Refractive Delay Corrective Model

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.