Finished Research Projects – Institute of Geodesy

Disentangling gravitational signals and errors in global gravity field parameter estimation from satellite observations (SFB 1128, C01)

Range-rate residuals from the estimation of global gravity field parameters from GRACE satellite-to-satellite tracking reveal a range of systematic effects that limit the accuracy of the estimated parameters. The project investigated the characteristics of time series of range-rate residuals. It addressed how drops in the K-band ranging signal-to-noise ratio at specific inter-satellite Doppler frequencies propagate to anomalies in range-rate residuals, as well as anomalies during penumbra transitions. A part of the project at TU Graz, in the group of Prof. Mayer-Gürr, studied options to use wavelet parameters in the SST gravity field parameter estimation.

Led by: Prof. Jakob Flury

Team: M.Sc. Saniya Behzadpour

Year: 2014

Funding: DFG

Duration: 2014-2018

Highly physical penumbra solar radiation pressure modeling with atmospheric effects

During penumbra transitions of an Earth orbiter, the solar radiation hitting the satellite is strongly influenced by refraction and absorption of light rays grazing the Earth’s atmosphere. The project implemented solar radiation pressure modeling including these effects. Model results were tested by comparing with measurements of the accelerometers of the GRACE low Earth orbiters.

Led by: Prof. Jakob Flury, Tamara Bandikova

Team: Robbie Robertson (Virginia Tech, Blacksburg, VA)

Year: 2010

Funding: RISE/QUEST

Duration: 2010

In-Orbit System Analysis of the Gravity Recovery and Climate Experiment (GRACE) Mission

Precise determination and control of satellite attitude plays a key role for satellite geodesy in general, and for Satellite-to-Satellite Tracking in particular. The project provided the first in-depth characterization of GRACE pointing biases and pointing variations. Investigations addressed star camera inter-boresight angle variations, the weighted camera sensor head combination, as well as error propagation to inter-satellite ranging and accelerometer observations. Results led to significant improvements in the operational GRACE data processing.

Led by: Prof. Jakob Flury

Team: Tamara Bandikova

Year: 2009

Funding: Exzellenzcluster QUEST

Duration: 2009-2015