Impact of the May 2024 Solar Storm on an Undersampled Ionospheric Threat Model for the Korean Region

Ju-Yeong Yu, Eugene Bang*

Ionospheric delay is one of the dominant error sources to single-frequency GNSS users. To mitigate the ionospheric error and ensure user safety, Satellite-Based Augmentation Systems (SBASs) compute and broadcast vertical ionospheric delay corrections and integrity bounds called the Grid Ionospheric Vertical Error (GIVE) at Ionospheric Grid Points (IGPs). The primary contributor to the GIVE bound is the undersampled ionospheric irregularity threat model, which is designed to protect users against severe ionospheric gradients that may not be detected by SBAS reference stations. Since the existing Korean regional overbounding model is empirically constructed from historical observables, the recent May 2024 G5 geomagnetic storm motivates a re-examination of the model. Accordingly, using GNSS measurements from the Korean CORS network, we performed data-deprivation simulations to characterize the worst-case undersampled ionospheric irregularity threats during the storm period. It was found that specific storm- associated threat points exceeding the existing bounds were identified under particular Ionospheric Pierce Point (IPP) geometry conditions.
Keywords: SBAS, undersampled ionospheric irregularity, Korean region

Speaker 유주영 경상국립대학교