Permanent monitoring of the reference point at the 20m radio telescope Wettzell

To achieve the aims of the VLBI2010 agenda and of the Global Geodetic Observing System (GGOS) an automated monitoring of the reference points of different geodetic space techniques, such as Very Long Baseline Interferometry (VLBI), is desirable. The resulting permanent monitoring of the local-tie vectors at co-location stations are essential to obtain the sub-millimeter level in the combinations. For this reason a monitoring system was installed by the Geodetic institute of the University of Karlsruhe (GIK) to observe the 20m radio telescope for VLBI at the Geodetic Observatory Wettzell from May to August.
A specially developed software from the Geodetic Institute of the university collected data from automated total station measurements, meteorological sensors, and sensors in the telescope monument (e.g., Invar cable data). A real-time visualization directly offered a live view of the measurements during the regular observation operations. Additional scintillometer measurements allowed refraction corrections during the post-processing. This project is one of the first feasibility studies aimed at determining significant deformations of the VLBI antenna due to, for instance, changes in temperature.