折射延迟改正模型

Refractive Delay Corrective Model

在分析了一些主要的天顶延迟改正模型,并对几种连分式形式的映射函数模型作了归纳后,认为:前者只能都基于大气球对称分布模型,采用差不多相同的各向同性的改正模型,各种映射函数模型的连分式之间,差别仅是形式上的,没有实质性差异。文章利用普尔科沃大气折射表的表列数据作模拟计算,求解折射率差和映射函数的参数证明,可以用天文大气折射定值作模拟处理,得到折射延迟改正模型中的所有参数,并得出结论:映射函数的形式是次要的,随着项数的增加,都能提高模拟精度。文章给出了模拟过程。

After some major zenith delay corrective models are analyzed and several mapping function models in continued fraction are discussed and induced, it is concluded that the former corrective models are only based on the atmospheric models of spherical symmetric distribution and adopted almost same isotropic corrective models. Also concluded is that distinctions between the mapping function models are just formal but not referring to substance. A simulative computation has been carried out with list data in the Pulkovo refraction table to find refractivity and parameters of mapping function. It is proved that all the parameters in the corrective model can be obtained by the simulation with measured values of the refraction, and concluded that the form of mapping function is secondary, the accuracy of simulation will be improved with increase of the items of continued fraction. The process of the simulation is also presented.