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Description & Download

The EUREF reference frame product provides the most accurate positions and velocities for the EPN GNSS stations.

The EUREF reference frame solution is designed for maintaining the ETRS89 and it provides the positions and velocities of the EPN reference stations to be used to align of a GNSS network into the ETRS89 or ITRS.

The Tool for Reference Station Selection based on the station classification of the EPN stations is available to help the users select the most suitable EPN reference stations for their specific project.

EPN station positions and velocities

This preliminary solution is a multi-year position and velocity solution computed with the CATREF software (Altamimi et al., 2007). The positions and velocities are aligned to the IGc20 reference solution under minimal constraints using 14 transformations parameters (translations, rotations, scale and their rates) on a selection of IGc20 reference stations.

Discontinuities
During the stacking, position and velocity discontinuities (discontinuity file) are introduced to account for sudden position change or velocity change in the position time series. A new station position and velocity is estimated after each discontinuity and the velocities are usually constrained to be equal before and after a discontinuity.
Post seismic deformations
In addition, this solution incorporates the ITRF2020-u2024 post-seismic deformation models for 3 stations: ISTA00TUR, REYK00ISL, TUBI00TUR.
Collocated stations
Also, except in cases of significant disagreements, the velocities of collocated sites are constrained to be the same.
Input Files
The EPN multi-year solution, is computed using the EPN daily combined SINEX files:
  • from GPS week 834 up to GPS week 2237, the daily SINEX from the EPN-repro3 computed using the epn_20.atx calibration file
  • after GPS week 2238, the operational daily EPN combined SINEX files computed using the epn_20.atx calibration file.

The reference frame product is available from the directory: https://epncb.oma.be/pub/product/referenceframe/.

The Reference Frame Product product consists in:

Positions & Velocities of EPN stations with more than 3 years

The positions and velocities of the EPN stations with more than 3 years of observations and without modelled post-seismic deformations are provided in the SNX and SSC format and are expressed in 4 different reference frames ITRF2020(IGc20), ETRF2000, ETRF2014, ETRF2020.

SINEX Format SSC Format
ITRS (IGc20 realization) EUR0OPSSNX_1996001_2025270_00U_SOL.SNX.gz EUR0OPSSNX_1996001_2025270_00U_SOL.SSC
ETRS89 (ETRF2000 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2000.SNX.gz EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2000.SSC
ETRS89 (ETRF2014 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2014.SNX.gz EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2014.SSC
ETRS89 (ETRF2020 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2020.SNX.gz EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2020.SSC

Under test: For Bernese users, a CRD (EUR0OPSSNX_1996001_2025270_00U_SOL.CRD) and a VEL (EUR0OPSSNX_1996001_2025270_00U_SOL.VEL) file are available for all the stations observed within the last 270 days. For each station, the position and the velocity of the last available solution number is given.

Positions of other EPN stations

The positions of the stations with less than 3 years of observations and of the 5 stations with modeled post-seismic deformations (ANKR00TUR, BUCU00ROU, ISTA00TUR, REYK00ISL, TUBI00TUR) are only provided in the SSC format and expressed in 3 different reference frames: ITRF2020(IGc20), ETRF2000, ETRF2014, ETRF2020.

SSC Format
ITRS (IGc20 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_short.SSC
ETRS89 (ETRF2000 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2000_short.SSC
ETRS89 (ETRF2014 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2014_short.SSC
ETRS89 (ETRF2020 realization) EUR0OPSSNX_1996001_2025270_00U_SOL_ETRF2020_short.SSC

Extended Position Time Series of EPN Stations

Each day, the EPN CB extends the multi-year EPN time series with recent EPN solutions to enable a quick monitoring of the EPN station positions. In practice, currently, the multi-year EPN solution from GPS week 834 till 2385 has been extended in time using the operational daily combined EPN solutions from GPS week 2386 till 2405 and the rapid daily combined solutions from GPS week 2406 till 2413.

Dynamic plots of the extended position (in ITRF2020 and ETRF2020) and residual position time series are available online.

EPN discontinuities
EPN_discontinuities.snx contains a catalogue of all discontinuities observed in the EPN multi-year solution. It defines the solution numbers (soln) used in the EUREF Reference Frame solution. The list has been as much as possible harmonized to agree with the IGS/ITRF discontinuity table. Unfortunately, some stations still disagree due to different period of observations.
Outliers
EPN_outliers.lst contains the list of positions removed from EPN daily combined SINEXs before the multi-year combination.
Miscellanous plots
Archive of the previous solutions

Please cite the EPN Multi-year Position and Velocity Solutions as:
Legrand J. (2022): EPN multi-year position and velocity solution CWWWW, Available from Royal Observatory of Belgium, https://doi.org/10.24414/ROB-EUREF-CWWWW.