The G4 Solar Storm of May 2024: Impact on the GNSS Carrier-Phase Measurements

GNSS constitutes the main positioning system worldwide. Despite its importance in everyday life, there are still some challenges that limit the use of such systems in every condition; one of this is the intense solar activity. The interaction between the Sun Coronal Mass Ejection and the Earth magnetosphere causes ionospheric disturbances that influence the propagation of GNSS signals. This effects worsen the PVT solution accuracy, and need to be investigated. For this reason, the proposed study aims to investigate, at the measurement-level, the impact of the G4 solar storm occurred in May 2024, by inspecting the carrier-phase before, during and after the storm. Several IGS stations spread around the world have been considered and the effects of the solar storm have been evaluated in terms of cycle slips, Weighted-Least-Square residuals, TDCP solution errors. From the results, it emerged that the impact of the solar activity peak is more visible at high latitudes, while disperse or almost null effects are reported at lower latitudes.