Real-time monitoring of the ionospheric state with the use of a 3D assimilation model

The 3D assimilation ionospheric model is improved to assimilate in real time the ionospheric total electron content (TEC) measurement data from the International GNSS Service (IGS) network of ground-based stations of the global positioning system (GPS). This model makes it possible to calculate the space-time electron-concentration distributions of electrons, concentration of the seven main ions, and the temperature and velocity of electrons and ions in the ionosphere at altitudes of 100–1000 km. The model calculations of the ionospheric TEC are compared to the TEC measured on slant paths with the use of two-frequency receivers of the ground-based IGS network of stations not included into the assimilation scheme. The model calculations of ionospheric electron-concentration height profiles are compared to the data measured by an incoherent-scatter radar. It is shown that the ionospheric parameters calculated without using experimental data are in worse agreement with the radar measurement data than the results obtained with the assimilation model of the ionosphere. The model-calculated electron concentrations are compared to the data from the FORMOSAT-3/COSMIC system of medium-Earth-orbit satellites.