CHANGING THE GEODETIC INFRASTRUCTURE
Mikael Lilje · 2004
SUMMARY The national reference frames in Europe are going from being national and more or less unique to national realisations of the European reference frame ETRS 89. Sweden is e.g. changing from the reference system RT 90, which is based on Bessel ellipsoid 1841, to a national realisation of ETRS 89, called SWEREF 99. Sweden is also at the same time introducing a new height system called RH 2000, that is the national realisation of the European height system EVRS 2000. The access to reference frames has traditionally been using points in a dense network spread over the region or nation and measurements from these. The introduction of permanent GPS station for surveying and mapping has also made the access to the reference frames much easier for the users. In Sweden, the net of permanent GPS stations is called SWEPOS ™ . Since the 1 st of January 2004 Lantmateriet introduced a network-RTK service over a large part of Sweden making it even easier for users to access the national reference frame.