NEUTEC: An Accurate Method for the Global Ionospheric TEC Estimation Using Multi-GNSS Observations

Global GNSS-TEC data derived from NEUTEC for DOY025 to DOY031 in 2023

The NEUTEC project proposes a method for precisely estimating the global ionospheric TEC using multi-GNSS. This method aims to establish more comprehensive constraints by considering the spatio-temporal relationships between satellites, constellations, stations, and time. It strives to accurately estimate the DCB parameters and compute the ionospheric TEC, addressing the inconsistencies and uncertainties commonly present in existing techniques for ionospheric TEC estimation.The dataset processed by the NEUTEC program consists of four main types: IPP, sTEC, vTEC, and Elv.

1) IPP: This dataset contains the latitude and longitude of the ionospheric pierce points for each satellite, in radians. If a data point is missing, the corresponding value is set to 0.2) sTEC Data: sTEC (Slant Total Electron Content) represents the total electron content in the line-of-sight direction observed by a satellite at a specific pierce point, in units of TECu. If the observation is missing, it is marked as NaN.3) vTEC Data: vTEC (Vertical Electron Content) refers to the total electron content in the vertical direction at each satellite's pierce point, also in units of TECu. If the observation is missing, it is represented as NaN.4) Elevation Angle Data (Elv): This dataset records the elevation angle of each satellite during observation, in radians.

For the calculation of epoch time, it can be generated based on the standardized data length. If the data length is 2880, the sampling interval is 30 seconds. If the data length is 5760, the sampling interval is 15 seconds. If the data length is 86400, the sampling interval is 1 second.

For the calculation of azimuth, it can be calculated based on the coordinates of the observation station and the coordinates of the IPP point.

Reference:He, L., Zhang, Y., Qu, Z., & Wu, L. (2025). An accurate method for the global ionospheric TEC estimation using multi-GNSS observations. IEEE Transactions on Geoscience and Remote Sensing. https://doi.org/10.1109/TGRS.2024.3523396