Good performance, less computation: A new ionospheric model for the Galileo Open Service

A new ionospheric model called NTCM G (Neustrelitz TEC Model) is now available on the European GNSS Service Centre (GSC) website (https://www.gsc-europa.eu/news/) for correcting ionospheric delay of single-frequency Galileo signals. Investigation shows that NTCM G requires less computing resources compared to the existing reference NeQuick G model while providing a good performance to single-frequency Galileo users. NTCM G does not replace the NeQuick G, but offers an alternative with reduced computational load and complexity for certain users. The NTCM G model was developed by the German Aerospace Centre (DLR) and validated by the Joint Research Centre (JRC) of the European Commission with the support of the European Space Agency (ESA). The description of the source code and its implementation were carried out jointly between DLR and JRC, with the European Union Agency for the Space Programme (EUSPA) and ESA supporting the review and the publication of the model description. The reference implementation of the core algorithm and the auxiliary functions are available for download on the GSC website. The software package provides a portable and validated C/C++ implementation (Matlab and Simulink implementations are also available), including testing functions and testing vectors. NTCM G uses the same Az coefficients broadcast for NeQuick G by the Galileo space segment. Since the Az coefficients are computed in the Galileo ground segment a few hours before the NTCM G works as an ionosphere prediction model for its users.