Equatorial plasma bubble model for assessment of GBAS satellite availability

Abstract

One of the main concerns for Ground-Based Augmentation Systems (GBAS) is the occurrence of anomalous ionospheric conditions. In particular, ionospheric scintillation poses a significant threat, as strong scintillation events can cause GNSS receivers to lose signal lock, thereby reducing the number of available satellites for position computation. This often results in a degradation of system continuity and availability. To address this issue, this work develops a methodology to predict GBAS availability at specific airports (e.g., Tenerife Norte Airport) using a DLR-developed dynamical model of Equatorial Plasma Bubbles (EPBs), which are typically associated with scintillation events. Due to the limited number of GNSS monitoring stations surrounding Tenerife Norte Airport—a consequence of its island location and the surrounding oceanic environment—EPBs and the associated scintillation effects are simulated. The proposed approach combines reduced-order EPB modeling with a phase-gradient screen technique to reproduce scintillation generated by steep electron density gradients at EPB boundaries. By integrating these simulations with GISM-based ambient scintillation estimates and a time-varying ionospheric background model, synthetic scintillation indices are derived and subsequently used to assess DFMC GBAS availability.