Global mapping of total electron content from GNSS observations for updating IRI-Plas model

Global median empirical model of Total Electron Content (GTEC) is developed driven by re-calibrated sunspot numbers, SSN2, for the quiet geomagnetic conditions (ap < 15 nT). The based on Spherical Harmonic Analysis (SHA) Ionospheric Maps GIM-TEC provided JPL from 1996 to 2019. SHA coefficients are calculated low solar activity (SSN2 ? 20) and high ? 100) linear interpolation applied between them. input parameters geographic coordinates, time UT, day, month, year, number SSN2. GTEC mapping accuracy validated comparing results GTEC, IRI-2016 IRI-Plas models with independent observed UPC four seasons local moderate (2012). testify that shows Root Mean Square Error, RMSE, about 2 times less than TEC predictions. Model can be used alone prediction under conditions. It also incorporated as an option code improve predictions model.