直接探测激光二极管雷达的测距特性研究

【作者】 张鹏；

【导师】 来建成；

【作者基本信息】 南京理工大学 ， 光学工程， 2010， 硕士

【摘要】 激光二极管器件日益成熟,为新型激光测距仪的研制提供了小型化、高重频的廉价的探测光源,给激光雷达领域的研究注入了新的活力。激光二极管相比于传统的调Q激光器,脉冲峰值功率较低,上升沿缓慢,这使得激光二极管雷达的测距特性与传统的固体激光雷达有较大的差异。为此,本论文给出了一种更具有普适性的激光二极管测距特性的评价体系,并在理论和实验上对激光二极管雷达的测距特性进行了研究。在理论上,建立了测距型激光二极管雷达测距过程仿真的随机模型,在MATLAB环境下编制了仿真计算程序,并进行了模型正确性的实验验证。该模型能够考虑鉴别电平和电路带宽等系统参数以目标反射特性、目标距离和大气传输特性等工作条件对激光二极管雷达测距过程的影响。在此基础上,通过仿真测距实验,研究了鉴别电平、系统带宽和目标反射特性等因素对激光二极管雷达测距特性的影响。在实验上,搭建了测距型激光二极管雷达的实验装置,并利用该装置进行了不同条件下的大量定点测距实验。通过实验验证了数值仿真得到的鉴别电平、系统带宽和目标反射特性等因素对激光二极管雷达测距特性影响规律的正确性。研究结果表明：在低信噪比条件下,激光二极管雷达测距数据的离散分布将明显偏离正态分布；同时在保持其它参数不变的情况下,随着鉴别电平的升高和系统带宽的增加,测距密集度参数均表现出了先增加后减小的规律,存在最佳的鉴别电平和系统带宽值。在本文的系统参数下,最佳鉴别电平和为系统带宽值为500mV和25MHz。综上可见,该研究工作和结果对于测距型激光二极管雷达的优化设计和后续三维数据重建及分析有着重要的参考价值。更多还原

【Abstract】 Laser diode devices is becoming more sophisticated. provide a compact, low-cost and high-repetition detection light source for the development of new laser range finder, which pour new energy into the field of laser radar research. Compared to the traditional Q-laser, laser diode has lower pulse peak power, slowler rising time, which makes the characteristics of laser diode radar ranging are quite different from traditional solid laser radar. So,this paper presents a more universal characteristics of the laser diode ranging evaluation system, and studies on laser diode characteristics of radar ranging in theory and experiment.In In theory, we establish simulation of the stochastic model,which depend on a distance-based laser diode radar ranging process. The simulation is developed in the MATLAB environment and verify the correctness of the model from experiment. The model can consider the influence of system parameters such as theshold level and bandwidth, and working conditions such as atmospheric transmission characteristics reflection characteristics of the target, target distance to radar ranging. On this basis, through ranging simulation experiments, we identify the influence of threshold level, the system bandwidth and target reflection characteristics characteristics of laser diode radar range. In the experiment, we build the laser diode radar ranging system, and use of the devices under different conditions of a large number of fixed-point ranging experiments. Experimental results show influence law of the threshold level, the system bandwidth and target reflection properties and so on to characteristics of laser diode radar ranging in the numerical simulation results is correct. The results show that:in the low SNR conditions, the discrete distribution of the laser diode radar ranging data will significantly deviate from the normal distribution; while keeping other parameters unchanged, with increase of threshold level and system bandwidth and keep ranging parameters steadly.the parameters of characteristics of laser diode showed decreases and increases in law, there is an optimal threshold level and system bandwidth. In this paper, the best threshold level and system bandwidth is 500mV and25MHz.In summary, the results of the research shows important reference value for optimum design of ranging laser diodes radar and follow-up three-dimensional reconstruction and analysis of target data.更多还原