Global Ionospheric TEC Modeling Using Measured GPS and GLONASS

According to the requirements of high precision satellite navigation and ionosphere activity monitoring, double-frequency measurement data from 238 IGS stations are used to calculate vertical ionosphere electron content (VTEC), DCB of GPS, GLONASS and the corresponding receiver based on the spherical harmonic function model. The results show that this implemented model is reliable. The DCB precision of GPS and GLONASS obtained is less than 0.1 ns when compared with the results of CODE and less than 0.2 ns when compared with that of IGS. The DCB precision of GPS and GLONASS receivers are less than that 2 ns, while the precision of VTEC is better than 3 TECU in comparison with that of CODE and IGS, and better than before combination.