基于伪随机码调制和光子计数的激光测距和三维成像技术
文献类型：学位论文
| 作者 | 杨芳 |
| 学位类别 | 博士 |
| 答辩日期 | 2014 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈卫标 |
| 关键词 | 伪随机码调制，光子计数 ，三维成像，激光测距，星载激光雷达 |
| 其他题名 | Laser Ranging and Three Dimension Imaging Technique Based on High Speed Pseudorandom Modulation and Photon Counting |
| 中文摘要 | 对地空间激光三维成像雷达可获取大范围地面目标的三维信息，在行星地貌测绘和地球科学中都有广阔的应用前景。传统的对地三维成像体制是由低重频、高能窄脉宽激光器，大口径望远镜结合线性探测模式实现。这种成像体制存在目标测量点稀疏，地表分辨率低的问题，不能满足远程高分辨率测绘的需求，因此，未来空间探测的发展趋势必然是新探测体制与新技术的相互结合。 本文进行了高速伪随机码调制和光子计数的激光雷达系统的相关理论、关键技术和系统设计的研究，开展大量系统实验并取得了初步的结果。主要研究内容包括： 总结了传统星载对地激光三维成像体制的技术特点，分析存在的问题，提出未来星载激光三维成像体制的发展趋势。对基于伪随机码调制和光子计数模式下的系统进行原理介绍、信噪比分析，探讨影响信噪比的因素，并讨论了目标和背景光学特性，计算了应用系统的背景光功率。针对星载平台应用，进行系统的性能仿真和参数分析。 根据系统的应用目标，开展了基于伪随机码调制和光子计数的光纤激光雷达的系统设计。提出和研制了一套技术原理验证实验装置，装置主要由FPGA电路驱动高速伪随机码调制商用光通信模块产生种子脉冲光，利用自研的光纤放大器形成激光发射光源，计数率达到100MHz的GHz正弦波门控模式下的InGaAs/InP多模耦合的单光子探测器组成。系统具备1GHz的高调制速率，以及高速率光子计数探测的能力。 利用该装置，开展了系统的验证实验。首先利用光纤延时衰减方法，测试了不同伪随机码调制速率、不同形式伪随机码、不同长度伪随机码的情况下的系统性能。结果表明，在高调制速率、高阶数的M序列伪随机码下，系统可获得高信噪比和测距精度。在激光器重复频率10kHz，伪随机码序列长度2.047μs，输出峰值功率31.9W的情况下，得到系统3.97km的远程测距能力，测距精度为8.2cm。 利用本激光测距体制，增加光机扫描机构，搭建三维扫描成像系统。并开展了近距离成像实验研究，得到100米处清晰的三维成像效果。表明该激光测距体制可应用到高分辨率的激光三维成像系统中，并具有星载应用潜力。 |
| 英文摘要 | Three dimensional imaging lidar has broad application prospects in planetary topography mapping and earth sciences for its wide range measurement in obtaining three-dimensional information of ground targets. Traditional three-dimensional imaging systems are mostly composed of low-frequency high-energy short pulse- width laser, large receiver telescopes and linear detector. However, they are not suitable for long-distance high-precision remote sensing due to sparse target measurement points and low ground resolution. Therefore, the combination of new ranging system and new technology will be the trend of future space exploration.The related theory, key technology and system design of high pseudorandom modulation and photon counting technique have been discussed in the dissertation. A series of system expereiments are carried out and initial results are obtained. Research work mainly includes the following parts. The characteristics of traditional spaceborne three-dimensional imaging technique is summarized and the trend of spaceboren three-dimensional laser imaging system is analysed. The principle of pseudorandom-modulation photon-counting lidar is introduced. The ratio of signal to nosie (SNR) is analysed and influence factors of SNR are discussed. The optical properties of the target and background are discussed and the power of background light based on the system is calculated. For spaceborne platform applications, performance simulations and parametric analysis are performed. According to application requirements, the design of pseudorandom-modulation photon-counting all-fiber lidar system and corresponding experimental setup to verify the technical principles are carried out. The experimental system consists of a commercial optical-fiber-communication module used as a seed, a fiber amplifier and single-photon detector. The seed is modulated by high-speed pseudorandom generated by FPGA contral circuit and then is amplified by the home-made fiber amplifier, thus serving as the laser source. The InGaAs/InP multi-mode coupled single-photon detector operated in GHz sinusoidal-wave gating mode has as high as 100MHz counting rate. The device can realize 1GHz high modulation rate and high speed photon counting detection. Based on the system, a series of verification experiments are conducted.The ranging performance is demonstrated through the optical fiber delay method. Raning performances are tested under different pseudorandom modulation frequencies, different pseudorandom codes and different pseudorandom code lengths. Experimental results show that high SNR and ranging accuracy can be obtained under high modulation frequency, high M-sequence pseudorandom code length. With the laser modulation frequency of 1GHz, the pseudorandom sequence length of 2.047μs and the peak power of 31.9w, 3.97 km maximum ranging capacity and 8.2 cm ranging accuracy are acqired. By adding a scanning mechanism to the ranging device, the three-dimensional scanning imaging system is established. Three-dimensional imaging experiments are carried out and a clear image of about 100m distance is get. Results show that the pseudorandom modulation and photon counting technique can be applied to high ranging resolution three-dimensional imaging system and has the potential for spaceborne application. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15891]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 杨芳. 基于伪随机码调制和光子计数的激光测距和三维成像技术[D]. 中国科学院上海光学精密机械研究所. 2014. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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