The GNSS solution named ’GT3’ is produced by the German Research Centre for Geosciences (GFZ) for the International GNSS Service (IGS) working group TIGA. It contains position time series for 319 permanent GNSS stations expressed in the ITRF2014 reference frame over the period January 1994 to December 2020.

This GNSS solution was carried out within the framework of the 3rd IGS reanalysis (reprocessing) campaign (Repro3). Among the 319 stations processed by GFZ, as many as 272 have actually been identified as co-located, or nearby, tide gauges.

The GNSS velocities, provided here for 296 stations (nearby tide gauges and reference frame stations included) with a minimum record length of 3 years and data gaps not exceeding 30%, are also produced by GFZ. To be more realistic, constant values (0.1 mm/yr in horizontal and 0.3 mm/yr in vertical) have been added to the formal errors on the velocities.

More details about the GNSS data analysis strategy can be found in Männel et al. (2022).


 Vertical velocities table

The GT3_Vertical-Velocities_Table provides the vertical GPS velocities and uncertainties from the 296 stations fulfilling the criteria of 3 years of minimum length and data gaps not exceeding 30%, estimated by the GFZ group.

 Daily time series

The file contains individual station data files of daily position time series in ITRF2014 with respect to the position at the reference epoch. These positions are expressed in meters in the local frame (North, East, and Up). The reference position and the 3D velocity in the local coordinate system (East, North, Up) are provided in the header of each file.

 Position discontinuities

The GT3_discontinuities_Table.txt file provides the position offsets that have been estimated by the GFZ group.


Männel, B., Schöne, T., Bradke, M., Schuh, H. (2022). Vertical Land Motion at Tide Gauges Observed by GNSS: A New GFZ-TIGA Solution. In: International Association of Geodesy Symposia. Springer, Berlin, Heidelberg.