Modeling Global Ionospheric Delay with IGS Ground-based GNSS Observations

Mass ground-based GNSS dual-frequency observations provide a large quantity of data with high temporal and spatial resolution for ionospheric delay modeling.However,the number and the spatial distribution of ionospheric pierce point around the world,and the precision of the dual-frequency observations have great influence on the modeling of the Ionospheric delay.GLONASS/GPS compatible receivers adopted by the IGS stations increase number of available satellites and improve the geometric distribution of IPPs.In view of this advantage,this article mainly focus on combining GPS/GLONASS observations to establish global ionosphere delay model.Data analysis indicates that: ① GLONASS improve global ionospheric mapping under current IGS network.② DCB of GNSS satellites is more stable than those of receivers',DCB of GLONASS satellites is not so good as DCB of GPS.③ There is bigger difference in south hemisphere between WHU and CODE GIM than that of north hemisphere.