Implementation of ITRF2020 in the ILRS Operational Products

The ILRS contributed to the development of ITRF2020 via the combined products submitted to ITRS. The combined products were the result of the combination of individual AC contributions where a new approach in handling systematic errors at the stations was implemented. A set of a priori estimated mean biases was considered for the main period 1993-2020 that includes data from LAGEOS, LAGEOS-2 and the Etalons, whereas an adjusted 15-day average bias at each station for the 1983-1993 period was considered to accommodate systematic and target signature errors, if a priori mean biases were missing. The implementation of ITRF2020/SLRF2020 in SLR operational products required an extended version of the SSEM model, SSEM-X, which led to the finalization of a new DH file. Considering this updated set of long-term mean biases, all ACs produced a solution set based on models used for REPRO2020 and SLRF2020 as input to a combined product intended for the IERS RS/PC at USNO. These EOP series will be used for the calibration of EOP biases prior to the release the final version of the new Bulletin A. The new bias model SSEM-X will be publicly available and maintained current over the coming years.