摘要
为了更好地对于大口径望远镜中频误差进行评价与分配,本文引入了结构函数来进行研究。本文首先对于结构函数的基本性质进行了推导,并与传统的误差均方根(RMS)进行比较,表明了其表征不同尺度误差的能力。之后分析了系统波前在不同的评价尺度下的统计特性差异,得出在较小尺度下,系统的误差分布可以较好的服从正态分布,而随着尺度的增加(如大于100mm)会逐渐偏离正态分布的结论。然后根据结构函数的基本性质,提出了一种可以同时考虑诸多误差源的大口径望远镜中频误差分配方法。结合美国三十米望远镜(TMT)团队所提出的标准化点源敏感性(normalized Point Source Sensitivity,PSSn),建立起了由结构函数到标准化点源敏感性的换算关系,通过此方法来进行误差分配指标间的交叉验证以及与其他单元技术之间的对接。最后,根据本文所提出的方法,对于某大口径望远镜的主镜系统进行了误差分配,得到在大尺度均方根为25nm,粗糙度为1nm,中频尺度为250mm,大气相干长度为0.4m(检测环境)的要求下,该系统的结构函数满足要求,同时由要求结构函数所计算得到的PSSn=0.999 6大于由镜面数据直接得到的PSSn=0.999 5,同样满足要求。
To better evaluate and distribute the middle frequency errors of large telescope,structure function was put forward for such purposes in this paper.Firstly,we carried out a derivation in basic property of the structure function and compared it with traditional root mean square（RMS）,which indicates its capability of representing different-scale errors;secondly,conducted an analysis on the statistical property difference of system wavefront under different evaluation scales,which indicates that system error distribution can better follow the normalized distribution under small scale and tendto deviate from the normalized distribution with the scale increase（e.g.：a scale greater than 100mm）;then a method for middle frequency error distribution of large telescope that can simultaneously cover multiple error sources was put forward based on basic property of the structure function;established a conversion relation between the structure function and normalized point source sensitivity（PSSn）put forward by TMT team,and then completed the cross validation among the error distribution indexes and transfer of techniques;finally,carried out an error distribution in primary mirror system of a large telescope based on the method put forward in this paper,which indicates that structure function of the system can meet the requirements under the condition where large-scale RMS is25 nm,roughness is 1nm,middle frequency scale is 250 mm and atmospheric coherent length is 0.4m（testing environment）,and that PSSn=0.9996 obtained from the structure function is greater than PSSn=0.999 5directly obtained from mirror data can also meet the corresponding requirement.
作者
安其昌
张景旭
杨飞
赵宏超
AN Qi-Chang ZHANG Jing-xu YANG Fei ZHAO Hong-chao(Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China Graduate University of Chinese Academy of Sciences, Beijing 100039, China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2017年第2期433-440,共8页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.11403022)
关键词
大口径望远镜
标准化点源敏感性
中频误差
结构函数
large telescope
normalized Point Source Sensitivity
middle frequency error
structure function
作者简介
安其昌（1988-），男，山西太原人，博士研究生，助理研究员。2011于中国科学技术大学获得学士学位。2014年于中国科学院大学获得硕士学位，研究方向为大口径光机系统检测装调。
