Main task  Exploitation of science data collected by space-geodetic techniques Main research topics 1.Dynamic orbit determination/prediction  Trajectories from SLR and radio science measurements 2.Gravity field  Static and time-variable gravity field recovery  Mass variation from time-variable gravity 3.Satellite accelerometry  Atmosphere evolution studies Refereed publications (since Jan 2013)  Total: 7 (first author: 6) Educational activities (since Jan 2013)  PhD thesis: 1, Master thesis: 1  Teaching at Graz University of Technology Gravity Field IWF/ÖAW1

Lead: Oliver Baur Members  Staff: S. Krauss, K. Yamamoto  Students: PhD: A. Maier, H. Wirnsberger Master: B. Klinger, A. Purkhauser, S. Reimond Cooperation within IWF  SLR Group (Kirchner et al.): SLR orbit determination/prediction  Atmosphere-Plasma (Lammer et al.): Atmosphere response to solar activity Key external collaboration Australia: Curtin University of Technology; Austria: TU Graz, KFU Graz; Czech Republic: University of West Bohemia; Germany: University of Stuttgart, TU Munich; Greece: TU Crete; Luxembourg: University of Luxembourg; Switzerland: University of Bern; The Netherlands: TU Delft Who are we? IWF/ÖAW2

3 Orbit Determination - SLR Accuracy of ENVISAT orbit depending on observation technique Exemplary availability of SLR observations to ENVISAT (01 Jul to 18 Aug 2013) Geodetic satellites  Participation in the international GOCO project  Dynamic flattening of the Earth can best be recovered by SLR  Analysis of laser measurements to six satellites  Results accessible via ILRS website Space debris  Sparse data; parameterization challenging  SLR-based orbit determination and prediction superior to radar (TLEs)  “Traditional“ ranging successfully augmented by bi-static measurements  Orbit predictions accessible via ILRS website please visit poster TLE SLR SLR and bi-static

LRO  Tracked by optical (laser ranges) and radiometric (Doppler shifts, ranges) techniques  “Pilot endeavor“ at IWF for orbit determination from radio science  Modeling and parameterization challenging  Very promising results achieved IWF/ÖAW 4 Inter-satellite and ground-based tracking of the GRAIL spacecraft (credits: NASA) Differences between IWF (Doppler-only) and NASA orbits (Doppler, ranges) GRAIL  First experiences in the framework of simulation studies  Satellites tracked by the Deep Space Network  Data freely available via PDS  Software development started (as alternative to Geodyn) Orbit Determination - Doppler please visit poster

GOCE  Tuning gravity field recovery from GPS-tracked satellites  Motivated by the potentially more pronounced role of orbit analysis  Several methods have been developed in the last decade  Large-scale study: comparison of results from different approaches IWF/ÖAW 5 Static Gravity Field GrazLGM200a model in terms of free-air gravity anomalies Degree-error RMS values of recovered spherical harmonic coefficients GRAIL  Relevance for geophysics  Transfer of experience from GRACE  Analysis of Ka-band data from the nominal science mission phase  First lunar gravity field model (GrazLGM200a) released  Cooperation with TU Graz

GRACE  Detection of mass changes (secular, periodic) on the Earth’s surface  Important source of information for climate research (cf. IPCC-AR5)  Continental balance, impact on sea level  Outlived nominal lifetime by far (follow-on mission approved) IWF/ÖAW 6 Spatial mass variation patterns from time-variable gravity GRACE-derived secular mass change; strongest signals over Greenland & Antarctica CHAMP/Swarm  Motivated by the likely gap between GRACE and GRACE-FO  Orbit analysis (cf. GOCE, SLR)  CHAMP as case study for Swarm (promising bridging candidate)  Potential for glaciology/hydrology has been demonstrated  Swarm tracking data supposed to be released in mid-2014 Time-Variable Gravity Field GRACE CHAMP

Atmosphere IWF/ÖAW7 Thermospheric density variation  Determination of neutral densities from GRACE accelerations  Response of the Earth’s upper atmosphere to extreme solar events  Proxy for the young Sun  ICMEs/solar flares  Comparisons with empirical and theoretical thermosphere models Atmospheric neutral density from GRACECorrelation diagram ICME characterization  Cooperation with KFU Graz  Speed, magnetic field (magnitude, orientation)  Regular measurements at L1 (NASA Wind, ACE)  Relation between geomagnetic disturbances and density variation

Dynamic orbit determination  SLR: incorporation of multi-static (and pointing angle) measurements  Doppler: trajectories of planetary orbiters  Software development Gravity field  GRAIL and Swarm data processing  Inference of mass variation from gravity (Swarm, GRACE, GRACE-FO)  Gravity field determination of irregularly shaped bodies (e.g., comets)  Combination of gravity with altimetry-based topography (geophysical studies) Depending on funds (project proposals)  Atmosphere: relations with ICMEs  Austrian contribution to GGOS IWF/ÖAW8 Future Plans: GGOS & the three pillars of geodesy SWARM configuration (credits: ESA)

IWF/ÖAW9 Thank you

Dr. Oliver Baur Career Summary Research Associate, Institute of Geodesy, University of Stuttgart, Germany 2005Visiting Scientist, Department of Earth Observation and Space Systems, Delft University of Technology, Netherlands 2007Research Associate, Department of Spatial Sciences, Curtin University of Technology, Perth, Australia Assistant Professor, Institute of Geodesy, University of Stuttgart, Germany 2010Visiting Scientist, Department of Spatial Sciences, Curtin University of Technology since 2010Group Leader, Institut für Weltraumforschung, ÖAW, Austria since 2011Teaching at Institute of Theoretical Geodesy and Satellite Geodesy, Graz University of Technology, Austria Publications 38 Articles (First Author: 22, Refereed: 22) Research Interests Terrestrial and planetary satellite geodesy International Scientific Activities since 2011Member, IAG Inter-Commission Study Group Applicability of current GRACE solution strategies to the next generation of inter-satellite range observations since 2011Member, Steering Committee of IAG Commission 2 Gravity Field since 2011Chair, IAG Joint Project Geodetic Planetology