Description: GravTools is new open source software for the analysis of relative gravity surveys. It facilitates the adjustment of gravity surveys based on differential and non-differential observations with weighted constraints being used for the datum definition. Further features include the estimation of vertical gravity gradients, the modelling of tidal corrections and statistical testing. GravTools was developed with a focus on user-friendliness. Hence, it comes with a graphical user interface (GUI) that allows to assess and clean the observation data, as well as visualize and compare estimation results. At Austria’s Federal Office of Metrology and Surveying (BEV) GravTools is operationally used to analyse field surveys for geoid determination and for the Austrian gravity reference network since 2022. The software was developed as a Python 3 package and uses Qt for the GUI. The object-oriented program design makes it easily expandable with new features, such as further correction models and input/output features. GravTools was published open source under the GNU GPLv3 license at https://github.com/ahellers/GravTools. In this presentation we give an overview of the features of GravTools, focusing on software design, the adjustment methods and data visualization.

Description: ETRS89 has become the common standard for harmonized horizontal coordinates in the European countries. In contrast, the national height networks are still determined by leveling with respect to different tide gauges and standards (height types, tide systems). The differences in the definitions cause height discrepancies up to a few decimeters along the borders. National geoid models are defined accordingly. Nowadays, GNSS-based height determination is widely used, which also increases the demand for geoid models as a height reference across borders. For large parts of the continent, the United European Leveling Network provides harmonized heights based on the standards of the EVRS. However, EUREF has yet to adopt a corresponding height reference surface officially. Thus, the EUREF Working Group “Unified European Height Reference” was formed by resolution in 2021 with the objective to enhance the usability of European heights for practical applications such as civil engineering, digital elevation models, etc. The main goal is to establish a European Height Reference Surface (EHRS) which is tailored to a consistent dataset of GNSS-leveling control points (EHRS_CP) referring to the latest ETRS89 and EVRS realizations. Furthermore, comprehensive information about the national integrated spatial reference systems, including heights and geoid models, shall be made available through the Information and Service System for European Coordinate Reference Systems (CRS-EU). The paper gives an overview of the rationale and current activities of the working group. Preliminary comparisons with selected gravimetric quasigeoid models provide an outlook on the increased accuracy of the new GNSS-leveling dataset.