[G07-4] GGOS observations: GNSS and co-locations

[G07-4-01] Activities of the Wettzell station in Germany

^○Daniela Thaller¹, Torben Schueler¹, Thomas Kluegel¹, Johann Eckl¹, Alexander Neidhardt², Christian Ploetz¹, Gerhard Kronschnabl¹, Hartmut Wziontek¹, Jan Kodet², Ulrich Schreiber² (1.Bundesamt fuer Kartographie und Geodaesie, Frankfurt, Germany, 2.Technische Universitaet Muenchen, Germany)

invited

The geodetic observatory in Wettzell (Germany) has a long tradition in geodetic observations for VLBI, SLR, GNSS and gravimetry, and the observatory has recently been augmented with a DORIS beacon. By this additional instrumentation, Wettzell is one of only four global geodetic observatories that are equipped with all four space geodetic techniques. Such kind of geodetic stations are of great importance for generating a stable global geodetic reference frame because co-locations of the four geodetic space techniques are crucial for consistently combining the contributions by all observing techniques.
With three VLBI telescopes – the “old" RTW with one of the longest observing history, and the new TWIN telescopes – Wettzell is a key player in the international VLBI community. The participation in diverse 24-hour sessions guarantees a stable and continuous contribution to the global reference frame. Additionally, the almost continuous participation in the Intensive sessions is the basis for a reliable and continuous determination of Universal Time with low latency, which is required for every navigation application and every satellite mission.
An important aspect at co-located sites is the determination and monitoring of the co-location network. Besides local survey campaigns in regular intervals, Wettzell is installing an inter-technique calibration target which does not only function as geometric reference for all techniques but also allows to monitor the potential differences in the timing system between the individual instruments.