High Precision Algorithm for Ionospheric VTEC Based on Single Ground-based GNSS Station

Using the dual frequency GNSS observation data provided by IGS, the problems existing in Vertical Total Electron Content (VTEC) calculation using Kalman filtering method were analyzed, Kriging-Kalman algorithm was proposed, and the VTEC calculated by the two methods were compared. The results showed that: in the low latitude region, when the number of satellites in observation changed, the VTEC value calculated by Kalman filter method might have curve fracture anomaly; the VTEC value calculated by Kriging-Kalman method changed smoothly relatively. In addition, the changes of VTEC calculated by two method above during the flare were compared, it found that the change of VTEC calculated by Kalman filtering method was smaller than the increment of VTEC caused by flare, while the result of Kriging-Kalman method was more consistent with the actual change. All the results show that the accuracy of VTEC calculated using Kriging-Kalman method is higher in low latitude area, which can reflect the change of VTEC in abnormal space weather activities more accurately, and conducive to the daily accurate monitoring and engineering application of ionospheric VTEC.