Modelling equatorial plasma bubbles and their impact on GNSS signal propagation

Equatorial plasma bubbles (EPBs) are localized ionospheric plasma density irregularities that can strongly disturb Global Navigation Satellite Systems (GNSS) signal propagation, especially after sunset in equatorial regions. Although EPBs have been widely studied, their complex spatial structure and rapid evolution make it difficult to reliably quantify their impact on GNSS-derived total electron content (TEC).

To address this challenge, a simulation framework is employed in which the background ionosphere is generated using the Neustrelitz Electron Density Model (NEDM), and equatorial plasma bubbles are embedded as localized electron density depletions, with their spatial extent derived from satellite observations. GNSS signal propagation is simulated using satellite ephemeris data to define realistic satellite–receiver geometry, and the total electron content (TEC) is computed along the signal paths. The TECs are analysed as a function of satellite elevation angle to assess the impact of plasma bubble structures on trans-ionospheric signal propagation.

The simulated TEC exhibits pronounced variations when signal paths intersect equatorial plasma bubbles, and the magnitude of these variations strongly dependent on satellite elevation and viewing geometry. Signals propagating at low and oblique elevation angles exhibit the largest TEC perturbations due to extended path lengths through ionospheric irregularities.

By varying the bubble structures in simulation environment, we demonstrated the possibility of determining ionospheric bubble structures by analysing their impact on ionospheric TEC data.