First Results of the GNSS Reprocessing at the University of Luxembourg for an Updated Global Vertical Land Movement Data Set

The University of Luxembourg (UL) is currently contributing to the most recent reprocessing effort of the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring Working Group (TIGA-WG) with multi-constellation GNSS solutions, including GPS, GLONASS and Galileo. As part of this new reprocessing and reanalysis effort of GNSS data including stations at or near tide gauges worldwide, several model enhancements consistent with the IGS’s recent effort have been incorporated. During 1994 to 2022 the network generally contains data from over 700 stations. The IGS has placed high importance on unifying processing standards because homogeneous and consistent reprocessing of all GNSS data over the complete time span is necessary for estimating useful geophysical parameters, such as long-term trends in station positions. In addition to the reprocessing of the data, the time series analysis strategy is crucial for deriving accurate long-term estimates. In order to obtain the best parameter estimates and the most realistic uncertainties, it is anticipated that a number of stochastic and deterministic models will be fitted to the position time series. Additionally, the stochastic properties of the series will be investigated. Existing automated processes will be updated with the most recent developments in geodetic time series analysis due to the vast number of stations. Through the full reprocessing of all GNSS observations and the state-of-the-art analysis of the daily position time series, this study will be able to obtain highly accurate estimates of horizontal and vertical land movements that can be employed for the most challenging applications such as correcting coastal sea level records for a better understanding in their changes and constraining glacial isostatic adjustment models. During this presentation, we will provide details on the current reprocessing, present preliminary results and a first cross-evaluation of the vertical land movement estimates.