中文摘要：

针对中性大气的物理属性以及大气折射对射电望远镜指向的影响进行了模型分析和计算,以改进型的“三段式”标准指向改正模型为基础,着重研究了由大气折射造成高阶指向误差的改正方案,目的是不断提高射电望远镜的指向精度,尤其针对大口径、高分辨率的射电望远镜。在此模型的基础上,模拟南山观测基地的气候特征,给出合理的计算结果。通过分析和评估这些结果与射电望远镜指向精度的要求,为将来大口径射电望远镜的指向修正提供参考。

英文摘要：

In this article we discuss the effects of the atmospheric refraction, particularly, the method of accurate corrections to the pointing error of radio telescopes. The position of the telescope beam is somewhat different from the beam position as indicated by the encoders, which is due to the structural deformations caused by the wind, gravity, temperature, and the atmospheric distortion. Accurate refractive corrections which depend on astronomical pointing measurements are required by observations using large aperture radio telescopes, especially at higher frequency bands. This article presents the advanced model for atmospheric refraction corrections and shows the improvements compared to traditional methods, particularly at low elevations. In addition, the real-time refraction Corrections, in which the higher-order refraction corrections of telescope pointing errors are involved, for example, the effect of the uneven temperature distribution over a wide scale range, or the differential refraction across a large aperture telescopes, are also analyzed in this article.