Density and Winds Inferred from GOCE Accelerometer ( thrusters ) Data Sean Bruinsma
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Density and Winds Inferred from GOCE Accelerometer (thrusters) Data
Sean BruinsmaCNES, Toulouse
Eelco DoornbosDelft University of Technology
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ESA contract No. 4000102847/11/NL/EL with TU Delft
Consortium: TU Delft - Management and productionCNES - Product evaluationHTG - Non-gravitational force modeling
Project information
http://thermosphere.tudelft.nl/goceplustheme3/ (nb: register first)
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Launch: 17 march 2009 (Plesetsk)Mission objectives:Determine geoid with an accuracy of 2 cm and gravity anomalies with an accuracy of 1-2 mGal (1-2 10-5 m/s2) at a resolution of 100 km (degree 200)
Mission orbit:Sun-synchronous (i=96.5°), dawn/dusk, 255 km altitude
Payload:Gradiometer (accelerometers), GPS receiver, laser retroreflector
Drag control:Ion thrusters commanded in closed-loop
GOCE: ESA’s first Earth Explorer
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GOCE: ESA’s first Earth Explorer
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GOCE mission in perspective
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GOCE mission in perspective
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GOCE mission in perspective
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GOCE: drag and solar radiation
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GOCE: drag and solar radiation
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GOCE natural decay & drag-freeNatural decay (about 3 months, not shown) followed by drag-free flight starting 13 September 2009 at the mission altitude of 254.9 km(NB: the figure shows mean spherical altitude)
Density inferred from accelerometer data
Density inferred from thrusters+accelerometer data
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GOCE thrusters data
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GOCE thrusters data
Thrust < 3mN: noise(red line=3-point average
Thruster data sampling: 8 s
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Preliminary GOCE densities
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Preliminary GOCE densities
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Preliminary GOCE densities
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GOCE densities
To do:• Implement satellite model• Combine thrusters and accelerometer data• Compute densities and winds• Validate products
Poster in session SA10 at the AGU Fall Meeting