18SIB01 GeoMetre

Geodetic reference frames form the backbone of all georeferencing services, providing the geospatial reference for global observations as sea level monitoring or Earth crustal movements. To strengthen the complex traceability chain, this project focussed on two issues: the creation of new long-distances references for the Earth-bound verification of space-geodetic methods like Satellite Laser Ranging (SLR) or Global Navigation Satellite Systems (GNSS) and on the measurement of the local tie vectors, the geometric connection of reference points of co-located space-geodetic telescopes. For this, the project developed specifically tailored instrumentation, like, e.g., new range meters capable to measure up to 5 km in air with sub-millimetric uncertainty, a metrologically-sound approach to GNSS-based distance measurement, or a 3D multilateration system for an outdoor working volume of 50 m which reduces the measurement uncertainty compared to state-of-the-art systems by a factor of 3. Using these systems and methods, novel reference standards like a new 5000 m reference network were established, and successful case studies for GNSS and SLR verification performed. In a unique effort, the local tie vector measurement was tackled from multplie angles at two European space-geodetic co-location sites. The novel measurement systems, but also novel measurement and analysis approaches showed their potential to push the accuracy limits further, below the targeted uncertainty limit of 1 mm.