便携式光学湍流综合测量装置的探索性研究

One needs to estimate the optical effects of atmospheric turbulence in real time in some practical engineering application, such as astronomical observation, imaging through turbulence, wireless optical communication, and laser propagation through turbulence. Atmospheric coherence length and isoplanatic angle are two important parameters which describe optical effects of turbulence. Measuring atmospheric coherence length and isoplanatic angle in real time is of great significance in understanding the evolution characteristics of atmospheric turbulence and practical application. But at present, the measuring device for atmospheric coherence length and isoplanatic angle is large in size and inconvenient to carry, which cannot meet the increasing demand of the optical turbulence parameters in the practical application. This project intends to study a portable integrated measuring device for optical turbulence which can measure atmospheric coherence length and isoplanatic angle simultaneously. Through theoretical analysis and numerical calculation, this project investigates the influence of the structure of the sub-aperture in differential image motion monitor (DIMM) on the measurement and the corresponding correction approaches, and explores the method of measuring the isoplanatic angle in finite distance using a small telescope. On the basis of this, a portable integrated optical turbulence measurement device will be developed, then the atmospheric propagation experiment will be designed to verify the reliability of this device. The study will provide a great convenience for real-time monitoring the status of atmospheric optical turbulence, and will also provide the parameters basis for the engineering application of laser propagation through atmosphere and adaptive optics

天文观测、湍流成像、无线光通信、激光大气传输等实际工程应用中需要实时评估大气光学湍流效应的影响。大气相干长度和等晕角是描述光波大气传输湍流效应的两个重要参数，实时测量大气相干长度和等晕角对了解大气湍流演变特征及实际工程应用具有重要意义。但目前大气相干长度和等晕角测量装置体型较大、携带不便，满足不了实际应用对光学湍流参数日益增长的需求。本项目拟探索性研究可同时测量大气相干长度和等晕角的便携式光学湍流综合测量装置，通过理论分析和数值计算研究差分像运动测量仪（DIMM）子孔结构对大气相干长度测量的影响以及相应的修正方法，探索研究利用小口径望远镜测量有限距离等晕角的测量方法；在此基础上研制便携式光学湍流综合测量装置，并设计开展大气传输实验验证该装置的可靠性。该研究将为实时监测大气光学湍流状态提供极大便利，为激光大气传输、自适应光学等工程应用提供参数依据。

大气相干长度和等晕角是描述光波大气传输湍流效应的两个重要参数，实时测量它们对了解大气湍流演变特征及实际工程应用具有重要意义。但目前测量装置体型较大、携带不便，满足不了实际应用对光学湍流参数日益增长的需求。本项目探索性研究可同时测量大气相干长度和等晕角的便携式光学湍流综合测量装置。. 本项目获得的重要结果有：传统DIMM对接收光孔的几何结构限制可以大大放宽，对于整层观测来说，设置两个子孔紧挨着，此时接收主体望远镜的口径可以缩小到12cm左右，这个口径正好可以用来观测恒星闪烁测量等晕角，从而实现对大气相干长度和等晕角的便携式测量。. 本项目的关键数据及科学意义有：经过理论分析与实验验证，发现DIMM中子瞳间距的问题实际上是倾斜非等晕性问题，即使子孔的几何结构不满足上传统要求，依然可以利用新的计算公式来测量大气相干长度。