Regional Ionosphere Modeling Based on Multi-GNSS Data and TPS Interpolation

GNSS signals have become a valuable tool in studying the Earth's ionosphere as their dual-frequency observables allow for calculation ionospheric total electron content (TEC). Recent studies estimated relative error of popular GNSS-TEC maps at the level of 20-30 %. This motivates research community to develop new modelling and interpolation methods. In this paper, we demonstrate new approach to GNSS-TEC estimation. In the new approach we use solely carrier phase multi-GNSS observables and thin plate splines (TPS) for accurate ionosphere modeling. The model allows for providing TEC maps for Europe with high spatial and temporal resolutions - 0.2x0.2 degrees and 2.5 minutes, respectively. In addition, we present the performance of our approach during one the most intense ionospheric storms of 24th Solar cycle that took place in March 2015. The results showed that the accuracy of our maps was better with residuals lower by at least 50 % comparing the widely used product.