Results of the WEGENER / GPS - 92 Campaign

During the International GPS Service for Geodynamics (IGS) Epoch’92 campaign a special sub-campaign was organized to occupy all WEGENER/MEDLAS SLR sites with Trimble SST GPS receivers. This campaign, WEGENER/GPS-92, was initiated by the Institute for Applied Geodesy in cooperation with Delft University of Technology. The purpose was to observe the whole SLR network, for the first time, with GPS to establish a connection between the SLR and GPS reference frames. The dataset was analyzed at the Section Space Research and Technology, using the GIPSY software developed at the Jet Propulsion Laboratory and the Bernese GPS software version 3.4. In the analysis a weighted combination of the orbits provided by the IGS was used to model the motion of the GPS satellites. The results show a baseline length repeatability, which is a measure for the precision, in the order of 5 mm. More importantly, the GPS coordinate solution compares very well with the most recent SLR coordinate solution computed at Delft University of Technology. The rms differences are 3.8, 5.2 and 12.5 mm in North, East and Up, respectively, using 14 sites. It is therefore obvious that GPS will play an increasingly important role in the monitoring of the deformation and a further densification of this network. Especially since starting January 1, 1994 the IGS has become operational and combined orbits are being produced and made available with only a few week delay.