Simulation of Equatorial Plasma Bubble Signatures in GNSS TEC

Abstract

Equatorial plasma bubbles (EPBs) are ionospheric plasma depletions that can disrupt Global Navigation Satellite System (GNSS) signals and degrade positioning at equatorial and low latitudes. Evaluating total electron content (TEC)-based EPB detection using observations is challenging because GNSS links provide sparse, geometry-dependent sampling, and the three-dimensional structure of EPBs is generally unknown. This study develops a controlled forward modeling framework for simulating and detecting EPB signatures in GNSS slant TEC (sTEC). Global-scale Observations of the Limb and Disk (GOLD)-derived parameterised depletions were embedded in a three-dimensional Neustrelitz electron density model (NEDM-2020) background ionosphere, and sTEC was integrated along simulated receiver and satellite ray paths. Depletion events were identified from detrended sTEC, mapped to ionospheric pierce point coordinates, and combined across multiple satellite links using a declination-guided clustering and grouping procedure. The prescribed signatures were detected under static and uniformly drifting conditions. The tested horizontal-geometry and drift-speed cases remained detectable, whereas no event satisfied the detection criteria at the lowest depletion-amplitude scaling factor of 0.50 applied to the GOLD-derived depletion amplitude. In 30 Gaussian noise realisations at each non-zero noise level, the nominal PRN 23 depletion was recovered in 17, 6, and 1 runs at noise standard deviations of 0.10, 0.25, and 0.50 TECU, respectively. An adapted slope-and-variance-based method identified the PRN 10 depletion in the static case but did not retain a valid depletion event in the drifting case. The framework provides a controlled testbed for evaluating EPB detection and localisation under known simulated conditions. Evaluation using real GNSS observations and independent measurements is required to assess its performance under observational conditions.