基于畸变梯度重构畸变的在轨标定方法

On-orbit Calibration method based on distortion gradient Reconstructiondistortion

摘要:

微角秒测量精度的相对天体测量法可用于探寻近邻宜居行星,相应的,光学望远镜有效载荷的畸变在轨标定精度也需要达到微角秒量级。传统的光学望远镜在轨畸变标定方法普遍依赖于恒星方向信息,而现有星表中恒星赤经、赤纬的精度最高达到毫角秒量级,无法满足微角秒量级标定的要求。本文提出一种基于畸变梯度重构畸变的在轨标定方法,该方法充分利用微角秒测量精度的星间距测量技术,不受恒星赤经、赤纬精度的限制,能使望远镜光学畸变的标定精度达到微角秒量级。文章介绍了基于畸变梯度重构畸变的原理,并对由光学设计软件导出的光学系统进行了畸变标定仿真实验,结果表明：当光学系统波像差控制在0.0733λ内且星角间距测量误差为0.3微角秒时,畸变标定精度可达0.28微角秒,满足近邻宜居行星探测的畸变标定要求。

Abstract:

The relative astrometric method of microangular second measurement accuracy can be used to explore neighboring habitable planets. Accordingly, the in-orbit calibration accuracy of optical telescope payload distortion needs to reach the order of microangular seconds. The traditional on-orbit distortion calibration methods of optical telescopes generally rely on the star direction information, but the accuracy of star right longitude and declination in the existing catalogue is up to the order of milliseconds, which can not meet the requirements of micro-angle-seconds calibration. In this paper, an on-orbit calibration method based on distortion gradient reconstruction distortion is proposed. this method makes full use of the star spacing measurement technology of microangular second measurement accuracy, does not need to use star catalogue, and is not limited by the accuracy of stellar right longitude and declination. The calibration accuracy of optical distortion of the telescope can reach the order of microangular seconds. In this paper, the principle of distortion reconstruction based on distortion gradient is introduced, and the distortion calibration simulation experiment is carried out on the optical system derived from the optical design software. the results show that when the wave aberration of the optical system is controlled within 0.0733 λ and the measurement error of star angle spacing is 0.3 microangular seconds, the distortion calibration accuracy can reach 0.28 microangular seconds, which meets the distortion calibration requirements of nearest neighbor habitable planet exploration.