Roadmap toward ITRF2020

Since the creation of the International Earth Rotation and Reference Systems Service (IERS) in 1988, 13 versions of the ITRF were published: ITRF88 up to ITRF2014. Each new ITRF solution is demonstrated to be superior to past ones, thanks to continuously improved strategy of the ITRF combination and submitted solutions. The ITRF2014 in particular provides precise quantifications of the coseismic and postseismic displacements and deformations caused by major earthquakes. The next ITRF update is intended to be ITRF2020, expected to be released in 2021. The ITRF2020 will be based on reprocessed solutions of the 4 techniques (VLBI, SLR, GNSS and DORIS). The paper will address a certain number of model updates and effects that are expected to be taken into account by the 4 techniques in their reprocessing efforts. An improved combination strategy will also be operated, including the modeling of station nonlinear motions, the evaluation of technique agreement at colocation sites in linear and nonlinear motions, as well as local ties. Some test combinations will be conducted, in cooperation with some analysis centers of the 4 techniques, in order to evaluate the impact of the model updates on the ITRF results.