Determining the Astronomical Refraction and Building the Radio Wave Refractive Delay Model Measured(Ⅵ)——Acquisition of Instantaneous Refractions and Refractivity

According to the principle of determining the astronomical refraction, the way to obtain measured values of instantaneous refraction by corresponding observational data is described. Some particular demands on this data-processing are emphasized specially from the relationship between various measured values and the final result. The treatments for correcting the measured refractions according to wavelengths of the observational stars and for building measured refractive delay corrective models are described. Requirements of the corrective model to distribution of the measured values of the refraction are analyzed, and a distribution model of observational data dense with increase in zenith distance is presented.