| 月球激光测距的新技术方法研究 |
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| 引用本文： | 熊耀恒.月球激光测距的新技术方法研究[J].天文研究与技术,2002(1). |
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| 作者姓名： | 熊耀恒 |
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| 作者单位： | 中国科学院云南天文台 云南昆明650011 |
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| 摘 要： | 月球激光测距是国内外所瞩目的宏伟目标 ,代表着单光子探测技术的高峰。本论文的目的是探索提高激光测月回波光子数的新方法 ,进而增加激光测月成功的几率。其思路是源于一个新的想法 :在激光测月过程中引入大气波前倾斜量实时补偿的技术。首先介绍激光测月的现状和其难度所在 :回波光子数太少 ,基本上属于亚光子探测范畴。在现有技术条件下 ,本文对影响激光测月回波光子数的因素逐一进行分析讨论 ,提出应该把激光束截面能量分布和大气湍流效应包括进去。为此分析讨论了大气湍流和大气中光场的基本统计性质、激光束在大气中传输时所受大气湍流的影响以及大气湍流对激光测距的影响 ,得出大气湍流特别对激光测月有着明显影响的结论。在此基础上对传统的激光测距方程进行了修正 ,使其应用到激光测月时更符合真实的情况 ,从而指导补偿的进行。涉及到在激光测月中对受大气湍流而畸变的激光束进行补偿 ,本文抓住重点 ,通过分析看出对大气倾斜量的实时补偿是提高激光测月回波光子数的重要因素。结合激光测月以及云南天文台现有测距系统的实际情况 ,本文独创性地提出利用激光测月目标近旁一定大小区域的扩展面源探测与计算大气倾斜量 ,然后对激光测月中的激光束进行大气倾斜量实时补偿的新技术方法。在分析比较
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| 关 键 词： | 月球激光测距 回波光子数 大气湍流 波前倾斜探测 实时补偿 |
Research on a New Technical Method for the Lunar Laser Ranging |
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| XIONG Yao-heng,Ph.D.Research on a New Technical Method for the Lunar Laser Ranging[J].Astronomical Research & Technology,2002(1). |
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| Authors: | XIONG Yao-heng PhD |
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| Abstract: | Lunar Laser Ranging (LLR) is a great goal in the world and it represents the height of the single photon detection. The goal of this thesis is to study a new technical method for increasing returned photon numbers for the lunar laser ranging, and to try to increase the successful probability of the lunar laser ranging. The idea originates a new concept that is to introduce the real-time compensation technique of atmospheric tip-tilt on the LLR First, the status of the lunar laser ranging and its difficulties are introduced in the thesis. The difficulty of the LLR is that the returned photon numbers are too few. The LLR basically belongs to sub-single photon detection. All factors that affect the returned photon numbers of the LLR are analyzed and discussed at current technique condition, and therefore it is proposed to consider the atmospheric turbulence effects and the energy distribution of the laser beam on the LLR. For this new idea, the basic statistic properties of the atmospheric turbulence and the electric field in the atmosphere, the effects of atmospheric turbulence on the laser beam propagation and on the laser ranging are analyzed.It is concluded that the atmospheric turbulence has the significant influence on the laser beam propagation, especially on the LLR. Following above analysis, the classical laser ranging equation is modified so that it can be more near the true condition when it applies to the LLR and can guide the compensation that we want to do. For the distorted laser beam compensation on the LLR due to the atmospheric turbulence,It is found that the real-time compensation of the wavefront tilt is an important factor for increasing the returned photon numbers of the LLR. After combining the LLR and the laser ranging system of Yunnan Observatory,a new technical method is proposed.A small area near the reflector array on the moon surface is used as an extended source to detect and calculate the wavefront tilt, and then carry on the real-time tilt compensation for the laser beam on the LLR. After analysis of several algorithms for calculation of the wavefront tilt from a low contrast extended source, the absolute difference algorithm is the best one. The details of the technical plan to the new method for the LLR,its theory and technique are also discussed. |
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| Keywords: | Lunar laser ranging returned photon numbers atmospheric turbulence wavefront tilt sensing real-time compensation |
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