激光测距中回波光子分布特性研究

发布时间：2018-05-20 13:56

本文选题：激光测距 + 回波光子　；参考：《中国科学院大学(中国科学院云南天文台)》2017年硕士论文

【摘要】：卫星激光测距技术是通过精确测定激光脉冲在地面测站和卫星间往返时间间隔来测量卫星到测站的距离。随着科学技术的日新月异,该技术正朝着远距离(月球等深空激光测距)和大范围(非合作目标测距)等方向发展。对于非合作目标和深空目标测距,回波信号极其微弱,于是研究回波光子返回至接收系统的分布特性对有效探测信号具有重要意义。为此,论文完成了如下研究:首先,本论文在激光测距原理的基础上,综合考虑了影响激光测距的各项因素,如大气湍流、光束的指向偏差、目标距离等,从理论上重新推导了测距方程。同时,基于所得方程,利用matlab软件编制了激光测距系统回波光子分布特性研究软件,通过设置测距系统中激光器、发射望远镜、接收望远镜以及探测器等相关参数便可估算回波光子数并可同时显示相应关系曲线。其次,对大气湍流影响测距回波光子数作了更具体、深入地研究。基于光在湍流大气中的传输理论,利用与实际湍流更为接近的间歇性湍流的She模型,推导得到了同时适用于Kolmogorov湍流和间歇性湍流情况的光束扩展和漂移的近似解析表达式。基于该表达式,获得了新的测距方程,并对低轨、高轨卫星以及月球的测距回波光子数进行了数值计算,以分析研究大气湍流间歇性对测距回波光子的影响。结果表明,湍流的间歇性越大,测距回波光子数越多;回波光子数在间歇性湍流与无湍流下的比值最高分别约为1/16、1/17、1/18。本文在云南天文台的1.2m激光测距系统的基础上对回波光子分布特性进行了研究。所得结果可为测距系统设计及其性能评估提供了重要参考。
[Abstract]:Satellite laser ranging technology is to measure the distance between the satellite and the station by accurately measuring the time interval between the laser pulse and the satellite between the ground station and the satellite. With the rapid development of science and technology, the technology is developing in the direction of long distance (deep space laser ranging such as the moon) and large range (non-cooperative target ranging). For non-cooperative target and deep space target, the echo signal is very weak, so it is very important to study the distribution of echo photon returning to the receiving system. Firstly, based on the principle of laser ranging, various factors affecting laser ranging are considered, such as atmospheric turbulence, beam pointing deviation, target distance and so on. The ranging equation is rededuced theoretically. At the same time, based on the obtained equations, a software for studying the photonic distribution of echo waves in laser ranging system is developed by using matlab software. By setting the laser in the ranging system, a telescope is emitted. The number of echo photons can be estimated and the corresponding curves can be displayed at the same time by receiving the relevant parameters such as telescopes and detectors. Secondly, the echo photon number of atmospheric turbulence is studied more concretely and deeply. Based on the theory of light propagation in turbulent atmosphere, an approximate analytical expression of beam propagation and drift for both Kolmogorov turbulence and intermittent turbulence is derived by using the She model of intermittent turbulence, which is closer to the actual turbulence. Based on this expression, a new ranging equation is obtained, and the photon number of ranging echo from low-orbit, high-orbit satellites and the moon is numerically calculated to analyze the effect of atmospheric turbulence intermittently on ranging echo photons. The results show that the larger the intermittency of turbulence, the more the number of photons in ranging echo, and the highest ratio of echo photon number in intermittent turbulence and non-turbulence is about 1 / 16 / 1 / 17 / 1 / 18. Based on the 1.2m laser ranging system of Yunnan Observatory, the characteristics of echo photon distribution are studied in this paper. The results can provide an important reference for the design and performance evaluation of ranging system.
【学位授予单位】：中国科学院大学(中国科学院云南天文台)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.5

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