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Bavarian Commission for International Geodesy
Since 1868, scientists of the "Bayerische Kommission für die Internationale Erdmessung" are dealing with long term Earth observations and geodetic methodology. "Internationale Erdmessung" refers to an early international geodetic association, to which our Commission represented the affiliate of the Bavarian state. The successor of this international organisation is now called "International Association of Geodesy" while the name of our Commission was kept.
Within the work area positioning, coordinates of selected reference markers are determined by continuous observations to the satellite-based GPS system at high precision. The resulting 3D coordinates serve for the definition of a geodetic reference system and also for the derivation of temporal changes to an accuracy of milimetres per annum.
The Commission also acts as a local analysis centre in the framework of international cooperation for the definition of a European positioning reference network (EUREF). We are also involved in studies of recent crustal movements on Iceland.
Within the ALPS-GPSQUAKENET research project – co-funded by the EU – the Commission is also engaged in establishing a geodetic network in the Alps (see figure). The network serves for basic studies of movements induced by plate tectonics including earthquake mechanisms in the Alpine-Mediterranean region.
Data on the Earth's gravity field also contribute fundamentaly as basis to geodesy and other geosciences. In this work area, a gravity reference network including 1600 reference stations in 17 countries has emerged. Evaluation of a large number of existing observations conduces to homogeneous standards throughout Europe.
Methods and observation techniques for the detailed reconnaissance of the Earth's gravity field from an aircraft are being developed in another project. Gravity is recovered by taking the difference of total acceleration observations and inertial accelerations of the aircraft. The challenge lies in the high spatial resolution while simultaneously facilitating the procedures. A sensor – including four precision accelerometers and three fibre optical gyroscopes for orientation – samples the total acceleration vector to a millionth of Earth's gravity 100 times per second. Fast GPS receivers provide the position of the aircraft at each metre of the flight trajectory with a precision of a few millimetres and also the orientation angles. At the current status of this patented concept, 12 GPS receivers are connected to 9 antennae (see figure).
The Geodetic Alpine Integrated Network (GAIN) for monitoring crustal deformation in the Alps