Signal deviation is a systematic error which must be controlled and compensated precisely for satellite navigation ionospheric and precise positioning applications. As one of IGS multi-mode GNSS deviation analysis centers, Chinese Academy of Sciences has provided IGS GNSS relative formal deviation DCB and absolute formal deviation OSB products since 2016, covering all open frequency points and signals of BDS2/3, GPS, GLONASS, Galileo and QZSS.
By using Beidou /GNSS, ocean altimeter, DORIS and other high-precision data, combined with global spherical harmonic model, regional improved spherical harmonic model and local generalized trigonometric series model, a fast and accurate spatial ionospheric approach modeling method based on "pseudo-stability idea" was established. An accurate ionospheric simulation and efficient correction model of "global precision - regional refinement - local refinement" has been formed.
Ionospheric gradient, scintillation and other disturbance effects are one of the most difficult problems restricting the accurate and reliable service of Beidou /GNSS. A perturbation fine detection method based on ROTI, GIX, AATR, amplitude and phase scintillation index was constructed to make full use of the regional/global intensive real-time GNSS observation resources. Real-time monitoring, accurate modeling and short-term prediction of ionospheric gradient and scintillation effect were realized.
Fine monitoring and error control of space ionospheric delay, gradient and scintillation effects are very important for navigation and communication applications. Based on ground-based GNSS/DORIS, ocean altimetry and low-orbit occultation ionospheric observation data, ARTEMIS real-time ionospheric correction data service performance and its influence on precise positioning were analyzed.