EPN-Repro3: Improved Maintenance of Regional Reference Frames Through Standardized and Complete Reprocessing of all Available GNSS Data (1996-Present)
摘要
The European Terrestrial Reference System (ETRS89) is the European Union recommended European geodetic reference system. It is based on the global International Terrestrial Reference System (ITRS), but is fixed to the stable part of the Eurasian tectonic plate. The ETRS89 is realized through the EUREF Permanent Network (EPN), which has been operational since 1996. Today, the EPN includes more than 420 active GNSS (Global Navigation Satellite System) stations spread across almost all of Europe. Since the EPN was set up, a number of improvements have been implemented in the computation standards related to data processing and analysis, the introduction of new satellite navigation systems, such as GLONASS and Galileo, and in antenna and receiver technology. For the maintenance and further development of the reference frame, homogeneous position time series are crucial, but these are affected by the successive modernizations and reference frame updates. Therefore, analogously to the IGS (International GNSS Service), EUREF decided to reprocess all available GNSS data since 1996 in a standardized and homogeneous way. In contrast to our previous work, EUREF stopped using individual antenna calibrations and now uses type mean calibration only. This is motivated both by the need for harmonisation with the IGS and by the fact that many individual antenna calibrations do not contain calibrations for GLONASS and Galileo with their full frequency spectrum. Analysis Centres (ACs), participating in the EPN-Repro3 campaign, computed a sub-network of overlapping EPN stations on a daily basis, providing SINEX solutions that are combined in daily solutions by the EPN Analysis Centre Coordinator. Using these combined solutions, the EPN Reference Frame Coordinator estimates a cumulative multi-year position and velocity solution aligned to the IGS20.