Gravitational acceleration measurements were conducted in the Allgäu region of southern Germany by the Federal Agency for Cartography and Geodesy (BKG) in September this year. In high-altitude locations, helicopters were utilized to access the measurement points. These measurements play a crucial role in enhancing altitude determination through satellite-based methods such as GNSS.
The elevations derived from satellite navigation systems such as GPS and Galileo cannot be directly applied to many practical scenarios, as they pertain to a geometrically defined reference surface. In contrast, everyday elevation references are based on a zero-level surface known as the mean sea level geoid, which has an irregular shape influenced by the Earth’s gravity field. To make use of GNSS measurements, a transformation model is necessary to determine accurate altitudes. In the Alps, the target accuracy of one centimetre has not been consistently attained across all areas. Achieving a precise geoid model necessitates various factors, including extensive measurements of gravitational acceleration to within a few kilometres. Notably, data gaps still persist, especially along the German-Austrian border.
