Geoid+ - Improved Austrian Geoid Solution combining terrestrial and satellite Gravity Data

The main objective of the present project proposal GEOID+ is the computation of an improved geoid model for the Austrian territory, as a combined solution from terrestrial gravity field data (gravity anomalies, deflections of the vertical, direct geoid observations being the difference between geometrical heights obtained by high-precision GPS observations and orthometric heights by spirit levelling), and satellite-related data from the dedicated gravity field missions GRACE and GOCE, which shall stabilize the solution in the long to medium wavelength domain. Compared to the currently available Austrian geoid model, which was computed in the frame of the ASAP Phase 3 project The Austrian Geoid 2007 (GEOnAUT), several enhancements related to new, validated and more accurate terrestrial input data, the incorporation of a global gravity field model based on GOCE data, methodological improvements in the computation process, as well as the opportunity of an independent validation on the basis of the European geoid model shall be performed. The precise knowledge of the geoid, representing a physical reference surface and reference level for height systems, is required and applied in civil engineering projects, telecommunication and telematics applications, as well as numerous geoscientific applications. The height determination by the combination of GPS observations and geoid information can replace the elaborate and expensive work of spirit levelling. Also the unification and validation of the national levelling network takes benefit from a high-precision geoid. Nowadays, the availability of high-accuracy global satellite gravity models enables to make the local geoid model consistent, also concerning the absolute level, with a global reference frame. The availability of highaccuracy global gravity data from satellite missions produced the need to upgrade the formerly used standard processing strategies. Correspondingly, in the frame of this project sophisticated and innovative methods of numerical and computational mathematics shall be investigated and applied to meet this goal.