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.
Goswami S., Devaraju, B., Weigelt, M. and Mayer-Gürr, T. (2018):
Analysis of GRACE range-rate residuals with focus on KBR instrument system noise, Advances in Space Research more
Goswami, S., Klinger, B., Weigelt, M. and Mayer-Gürr, T. (2018):
Analysis of attitude errors in GRACE range-rate residuals - a comparison between SCA1B and the fused attitude product (SCA1B + ACC1B), IEEE Sensor letters more
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.
Naeimi M. and Bouman J. (2017):
Contribution of the GOCE gradiometer components to regional gravity solutions, Geophysical Journal International
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
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.
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.
Zehentner N. and Mayer-Gürr T. (2016):
Precise orbit determination based on raw GPS measurements, Journal of Geodesy 90.3, 275-286.
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
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
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
Presentations, Talks and Posters
T. Kato, F. Wöske, M. List, B. Rievers and S. Goswani (2017): Satellite Geodesy Mission Preparation using Satellite Formation Flight Simulator - XHPS, In Proceedings of 68th International Astronautical Congress