近地层自适应光学系统大气湍流补偿方法研究

项目名称： 近地层自适应光学系统大气湍流补偿方法研究

项目编号： No.11203052

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 李邦明

作者单位： 中国科学院国家天文台南京天文光学技术研究所

项目金额： 26万元

中文摘要： 近地层自适应光学（GLAO）是新一代大视场自适应光学技术，可在较大视场内提高望远镜系统的分辨率，从而为科学仪器的天文观测提供更好的条件。本项目针对GLAO系统中波前探测噪声大、延迟误差和变形镜电极饱和影响严重等关键问题，按照现代控制理论，建立控制系统的状态空间模型；根据随机过程理论，结合大气湍流的统计模型,利用卡尔曼预测方法对近地层大气湍流相位进行预测，降低探测噪声和延迟误差的影响；通过线性二次高斯控制中引入罚函数的方法，将有约束的变形镜电极控制信号求解问题转化为无约束优化问题，消除截止误差的影响，最终建立近地层自适应光学系统大气湍流补偿方法的理论体系。该项目研究成果可应用于我国未来极大望远镜的设计和建造，特别是可为我国下一步在南极建造大口径望远镜的自适应光学系统提供理论支持。

中文关键词： 近地层自适应光学；大气湍流；波前重建；波前控制；

英文摘要： Ground layer adaptive optics (GLAO) is a new generation of a adaptive optics technique for wide field imaging, which can improve the resolution of the telescope over a large field, and provide better conditions for astronomical observations through scientific instruments. The measurement noises of the wavefront snsors, the delay errors of the control system and the actuator saturation of the deformable mirror are three key factors, which have serious effects on the control of the GLAO system. The state-space model of the GLAO control system is built according to the modern control theory. On the basis of a stochastic process theory and a statistical model of atmospheric turbulence, the effects of measurement noises and delay errors can be reduced by the prediction of the phase of atmospheric turbulence near the ground by a Kalman filter algorithm. The cut-off error can be eliminated by a Linear Quadratic Gaussian(LQG) controller combined with a penalty function method, through which a constrained problem can be transformed to an unconstrained one. At last, the compensation method for atmospheric turbulence for GLAO system is developed. The research results provide a theoretical foundation for the design of the adaptive optics system of the large-aperture Antarctic telescope in China.

英文关键词： Ground layer adaptive optics；atmospheric turbulence；wavefront reconstruction；wavefront control；