Definition and Realization of Vertical Reference Systems

[摘要] The European Subcommission on Continental Network EUREF was urged by the European Council to deliver European wide solutions for the georeference of common cartographic data. In the field of horizontal reference systems a new solution is available coming from ITRS/ ITRFxx. EUREF has defined the epoch 1.1.1989 as European Terrestrial System (ETRS) in 1989 and realized it as frame (EUREF) by densification and maintenance of the ITRF. Vertical reference systems realized by precise levellings do not allow new continental or global solutions in a short span of time. Therefore existing data with precise levellings was used and combined as United European Levelling Net (UELN) 95/98 (static solution). In addition a geokinematic solution using repeated levellings and also other height relevant