ITRF2020: an augmented reference frame refining the modeling of nonlinear station motions

Abstract To better describe the shape of constantly deforming Earth’s surface, ITRF2020 is provided as an augmented terrestrial reference frame that precisely models nonlinear station motions for both seasonal (annual and semi-annual) signals present in position time series Post-Seismic Deformation (PSD) sites impacted by major earthquakes. Reprocessed solutions form Earth Orientation Parameters using full observation history four space geodetic techniques (DORIS, GNSS, SLR VLBI) were used input data, spanning 28, 27, 38 41 years observations, respectively. The long-term origin follows linearly with Center Mass (CM) sensed SLR, based on observations collected over span 1993.0–2021.0. We evaluate accuracy evolution comparison to previous solutions, namely ITRF2014, ITRF2008 ITRF2005, be at level or than 5 mm 0.5 mm/yr, scale defined a rigorous weighted average selected VLBI sessions up 2013.75 weekly covering 1997.75–2021.0 span. For first ITRF history, agreement between 0.15 ppb (1 equator) epoch 2015.0, no drift. accommodate most users, coordinate variations are CM well Figure frames, together geocenter motion model. While PSD parametric determined fitting GNSS data only, they also fit three other colocated demonstrating their high performance describing site post-seismic trajectories.