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To assign more realistic uncertainties on the GPS velocities, the noise content in the position time series was examined by the maximum likelihood estimation (MLE) technique using CATS software. Time series were detrended and deseasoned (annual cycles) at the CATREF stage. Details on the GPS velocity uncertainty assessment will be given in the below-mentioned paper.

- Vertical velocities table

The ulr4_vertical-velocities_table provides the vertical GPS velocities and uncertainties for the 275 stations fulfilling the criterias of 2.5 years of minimum length without discontinuities and with data gaps not exceeding 30%.

- Weekly residual time series

The ulr4_detrend.zip file contains individual station data files of weekly residual position time series in ITRF2005 with respect to the linear long-term combined solution at the reference epoch. These residuals (detrended and deseasoned) 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. Theulr4.kmz file shows a Google Earth presentation of the above weekly data files by cliking on a station symbol. The associated IGS-like sitelog can be accessed too, as well as a plot of the residual position time series in the vertical.

- Position discontinuities

The ulr4_discontinuities_table.txt file provides the position offsets that were estimated.

- Solution file

The long-term solution ULR4 in SINEX format (47 Mo) can be downloaded too. However, we recommend its use only to those familiar with SINEX files, and having a good geodetic background and experience.