Regional Medium‐Scale Traveling Ionospheric Disturbance Propagation Model Based on BDS GEO Satellites

Abstract Accurate modeling of traveling ionospheric disturbances (TIDs) is essential for characterizing their spatiotemporal variations and mitigating their effects on Global Navigation Satellite System (GNSS) precise positioning. This study develops a regional medium‐scale TID (MSTID) propagation model using BeiDou geostationary orbit (GEO) total electron content (TEC) data. First, we propose a singular spectrum analysis (SSA)‐based interpolation method to reconstruct the possible data gaps of BDS GEO TEC time series, enhancing its TID detection stability. Second, we select well‐distributed GNSS reference stations in Hong Kong, grouping them into triplets to estimate average TID parameters (main frequency, amplitude, velocity, and direction) using cross‐spectral analysis. Finally, a regional MSTID propagation model is constructed using a cosine function, incorporating the average phases, frequency, and amplitudes. The model was firstly validated through the measured TID signal from the HKSC, HKST, and HKKT stations on 29 October 2018. Results indicate strong agreement between the model‐estimated and measured TID signals. Validation results show the model reduces TID‐induced ionospheric delay errors by 48.2%, 50.3%, and 42.7% without accounting for the time lag and further by 55.0%, 53.1%, and 45.1% with optimal temporal alignment for HKSC, HKST, and HKKT, respectively. Another MSTID event on 30 April 2016, was also selected to further validate the general applicability of the proposed TID model under different propagation characteristics. It confirms the model's accuracy and reliability. This study provides an effective approach for precise TID characterization and supports mitigation strategies for GNSS positioning errors caused by traveling ionospheric disturbances.