IGS repro3 products by Graz University of Technology (TUG): Clock errors

The third reprocessing campaign (repro3) of the International GNSS Service (IGS) aims to to provide a time series of consistently reprocessed GNSS products covering the time period 1994-2020. The products are based on updated background models and processing methods. One of the main goals is to support the determination of the next International Terrestrial Reference Frame (ITRF2020) by providing daily coordinates for a global network of GNSS ground stations.

This data set represents the GNSS satellite and station clock error part of the overall contribution of Graz University of Technology (TUG) to IGS repro3. It contains clock errors of GPS, GLONASS, and Galileo satellites as well as ground-based stations for the time period from 1994 to 2020. Next to GPS, which spans the full period, GLONASS satellite clock errors are available starting from 2009 and Galileo clocks from 2013. Station clock errors are only provided for a subset of stations connected to Hydrogen masers or timing laboratories. Clock errors are given at a 30-second sampling period.

TUG's contribution to repro3 was computed using the open-source software GROOPS. The processing included all available stations from the proposed repro3 station list (1212 stations), reaching more than 800 stations per day in the mid-2010s. All available code and phase observations on all frequencies (except Galileo E6) have been used at the full 30-second sampling period.

The following background models and corrections were used during the processing:

• Earth rotation: IERS 2010 plus high-frequency EOP model (Desai and Sibios, 2016)
• Earth's gravity field: GOCO06s plus C20 replacement from SLR
• Moon, Sun and planet ephemerides: JPL DE421
• Solid Earth tide: IERS 2010
• Ocean tide: FES2014b
• Pole tide: IERS 2010 (linear mean pole)
• Ocean pole tide: Desai (2004) (IERS 2010, linear mean pole)
• Atmospheric tides: AOD1B RL06
• Relativistic corrections: IERS 2010
• Tropospheric corrections: VMF3
• Solar radiation pressure: Box-wing + ECOM2
• Earth radiation pressure: Box-wing
• Antenna thrust: Steigenberger et al. (2017)