利用天文观测建立大气折射延迟改正模型

Building measured atmospheric refraction delay model using astronomical observation

大气折射延迟是空间大地测量技术中的主要误差源.完善大气折射理论不仅可以改善数据处理的归算精度,而且有希望降低仪器的观测截止角,提高仪器的使用效应.对中性大气折射延迟的基本概念和理论方法进行了研究,指出目前的天顶延迟模型都依赖于大气分布模型,各种映射函数模型的差别仅是形式上的,没有实质性差异,这就是当前仍然不能改善大气折射延迟精度的主要原因.利用大气折射表的表列数据作模拟计算证明,用天文大气折射测定值作模拟处理的方法是可行的,可以得到大气折射延迟改正模型中的所有参数.同时表明,映射函数的形式是次要的,随着连分式项数的增加可以提高模拟的精度.基于天文大气折射的测定值,给出了建立中性大气折射延迟实测改正模型的过程.

The neutral atmospheric delays is an important error source in the space geodesy. The perfecting to the theory of atmospheric refraction can not only improve computing precision of data processing, but also can reduce instrumental cut - off elevation and make the best of instruments. This paper investigated the basic concept and theoretical method of atmospheric refraction delay, and indicated that nowadays all refraction delay correction models arc depend on atmosphere distributing model. The differences between mapping functions only is modal and haven＇t distinguish in substance. It is the main reason that the precision of atmospherical refraction delay still can not be improved at present. Via simulation reckoning, which using the tabled da- tum of atmosphere refraction values, the use of surveying values of atmosphere refraction to simulate refraction delay is proved feasible, and all parameters in atmosphere delay correction model can be obtained. Meanwhile, the format of mapping function is indicated secondary, which along with increase of terms in continue fraction, and the precision in simulation process can be improved. Based on surveying value of atmosphere refraction, an approach of establishing the surveying correction model of neutral atmosphere refraction delay has been given.