Global reference frames

(in the IERS Terrestrial Reference System (ITRS))

Three-dimensional reference frame based on the definition of the International Earth Rotation Service.

In close cooperation with all European geodetic institutions, the Subcommission EUREF of the Association for Geodesy (IAG) realized the following reference frame:

(in the European Terrestrial Reference System 1989 (ETRS89))

Three-dimensional reference frame based on the European GPS reference network EUREF and covering the entire European continent. Switzerland is connected to this frame with five reference points.

The Swiss national survey provides the following global reference frames:

(in the Swiss Terrestrial Reference System 1995 (CHTRS95))

Three-dimenstional reference frame based on the GPS national network of 104 main and 103 densification points, and the permanent GPS network AGNES (31 automatic stations). The coordinates are in the system CHTRS95. The highly accurate reference frame fulfills all of the demands with respect to the absolute accuracy and reliability of the coordinates on the cm level. The exact transformation ETRFyy CHTRFyy is guaranteed.

According to the definition in the time-dependent system CHTRF95, CHTRFyy is a data set which refers to the epoch t 0 = 01.01.19yy and 01.01.20yy respectively. New sets of coordinates (e.g. CHTRF95, -98, -2004) are determined through periodic remeasurements and adjustments of the geodetic networks and made available for special applications (large engineering surveys such as BAHN2000 or AlpTransit).