Impacts of the May 2024 Extreme Geomagnetic Storm on Global High‐Accuracy GPS Positioning Solutions

Abstract

Abstract The May 2024 geomagnetic storm has been recognized as the most severe one in the past two decades and was categorized as an “extreme” (G5) event according to the NOAA space weather scales. This study applies Precise Point Positioning (PPP) software PRIDE PPP‐AR to over 5,800 worldwide GNSS receiver data to highlight the vulnerability of high‐accuracy Global Positioning System (GPS) applications to the hazards posed by ionospheric responses during this unprecedented storm. The observations from these worldwide receivers reveal a strong correlation between ionospheric disturbances, GPS PPP solution inaccuracies, and position outages with SYM‐H index variations. While the overall receiver network is unevenly distributed, significant hemispheric asymmetries in ionospheric response and their impacts on PPP were observed during different phases of the storm. The receivers located in the Northern Hemisphere (NH) experienced PPP outages extending to magnetic latitudes as low as 49°N and lasting ∼15 hr, while the impact on those in the Southern Hemisphere (SH) reached ∼48°S and persisted for ∼20 hr. The North American sector in the NH experienced more severe PPP outages due to combined effects from northward expansion of the equatorial ionization anomaly, post‐sunset instabilities, storm enhanced density, traveling ionospheric disturbances, and equatorward expansion of auroral activities, particularly during the second and third main phases. The Australian sector in the SH also experienced prevalent PPP outages in association with pronounced ionospheric disturbances. The study attributes the pronounced PPP outages to GPS carrier phase cycle slips detected in the PRIDE PPP‐AR processed output. Future research should develop a robust mathematical model and quality control scheme for high‐precision positioning, accounting for diverse ionospheric variations during geomagnetic storms.