Automated IVS Reference Point Monitoring - First Experience from the Onsala Space Observatory

Other conference contribution, 2013

The realization of the International Terrestrial Reference Frame (ITRF) builds upon a combination of results derived from several geodetic space techniques, such as Very Long Baseline Interferometry (VLBI), Satellite and Lunar Laser Ranging (SLR and LLR) or Global Navigation Satellite Systems (GNSS). To combine the different techniques and their results in a meaningful way, co-location sites are important where equipment for several techniques is located reasonably close to each other. The relative geometries (local tie vectors) between the geometric reference points of the different techniques can be derived by terrestrial survey at these co-location sites. Within the Global Geodetic Observing System (GGOS) the requirements in terms of e.g. accuracy and frequency of local survey campaigns have been increased to guarantee that the local tie vectors reach an utmost level of global accuracy. In response to this request we developed a concept to achieve automated and continuous monitoring of radio telescope reference points. This concept was realized and tested in 2012 at the Onsala Space Observatory where an automated monitoring system was installed for a continual determination of the reference point of the 20 m radio telescope. The results confirm that uncertainties on the sub-mm level can be achieved with this approach.