Abstract: Tropospheric refraction error is one of the main factors that affect the accuracy of radar measurement and positioning system. In view of the poor real-time and low resolution of the Vienna Mapping Function 1 (VMF1) in refraction error correction, this paper introduces the GPT2w model that can provide some relevant parameters with a resolution of 1°×1°, and build a new model that named as SG-VMF1 by combining with the Saastamoinen model. Based on the new model and the calculation principle of the mapping function method, the tropospheric refraction error values of 4 International GNSS Service (IGS) stations at different elevation angles are estimated. The results demonstrate that when taking the results calculated by ray-tracing method based on IGS meteorological data as a reference, the RMS with the result of SG-VMF1 model and relevant calculation theory can reach 0.4 m when the elevation angle is 6°, and the RMS can reach 0.1 m when the elevation angle is greater than 30°. The new calculation method is feasible and effective, and with real-time and higher resolution.