低仰角蒙气差精密修正的新方法

由于蒙气差随着大气密度、温度和压力等条件的变化而变化,为降低蒙气差对光电测量设备测量精度的影响，提出了精密恒星回扫的新方法。在标准大气条件下，通过理论计算得到的蒙气差与实际测量值存在偏差，采用精密恒星星库，引导测量设备对观测目标附近的恒星进行事后回扫测量，对回扫测量数据进行拟合可以得到蒙气差的修正量。分析了恒星回扫方法中影响修正精度的轴系、编码器等因素，通过外场实验，在大气湍流变化均匀的情况下，采用该方法对20°仰角以下星体进行观测，测量精度可以达到1″。

New method of precise correction for atmosphere refraction in low elevation

A new method of precise star back scanning for reducing the influence of atmosphere refraction on the measurement accuracy of opto-electronic instrument is presented.Atmosphere refraction changes with the variation of atmosphere density,temperature and pressure.The atmosphere refraction calculation based on theoretical standard atmosphere differs from that of the real situation.Accurate star library is used to guide the instrument to back scan the stars close to the observed target in real-time,and the correction factor for correcting the atmosphere refraction could be achieved from fitting back scattering data.The factors influencing correct precision are analyzed,such as shafting and encoder.Field experiments in low elevation under symmetrical changed atmosphere turbulence show that the correction precision can reach 1 arc second.