高精度调频连续波激光雷达非线性校正及测距实验研究

发布时间：2018-06-02 22:29

本文选题：激光雷达 + 调频非线性　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：激光雷达在近些年得到了广泛的研究，其中调频连续波（FMCW）激光雷达在高精度测距方面的研究尤为深入。这一体制的激光雷达综合了一系列测距系统特点，具有测距精度高、测距速度快以及适应各种复杂环境等优点。本文所研究的内容是基于FMCW激光雷达体制的基本原理，设计了一套满足近距离内高精度测距的激光雷达系统，并对其中调频非线性校正等关键技术进行了研究，最终通过实验验证了系统测距的可行性。首先，介绍了FMCW激光雷达的基本原理，给出了距离与拍频信号频率的关系，并根据已有的基本理论对系统的关键器件进行了选择。其次说明了激光器调频非线性对测距带来的影响，给出了实验结果来说明。为消除这一影响，引入了同步采样法来校正调频非线性，给出了其理论模型，通过实验验证了此方案的校正效果。对非线性进行校正时，需要得到校正路臂长差的精确值，为此本文采用HCN气室标定校正路臂长差的方案。给出了利用HCN气室标定臂长差的光路设计，并通过实验给出了一个高精度的标定结果。最后，，设计并搭建了本文最终所采用的实验系统。在已搭建的系统基础上进行了测距实验，对光纤长度以及外部空间近距离处一量块的距离进行了测量，分别给出了测距结果，并通过重复实验验证了结果的准确性，给出了存在的误差。
[Abstract]:Lidar has been widely studied in recent years, especially FMCW (Frequency modulated CW) lidar. The lidar system has the advantages of high ranging accuracy, high ranging speed and adaptability to various complex environments. Based on the basic principle of FMCW lidar system, this paper designs a set of laser radar system which can satisfy the high precision ranging in short distance, and studies the key techniques such as the nonlinear correction of frequency modulation, and so on. Finally, the feasibility of the system is verified by experiments. Firstly, the basic principle of FMCW lidar is introduced, the relationship between range and beat frequency is given, and the key devices of the system are selected according to the existing basic theory. Secondly, the influence of laser frequency modulation nonlinearity on ranging is explained, and the experimental results are given. In order to eliminate this effect, the synchronous sampling method is introduced to correct the nonlinear frequency modulation, and its theoretical model is given. In order to correct the nonlinearity, it is necessary to obtain the accurate value of the correction arm length difference. In this paper, the HCN gas chamber is used to calibrate the path arm length difference. The optical design of arm length difference calibration using HCN gas chamber is presented, and a high precision calibration result is given through experiments. Finally, the experimental system used in this paper is designed and built. Based on the established system, the distance measurement experiments are carried out, the length of optical fiber and the distance of a measuring block in the outer space are measured. The ranging results are given respectively, and the accuracy of the results is verified by repeated experiments. The existing errors are given.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN958.98

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