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Research group | Global Geodetic Observing System (GGOS)

Galileo test satellite GIOVE-B. Image: European Space Agency ESA

GGOS is the central global initiative of international Geodesy aiming at determination of the geodetic quantities gravity field, rotation and figure of the earth with consistent accuracy at the 10-9 level, corresponding to centimetre accuracy at the earth’s surface. This is in order to monitor the complex processes of the earth system.

The research group addresses central components in this field. It analyses Lunar Laser Ranging data obtained over 40 years to investigate viable modifications of Einstein’s theory, for example such as the test of the strong equivalence principle or temporal variation of the gravitational constant. For this, the complete modeling of the Earth-Moon system is refined.

The workgroup contributes substantiallly to refining GNSS (Global Navigation Satellite System) positioning by integrating QUEST technology. By using high-precision atomic oscillators such as hydrogen masers in combination with clock modeling, many of the present limitations are overcome so that the millimetre accuracy is achieved.

Ever larger data sets and the large number of solve-for parameters in high precision geodesy, for example about 100.000 for moedelling the earth’s gravity, require suitable analysis tools which are developed in this research group. In addition, extensive research on fast solvers is performed to deal with the highly ill-conditioned matrices arising in gravity field computations.

Novel QUEST technology is being investigated in close cooperation with Task Group “Next Generation Gravity Field Missions" and research group “Precision Geodesy on Earth and in Space”, in respect of its application tonext generation gravity field missions.