Impacts of the Great May 2024 Geomagnetic Storm on Precise Point Positioning

The adverse effects of space weather can be one of the main threats to human technology, such as the effects of large coronal mass ejections. Consequently, great geomagnetic storms can compromise the performance of Precise Point Positioning (PPP). Recently, after over two decades, on 05/10/2024, the main phase of a great and exceptional geomagnetic storm began, providing an excellent and rare opportunity to study its effects on the PPP using the CSRS-PPP online service. This work aims to evaluate the impacts of the great storm on three-dimensional accuracies, percentage of ambiguity resolution, and cycle slip, encompassing five days of processing, covering two days before the storm, one day coinciding with the main phase of the storm, and two days after the storm, coinciding with the recovery phase. The processing was carried out at an interval of 1 hour, from 23-24 UTC, coinciding with the main phase (05/10/2024), as the adverse effects of the storm manifest themselves in this phase. Data from 20 GNSS stations from the Brazilian Network for Continuous Monitoring of GNSS Systems were used. During the main phase of the storm, the average three-dimensional accuracy increased around four times compared to the previous day. The percentage of ambiguity resolution was equal to 0.0% for all stations analyzed. Furthermore, cycle slips increased significantly during the main phase of the storm. In summary, the results highlight the adverse impacts of the great and exceptional storm on the PPP.