间隔重采样算法 (7)2.1 调频连续波激光测距原理 (7)2.2 FMCW测距精度及分辨率主要影响因素 (8)2.2.1 FMCW测距精度的主要影响因素 (8)2.2.2 FMCW测距分辨率的主要影响因素 (10)2.3 重采样算法原理 (11)2.4 调频连续波激光测距信号处理系统 (18)2.5 本章小结 (18)第3章调频连续波激光测距新算法和光路研究 (21)3.1 基于辅助信号的新重采样方法原理 (21)3.2 新采样算法仿真验证分析 (22)3.3 基于等光频间隔重采样相位差频率估计算法原理 (25)3.4 算法测距仿真分析 (27)3.5 算法实验验证分析 (30)3.6 双光路干涉测距系统研究 (32)3.7 本章小结 (35)第4章调频连续波激光测距误差分析 (37)4.1 激光器光源 (37)4.2 数据采集系统 (41)4.3 测量距离 (45)4.4 本章小结 (46)第5章基于调频连续波激光测距的球坐标测量 (49)5.1 高精密二维转台概述 (49)5.1.1 二维转台系统简介 (49)5.1.2 二维转台主要技术指标以及操作流程 (51)5.2 基于调频连续波激光雷达三维球坐标测量 (53)5.3 本章小结 (58)第6章总结与展望 (59)6.1 全文总结 (59)6.2 论文创新点 (60)6.3 工作展望 (61)参考文献 (63)发表论文和参加科研情况说明 (67)致谢 (69)第1章绪论第1章绪论1.1 研究背景与意义目前随着现代化工业不断创新，高新科技层出不穷，社会对于大尺寸测量的需求与日俱增且趋多元化。
