室内大气湍流模拟系统的研究

发布时间：2018-12-11 06:40

【摘要】：在地球表面使用望远镜观测天体时,由于大气湍流的存在致使光波传输介质发生随机扰动,导致天文望远镜观测到的天体图片模糊不清。自适应光学技术的出现,极大的改善了地基望远镜成像不清的缺点。而对大气湍流进行模拟是发展自适应光学技术不可缺少的一部分,因此对大气湍流进行模拟具有重要的理论和实践意义。数值模拟大气湍流对室内测试自适应光学系统具有可控性、重复性、成本低等诸多优点。本文对现阶段人们使用较多的Zernike多项式法和功率谱反演法进行了详细分析。在此基础上,提出采用非均匀采样方法下功率谱反演法来模拟大气湍流相位屏。本文中采用Kolmogorov功率谱进行数值模拟,得到了在低、高频与理论值都很吻合的结果,充分证明了非均匀采样下功率谱反演大气湍流算法的有效性。使用非均匀采样下功率谱反演大气湍流算法得到的相位屏虽具有很高的质量,但因非均匀采样方法下不能使用快速傅里叶变换导致相位屏生成速度极慢。针对这一问题,本文提出使用GPU技术和NUFFT算法来加速湍流相位屏的模拟。模拟结果证明GPU技术和NUFFT算法对湍流相位屏模拟具有很高的加速效果,为湍流相位屏的数值模拟节省了大量时间。在湍流相位屏数据生成之后,还需要解决如何搭建光波传输链路实现对光束的调制,为解决这一问题本文采用纯相位液晶空间光调制器(LC_SLM)作为湍流模拟器件。将湍流相位屏作为控制信号加载到液晶空间光调制器中,实现了大气传输链路的建立,为自适应光学系统进行室内测试提供条件。本文在此基础上将湍流相位屏的生成模块与信号加载模块集成在一起,并添加显示模块,实现了大气湍流数值模拟控制平台的开发。并对模拟算法和控制界面做了大量优化和美工,使控制平台具有高效稳定的工作性能。
[Abstract]:When the telescope is used to observe celestial bodies on the surface of the earth, the atmospheric turbulence causes random disturbances in the light wave transmission medium, which results in the blurred images of the celestial bodies observed by the astronomical telescope. The emergence of adaptive optics has greatly improved the shortcomings of ground-based telescope imaging. The simulation of atmospheric turbulence is an indispensable part of the development of adaptive optics, so the simulation of atmospheric turbulence has important theoretical and practical significance. Numerical simulation of atmospheric turbulence has many advantages, such as controllability, repeatability, low cost and so on. In this paper, Zernike polynomial method and power spectrum inversion method are used in detail. Based on this, a power spectrum inversion method is proposed to simulate the atmospheric turbulence phase screen. In this paper, the Kolmogorov power spectrum is used for numerical simulation, and the results are in good agreement with the theoretical values at low and high frequency, which fully proves the validity of the power spectrum inversion algorithm for atmospheric turbulence under non-uniform sampling. Although the phase screen obtained by the power spectrum inversion algorithm for atmospheric turbulence under non-uniform sampling has high quality, the fast Fourier transform (FFT) can not be used in the non-uniform sampling method, which results in the extremely slow generation speed of the phase screen. To solve this problem, GPU technique and NUFFT algorithm are proposed to accelerate the simulation of turbulent phase screen. The simulation results show that the GPU technique and the NUFFT algorithm have a high acceleration effect on the turbulent phase screen simulation and save a lot of time for the numerical simulation of the turbulent phase screen. After the generation of turbulent phase screen data, it is also necessary to solve the problem of how to construct a light wave transmission link to realize the modulation of the beam. In order to solve this problem, a pure phase liquid crystal spatial light modulator (LC_SLM) is used as the turbulence simulation device in this paper. The turbulent phase screen is loaded into the liquid crystal spatial light modulator as the control signal, and the atmospheric transmission link is established, which provides the condition for the indoor test of the adaptive optical system. Based on this, the generation module of turbulent phase screen is integrated with the signal loading module, and the display module is added to realize the development of atmospheric turbulence numerical simulation control platform. The simulation algorithm and control interface are optimized and applied to make the control platform work efficiently and stably.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O357.5

【相似文献】