This study aims at development of multi‐dimensional integrated model of the ionosphere, by using different space geodetic techniques and applying a combination procedure for computation of global ionosphere models. Geodetic techniques, such as the Global Navigation Satellite Systems (GNSS), satellite altimetry, or FORMOSAT‐3/COSMIC allow the observation and modeling of the ionosphere, but each has its specific characteristics which affect the derived ionosphere parameters. The combined model makes best use of the advantages of every particular method, has a more homogeneous global coverage and is more accurate and reliable than the results of each single technique. In the first step models generated from the combination of GNSS and satellite altimetry within the Institute of Geodesy and Geophysics (IGG), Vienna, are integrated with occultation data from Low Earth Orbiter (LEO) satellites such as FORMOSAT‐3/COSMIC to model ionospheric parameters in terms of the electron density as a function of latitude, longitude, time, and height.
Since these LEO missions observe GPS occultation measurements, they have the capability of providing vertical profiles of ionospheric refractivity and would give the opportunity to develop 4D ionosphere models. For further improvement of the results, the models are integrated with external models and data such as the International Reference Ionosphere (IRI). The integrated combined GIM will be useful for correcting single‐frequency measurements carried out by many observation techniques using radio frequencies and for validation and improvement of ionosphere parameters derived by other individual techniques as well as theoretical models.