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Logo: Sonderforschungsbereich geo-Q
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C02 - Relativistic effects in satellite constellations

For space based geodesy the relative orbits of satellites have to be tracked with very high precision. In the next years, the necessary experimental capabilities will increase dramatically by the use of laser technology and high precision space clock projects.

  • Inter-satellite laser ranging enables to measure the distance between two or more spacecraft to an accuracy of up to 10 nm. At this level general relativistic effects in the determination of the orbit have to be taken into account. This also includes the relativistic effects of the multipoles of the gravitating body on the orbit.
  • On this level of accuracy also general relativistic effects on the signal propagation have to be considered.
  • With the development of ACES, stable clocks in space will be established with inaccuracies of only a few parts in 1016. Such accurate time measurements can only be interpreted correctly if the full framework of general relativistic effects is taken into account.

As a consequence, at the present technological level for spaced based geodesy it has to be critically analyzed whether the usual post-Newtonian approximations are sufficient to fully exploit the experimental capabilities. The huge technological improvements in the next years and decades can only lead to equally huge improvements in geodesy and related science if a consistent fully general relativistic formulation of geodetic quantities and observables is provided. On the one hand this is needed to judge the accuracy and to derive better relativistic approximations, and on the other hand to provide a complete picture of relativistic effects to be considered in future geodesy missions. Therefore, the crucial aim is to provide fully relativistic descriptions

  • of clocks in space, satellite orbits, and signal propagation (to S/C and ground stations) to an accuracy which allows to fully exploit the experimental capabilities, in particular
  • of the motion of satellites in the gravitational field of the Earth taking into account its relativistic mass multipole moments. Related to this is the definition of general relativistic analogies of concepts commonly used in geodesy, e.g. the geoid and gravity anomalies.

In addition, we will suggest new experimental and theoretical concepts for geodesy in space, which will significantly improve the evaluation and interpretation of gravity measurements and which will provide new approaches for future geodesy missions. This comprises

  • the development of an improved semi-analytical orbital theory, based on the Lie series approach, focusing on relativistic effects, and
  • the investigation of new concepts which are more powerful and effective for gravity measurements based on swarms of satellites.

As an add-on we would like to analyze whether these high precision measurements in the gravitational field of the Earth can be used for improved tests of Special and General Relativity, e.g. for an improved test of the Lense-Thirring precession or a first measurement of the gravitomagnetic clock effect.  

Scientists working on this project

Dr. Liliane Biskupek
email: biskupekife.uni-hannover.de

phone: +49 511 762-5785
details

PD Dr. Volker Perlick
email: volker.perlickzarm.uni-bremen.de

phone: +49 421 218-57933
details

Dennis Philipp
email: dennis.philippzarm.uni-bremen.de

phone: +49 421 218-57950
details

Selected Publications


Peer-Reviewed Literature

Philipp D., Pützfeld D. and Lämmerzahl C. (2016): On the applicability of the geodesic deviation equation in General Relativity (submitted)
arXiv: 1604.07173

Hackmann E. and Lämmerzahl C. (2014): Generalized gravitomagnetic clock effect, Phys. Rev. D, 90:044059
DOI: 10.1103/PhysRevD.90.044059
arXiv: 1406.6232


Non Peer-Reviewed Literature

Philipp D. and Pützfeld D. (2015): On geodesic deviation in static spherically symmetric situations, April 2016, Proceedings of the 14th Marcel Grossmann Meeting, July 12-18, 2015, Rome, Italy

Philipp D. et al. (2015): Metrology for Aerospace (MetroAeroSpace), 2015 IEEE, 198


Presentations, Talks and Posters

Biskupek L. and Mai E. (2016): Numerical integration of the Schwarzschild problem using Lie series for the calculation of satellite orbits, 609. WE-Heraeus-Seminar: Relativistic Geodesy: Foundations and Applications, Bad Honnef, Germany, 14 - 18 March, 2016

Biskupek L. and Mai E. (2015): Numerical integration of the Schwarzschild problem using Lie series for the calculation of satellite orbits, 26th IUGG General Assembly, Prague, Czech Republic, 22 June – 02 July, 2015 more

Biskupek L. and Mai E. (2015): Numerische Integration des Schwarzschild Problems mit Hilfe von Lie-Reihen, Geodätische Woche 2015, Stuttgart, Germany, 15 September, 2015 more