提高中性大气折射延迟改正精度的可能途径  

A Feasible Way for Improving the Correction Accuracy of Neutral Atmosphere Refraction Delay

作　　者：冒蔚[1] 张捍卫[1] 李彬华[2] 杨磊[1] 铁琼仙[1] 

机构地区：[1]中国科学院国家天文台云南天文台,昆明650011 [2]昆明理工大学信息工程与自动化学院,昆明650041

出　　处：《天文学报》2006年第4期432-440,共9页Acta Astronomica Sinica

基　　金：云南省基金(2005A0010R)资助项目

摘　　要：针对空间大地测量技术对中性大气折射延迟改正精度的要求,阐述了折射延迟改正值应随测站和随方位而异的必要性．指出,在尚不能直接测定天文大气折射值的情况下,现有的各种改正模型对大气分布模型的依赖性,不能达到预期的精度和降低观测的截止角．根据云南天文台低纬子午环的特殊结构,和测定大气折射的实践,提出了提高折射延迟改正精度的新方法,即：利用各观测站不同方位从天顶附近直到低地平高度角的天文大气折射实测数据,求解得到折射率差和映射函数的参数,从而建立随测站和随方位而异的大气折射延迟改正模型．这一新方法的实施,将能在不需采用大气分布模型的情况下,把天顶延迟的改正精度提高到1 mm以内,低地平高度角的折射延迟改正精度提高到厘米级,并且把截止高度角压缩到5°以内．Based on the light of the requirements of space geodesy for the correction accuracy of neutral atmospheric refraction delay, it is necessary to put that the refraction delay correction value should change with the station and azimuth. Under the condition that the astronomical atmospheric refractive value can＇t be directly determined yet, the reason why the available various correction models can not meet the anticipated requirement of accuracy and reduce the cut-off height angle for the dependency of the correction values on the model of atmospheric distribution are pointed out. On the special structure of the Lower Latitude Meridian Circle and the practice of determining astronomical refraction in Yunnan observatory, a new method for improving the correction accuracy of the atmospheric refraction delay is proposed： the determined data of the astronomical atmospheric refraction values with different azimuths are utilized to find the refractivity and the parameters of mapping functions for modeling the atmospheric refraction delay correction, which changes with the observing stations and azimuths. Under the condition that the adoption of the atmospheric distribution model is avoided the implementation of this new method will improve the correction accuracy of the zenith delay within lmm,that of the refraction delay of centimeter＇s magnitude, at low altitude angle, and reduce the cut-off height angle by degree 5 or less.

关 键 词：天体测量学 中性大气 折射延迟 

分 类 号：P128[天文地球—天体测量]