CRC 1128

The Collaborative Research Centre 1128 (geo-Q)


The aim of geo-Q is to explore new frontiers and techniques for the determination of the Earth’s gravitational field and its temporal variations and monitoring the global and regional mass redistribution. Understanding the processes relevant for these changes such as the melting of the polar ice sheets, the contribution of water influx to sea level rise, and changes in the hydrological cycle allows the scientific community to better quantify and conceive climate change.

The CRC 1128 has integrated expertise from geodesy and physics in a unique constellation. geo-Q studies and develops fundamentally new sensors and measurement techniques based on quantum metrology. We investigate laser interferometric systems for ranging between test masses in orbit for satellite gravimetry, with noise levels of nanometers over large distances, and picometers locally, in configurations that allow suitable spatial and temporal sampling of gravity variations. We have succeeded in characterising major noise sources in spaceborne laser interferometry and developed tools to mitigate them.

geo-Q consists of three Research Areas which are divided into individual subprojects:

Research Area A: Frontiers of quantum sensors

Research Area B: Metrology and system modelling

Research Area C: Gravity Modelling

Raw signals are obtained from novel instruments in research area A, modelled on the system level and reduced to the gravitational contributions in  research area B, and finally combined to improved gravity models and interpreted for geodetic applications in  research area C.

Research Areas are tightly coupled in order to form a strong link from the observation at a new level of precision to a better knowledge of the gravitational field. The combined utilisation of clocks, atoms and lasers, on ground and in space, is essential to provide data across a large spectrum of length and time scales. Strong cross-fertilisation is evident as the measurement techniques on all three fields are relying on related experimental competencies, i.e., quantum optics, atom optics, lasers, stable references, and quiet environments.

The research projects are pooled in project groups, which address the observational concepts enabled by the new measurement techniques. The project groups mainly include collaboration across the boundaries of the research areas, starting from the sensor development and reaching up to gravity modelling.