Global Ionospheric Modeling Using Multi-GNSS: BeiDou, Galileo, GLONASS and GPS
The emergence of Chinaโs Beidou, Europeโs Galileo and Russiaโs GLONASS satellites has multiplied the number of ionospheric piercing points (IPP) offered by GPS alone. This provides great opportunities for deriving precise global ionospheric maps (GIMs) with high resolution to improve positioning accuracy and ionospheric monitoring capabilities. In this paper, the GIM is developed based on