Real-time simplified correction method for tropospheric refraction error

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.