DTRF2020_u2023: The Update of DTRF2020

To update the ITRS 2020 realizations which are based on observations from the geodetic space techniques VLBI, SLR, GNSS and DORIS until the end of 2020, the ITRS Product Center asked the Technique Centers (TCs) for an extension of these series by as consistent as possible operational series. However, the GNSS input series which formerly realized an own GNSS scale, the full history of data was recomputed by the IGS TC by adopting the ITRF2020 scale based on the VLBI and SLR scale contributions.

DTRF2020, calculated by DGFI-TUM, realizes the scale from VLBI and GNSS contributions and thus needs for its update IGS/GNSS series realizing the GNSS scale. Therefore, the IGS TC provided, in addition, an extension series consistent to the input series for the ITRS 2020 realization. Moreover, the GGFC provided extensions of the previous non-tidal loading (NTL) displacement time series as well as time series for new stations to be used in the DTRF2020 update to reduce non-linear station motions.

We extended the DTRF2020 by using the provided extension series and the NTL input data until 2023. We analyzed the extended station position, datum parameter (origin and scale) and Earth Orientation Parameter time series, introduced additional discontinuities and accounted for post-seismic deformation of stations affected by earthquakes.

We present the DTRF2020 update solution (i.e. DTRF2020-u2023) and discuss the consistency of the former and the extension series. In addition, we discuss the results of comparisons of the updates computed by the three ITRS Combination Centers, which reflect the internal accuracy achieved by today's ITRS realizations.