Observations of traveling ionospheric disturbances over Ukraine during geospace storm using single GNSS receiver

We proposed a simplified technique for detecting large-scale traveling ionospheric disturbances (TIDs) based on data from a single GNSS receiver. This method enables an approximate determination of the zonal or meridional propagation of TIDs when satellite trajectories are predominantly aligned along parallels or meridians. We identified large-scale TIDs during the passage of the sunrise solar terminator and enhanced auroral activity. These disturbances exhibited dominant periods of approximately 60 min, with amplitudes ranging from 0.2 to 0.25 TECU (1 TECU = $10^{16}$ $m^{-2}$). TIDs induced by space weather variations mainly propagated along the meridians, whereas the propagation direction for TIDs generated by the sunrise solar terminator could not be determined. Comparison with incoherent scatter data revealed good agreement in the periods and observation intervals of the TIDs. Furthermore, incorporating GNSS data from the European dense GNSS receiver network validated the inferred directions of TID propagation.