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B07 - System studies for an optical gradiometer mission

Figure 01: Scheme of one axis of the optical gradiometer concept
Figure 01: Scheme of one axis of the optical gradiometer concept
Figure 02: Noise level requirement for the optical gradiometer and comparison to GOCE
Figure 02: Noise level requirement for the optical gradiometer and comparison to GOCE

In the wake of the far-reaching benefits of the gravity missions GRACE and GOCE, there is a strong demand for sustaining a global and continuous mapping of the Earth‘s gravitational field. In project B07, we study to what extent gravitational gradiometry could be a good candidate for future missions in the light of current developments in sensor physics. This has led us to study new concepts of inertial sensors based on laser interferometry and to a lower extent cold atom interferometry. The work carried out includes analytical studies and simulations to

  • quantify the requirements of the end-users in terms of precision and resolution of the recovered gravity field model
  • derive the corresponding requirements at the level of the different sensors, e.g., gradiometer (figure 02), accelerometers, attitude determination system, etc.
  • design, model and characterize gradiometer concepts that can meet these requirements and
  • test and evaluate such concepts based on end-to-end simulations.

The gradiometer concept consisting of pairs of electrostatic accelerometers with a laser interferometry read-out (figure 01) seems particularly promising. The resolution and noise level can indeed be significantly improved compared to the GOCE gradiometer and the recovery of tiny temporal variations of the gravity field becomes possible. While a parallel project, A07, aims to develop the optical read-out system for such a gradiometer, we focus on the system-level implications, e.g., the optimization of the physical parameters of the accelerometers, the trade-off between the gradiometer dynamic range and the spacecraft dynamics, the processing of raw data and their calibration and eventually the evaluation of the performance of the sensor concept in the framework of realistic simulations.

So far, we modeled the full gradiometry measurement chain, partly with simplified assumptions on calibration and drag-free control. A sensitivity level of 10-4E/√Hz for the gradiometer seems to be feasible.

Scientists working on this project

Karim Douch
email: douchife.uni-hannover.de

phone: +49 511 762-5697
details

Brigitte Kaune
email: brigitte.kauneaei.mpg.de

phone: +49 511 762-17279
details

Dr. Akbar Shabanloui
email: shabanlouiife.uni-hannover.de

phone: +49 511 762-5149
details

Selected Publications


Peer-Reviewed Literature

Shabanloui A. and Müller J. (2016): Mass variations in the Siberian permafrost region based on new GRACE results and auxiliary modeling, International Association of Geodesy Symposia, pp. 1–8.
DOI: 10.1007/1345_2015_186

Naeimi M., Flury J. and Brieden P. (2015): On the regularization of regional gravity field solutions in spherical radial base functions, Geophys J Int 202(2):1041-1053
DOI: 10.1093/gji/ggv210



Presentations, Talks and Posters

Douch K., Müller J., Heinzel G., Brieden P. and Shabanloui A. (2016): Performance assessment of an optical gradiometer for future gravitational missions, 2016 European Space Agency Living Planet Symposium, Prague, Czech Republic, 9 - 13 May, 2016

Douch K., Wu H., Müller J., Shabanloui A., Brieden P. and Heinzel G. (2016): A first performance assessment of two new concepts of satellite gravitational gradiometers, International Symposium on Gravity, Geoid and Height Systems, Thessaloniki, Greece, 19 - 23 September, 2016

Douch K., Müller J., Brieden P., Shabanloui A. (2015): Study of an optical gradiometer for future satellite gravitational missions, Geodätische Woche / INTERGEO 2015, Stuttgart, Germany

Douch K., Müller J., Heinzel G., Brieden P., Shabanloui A. and Wu H. (2015): System studies for an optical gradiometer mission, geo-Q Kickoff Meeting, Bremen

Douch K., Panet I., Foulon B., Christophe B. (2015): Feasibility and performance assessment of a new gravitational gradiometer for airborne surveys, 26th General Assembly of the International Union of Geodesy and Geophysics, Prague, Czech Republic, 22 June - 02 July, 2015 more