Logo Leibniz Universität Hannover
Logo: Sonderforschungsbereich geo-Q
Logo Leibniz Universität Hannover
Logo: Sonderforschungsbereich geo-Q
  • Zielgruppen
  • Suche
 

C01 - Global gravity parameter estimation

The accuracy of the global gravity field solutions, estimated from data sets of inter-satellite ranging measurements from GRACE, has increased considerably during the last decade. But there remains a difference of an order of magnitude between the error level of current solutions and the GRACE baseline accuracy. For further improvement of gravity field results, efforts are ongoing to disentangle and identify the sources of errors. A full understanding of the errors in the GRACE gravity field will then be helpful in modeling the noise and could help the gravity field solutions.

With the above mentioned aim this project focuses on -

  • The understanding of how systematic errors from the input sensors’ data and errors from other background models affect the gravity field parameter estimation by an analysis of the  post-fit range-rate residuals. The figures 01 and 02 show the systematic errors from the KBR instrument and the GRACE attitude affecting the post-fit range-rate residuals.
  • The knowledge gained from the different error sources and their possible effects from the step 1 is used in modeling the noise except just white noise reduces these errors during the parameter estimation chain (figure 03).

The similar analysis is expected to be beneficial for the GRACE FO as the mission is also based on the same principle. However, the systematics can be different which will be studied once it is launched into the orbit.

Figure 01: Systematic errors in the range-rate residuals coming the KBR instrument plotted along orbit wrt time (December 2008)
Figure 01: Systematic errors in the range-rate residuals coming the KBR instrument plotted along orbit wrt time (December 2008)
Figure 02: Power spectral density plot showing attitude errors affecting the range-rate residuals (December 2008)
Figure 02: Power spectral density plot showing attitude errors affecting the range-rate residuals (December 2008)
Figure 03: Degree variances of the solution estimated on the basis of different noise behavior assumptions and compared with the CSR, Texas solutions (December 2008)
Figure 03: Degree variances of the solution estimated on the basis of different noise behavior assumptions and compared with the CSR, Texas solutions (December 2008)

Scientists working on this project

Saniya Behzadpour
email: behzadpourife.uni-hanover.de

details

Sujata Goswami
email: goswamiife.uni-hannover.de

phone: +49 511 762-8926
details

Prof. Dr.-Ing. Torsten Mayer-Gürr
email: mayer-guerrtugraz.at

phone: +43 316 873-6359
details

Dr. Majid Naeimi
email: naeimiife.uni-hannover.de

phone: +49 511 762-5787
details

Selected Publications


Peer-Reviewed Literature

Matthias E. and Mayer-Gürr T. (2017): High precision dynamic orbit integration for spaceborne gravimetry in view of GRACE Follow-on, Advances in Space Research 60.1, 1-13.
DOI: 10.1016/j.asr.2017.04.015

Naeimi M. and Bouman J. (2017): Contribution of the GOCE gradiometer components to regional gravity solutions, Geophysical Journal International
DOI: 10.1093/gji/ggx040

Dobslaw H., Bergmann-Wolf I., Forootan E., Dahle C., Mayer-Gürr T., Kusche J. and Flechtner F. (2016): Modeling of present-day atmosphere and ocean non-tidal de-aliasing errors for future gravity mission simulations, Journal of Geodesy 90(5), 423-36
DOI: 10.1007/s00190-015-0884-3

Klinger B. and Mayer-Gürr T. (2016): The role of accelerometer data calibration within GRACE gravity field recovery: Results from ITSG-Grace2016, Advances in Space Research 58.9, 1597-1609.
DOI: 10.1016/j.asr.2016.08.007

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

Zehentner N. and Mayer-Gürr T.  (2016): Precise orbit determination based on raw GPS measurements, Journal of Geodesy 90.3, 275-286.
DOI: 10.1007/s00190-015-0872-7

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

Bandikova T. and Flury J. (2014): Improvement of the GRACE star camera data based on the revision of the combination method, Adv Space Res 54: 1818–1827
DOI: 10.1016/j.asr.2014.07.004


Non Peer-Reviewed Literature

Hamm J., Lengsfeld A., Kekec U., Pape W., Shabanloui A., Naeimi M. and Flury J. (2015): Characteristics of the GOCE orbit in the re-entry phase, ESA-SP 728, p.35-41


Books

Naeimi M. and Flury J. (Editors) (2017): Global Gravity Field Modeling from Satellite-to-Satellite Tracking Data, Lecture Notes in Earth System Sciences, Springer
DOI: 10.1007/978-3-319-49941-3
ISBN: 978-3-319-49941-3