The project is organized in three technical workpackages:
WP1 covers the development of novel instrumentation for large-scale dimensional measurements for geodesy. Two long-range absolute distance meters with 5 km range are developed, one based on radio frequency modulation, one on multi-wavelength interferometry. A specific focus of the development is on dealing with the measurement in air. Several inline compensation schemes are pursued; based on acoustic and spectroscopic inline thermometry, as well as dispersive intrinsic compensation. We also develop 3D measurement systems based on these ranging technologies over an extended range up to 200 m based on the multilateration principle. Finally, we also explore enhanced interpolation models for classical environmental sensor networks. Most of the work is performed within the first 18 months of the project.
WP2 is concerned with the establishment of novel reference baselines of up to 5 km with low uncertainty and their verification. To achieve the lowest uncertainties, various measures are deployed to derive reference distances. We apply the novel instrumentation developed in WP1 (and verify them thereby, too). We also deploy an advanced analysis approach for GNSS-based distance metrology (GBDM+), and established standard methods. We also perform two highly interesting case studies: we investigate our novel methods and instrumentation at the CERN overground surveillance network, and compare SLR distance to reference distances obtained by the Arpent system developed in WP1 at the Observatoire de la Cote d'Azur, France.
Because of their critical role for the International Terrestrial Reference Frame, local tie metrology is certainly one of the most advanced surveying discipline. In joint effort, we try to contribute to further advancement, tackling the problem from different directions. All novel methods and instrumentation are jointly investigated, and their benefit for the complex measurement analysis and for the final product critically assessed.