A Regional ITRF Densification by Blending Permanent and Campaign Data — The CEGRN campaigns and the Central European Velocity Field

The CERGOP Project of the Central European Countries initiated six GPS observation campaigns from 1994 to 2001. By the high standards set within this project for site selection, observation and analysis a consistent set of epoch solutions with a precision in the 3–5 mm range was created. The network contains about 19 permanent and 38 epoch stations. In this paper a first combination solution over the seven years with a velocity field in the ITRF2000 is presented. It is based on the IGS and EUREF permanent sites and is analyzed in view of its consistency with ITRF2000 for common sites, with respect to time series for the individual stations and for the difficulties stemming from eccentricities required at some sites. Estimated velocities are at or below the 1 mm/yr accuracy level for the main sites and are consistent with the EUREF Permanent Network results. The final velocity field is to be published at the end of this year and will be used for the densification of the ITRF in Central Europe and for the analysis of geokinematics in that area.