GOCE-GRAND-2 Project Overview and Status of the GOCE Mission

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1 GOCE-GRAND-2 Project Overview and Status of the GOCE Mission Reiner Rummel, Thomas Gruber & Jakob Flury Institut für Astronomische und Physikalische Geodäsie Technische Universität München Geotechnologien Status-Seminar Observation System Earth from Space Bonn 18. und 19. September 2006

2 Contents: GOCE Characteristics and Mission Status objectives and structure of GOCE-GRAND-2 matrix structure of GOCE-GRAND-2 embedding of GOCE-GRAND-2 in GOCE mission activities

3 GOCE Gravity Mission Acronym: Gravity and Steady-State Ocean Circulation Explorer Mission Objectives: Geoid std.dev. 1cm Gravity (anomalies) std. dev. 1mGal, Spatial resolution: 80 km (Lmax= 200) Launch: September 2007

4 Users (Science and Application) solid Earth physics physical oceanography and climate research geodesy sea level research

5 10 8 half wavelength [km] GMs Kaula GOCE: maximum resolution (s= 80 km) SST hl Degree RMS SGG SST ll GRACE: maximum precision (geoid < μm) spherical harmonic degree

6 Sensor Measurements Gravity gradients Г xx, Г yy, Г zz in instrument system and inside MBW (measurement bandwidth) 3-axis gravity gradiometer Angular accelerations (highly accurate around y-axis, less accurate around x, z axes) Common mode accelerations Star sensors GPS receiver Drag control with 2 ion thrusters Angular control with magnetic torquers Orbit altitude maintenance Internal calibration of gradiometer (and quadratic factors) High rate and high precision inertial orientation Orbit trajectory with cm-precision Based on common mode accelerations from gradiometer data Based on angular rates from star sensors and gradiometer Based on GPS orbit Random shaking with cold gas thrusters (and random pulses)

7 Status of GOCE development newly developed GPS receiver laser tracking

8 Status of GOCE development Attitude and Drag-free control

9 accelerometers, 1-axis gradiometer 3-axis gradiometer Status of GOCE development

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13 Uni Hamburg Uni Hannover GFZ Potsdam Uni Bonn BKG Frankfurt U Stuttgart TU München

14 GOCE Gravity Field Processing Adaptive Refinements in GOCE Gravity Field Modelling and Implementation of the Operational Software pcgma GOCE Gravity Field Modelling Further Methodology Investigation on Alternative Estimation Procedures SST and SGG Gravity Analysis Realization of the Actual GOCE Sensor Concept The Polar Gap Problem Solution Strategies and Influence on the GOCE/GRACE Combination Solution Regionally Adapted Global Gravity Field Determination by SGG and SST Data Results of GOCE-GRAND I Combined Gravity Modelling Calibration and Validation High Resolution Global Combination Solutions Quality Assessment of GOCE Gradients Gravity Field Validation with Terrestrial Geoid and Gravity Anomalies Regional Validation and Combination Experiment Gravity Field Validation Using Ocean Data and Ocean Dynamics Integral Motion and its Role for Consistency Validation of Force Functions and Orbits Other Geotechnology II Projects: Optimized GRACE Level-1 and Level-2 Products More Precise and Faster Gravity Field Products (CHAMP,GRACE) IAPG GFZ BKG & IFE IFM ITG GIS IFE

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17 10 8 half wavelength [km] GMs Kaula GOCE: maximum resolution (s= 80 km) SST hl Degree RMS SGG SST ll GRACE: maximum precision (geoid < μm) spherical harmonic degree

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19 Calibration and Validation GOCE CAL/VAL data sets long wavelength short long wavelength short spectral representation spectral representation spatial represention global regional local spatial represention global regional local

20 Regional Validation and Combination Experiment Observations of vertical deflections (courtesy IFE Hannover)

21 Klassische Bilanzgleichungen Impulsbilanz Drehimpulsbilanz Energiebilanz M R K = 0 M R K = 0 M R K = 0 vektorielle Multiplikation mit R skalare. Multiplikation mit R MR R R K = 0 M R R K R = 0 Zeitintegration Zeitintegration Zeitintegration t MR Kdt = P t 0 0 t MR R R Kdt = L t MR 2 2 t K R dt = E t 0 Impuls = Anfangsimpuls + integrierte Kraft Drehimpuls = Anfangsdrehimpuls + integriertes Drehmoment Energie = kinetische Energie - integrierte Arbeit

22 GOCE-GRAND-2 Working Groups GOCE Standards System Transformations; Geometrical Models; Dynamical Models. GOCE and Surface Data GOCE and Applications Combination & Validation; Corrections to be applied; Data Weighting; Aliasing & Filtering Techniques. Identification of Needs; Zero Potential; Derived Gravity Field Quantities on Ellipsoid or Earth Surface.

23 GOCE ground segment level 0 CMF PDS ILRS IGS level 1a/1b ECMWF GOCE Cal/Val Team HPF level 2 GOCE User Toolbox GOCE Application Studies GOCE Users level 3

24 GOCE ground segment level 0 GOCE Cal/Val Team CMF PDS HPF GOCE-GRAND-2 GOCE User Toolbox ILRS IGS ECMWF level 1a/1b level 2 GOCE Application Studies GOCE Users level 3

25 The GRAND Picture Embedding of GOCE-GRAND-2 Participation in ESA GOCE processing (ESA contracts): PDS, HPF, CMF, CAL/VAL, GUTs, other studies Connection to GT Themes 2 of Observation of Earth System from Space Participation in DFG Priority Programme 1257 Mass Transport and Mass Distribution in System Earth Involvement in IAG Pilot Project: GGOS (will belong to IGOS and GEO)

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