mtr, swarm e2e study, nov 11, 2003, dsri copenhagen, nio #1 7-sep-15 swarm end-to-end mission...
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MTR, swarm E2E study, Nov 11, 2003, DSRI Copenhagen, nio #1 Apr 21, 2023
swarm End-To-End Mission Performance StudyMid Term Review
The swarm E2E Consortium
DSRI:Eigil Friis ChristensenFlemming Hansen Nils OlsenPer Lundahl ThomsenSusanne Vennerstrøm
IPGP:Gauthier HulotMioara Mandea
BGS:Vincent LesurSusan MacmillanAlan Thomson
GFZ:Monika KorteHermann LührStefan MausChristoph ReigberPatricia RitterMartin Rother
GSFC:Michael PuruckerTerence Sabaka
IUEM:Pascal Tarits
G FZ Potsda m IPG P IU EM B G S G SFC
D SR IStudy C oordina tion
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swarm Mid Term Review
Draft Agenda
• Achieved Milestones
• Presentation of the results achieved in Task 2– Example 1: Lithospheric Field Recovery (HL)– Example 2: Comprehensive Inversion (TJS)
• How to proceed in Task 3
• General discussion
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Achieved Milestones
Task 1:• Development, implementation, test and delivery of documented software
modules to industry– calculation of the magnetic field and its variations for a given position and time
• Design of a reference model (swarm_02a_03) up to Spherical Harmonic Degree n=120
Task 2:• Design, implementation and test of modules to produce synthetic data
– orbit generator– magnetic field generator– electric field generator– auxiliary data
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Achieved Milestones (cont.)
Task 2:• Development of Testplan
– test quantities and procedure
• Successful closed-loop simulationrecovery of field using data that only contain contributions from those fields
– Example 1: lithospheric field (cf. presentation by Hermann Lühr)– Example 2: comprehensive inversion (cf. presentation by Terence J. Sabaka)
• Successful ”full inversion”noise-free data, but containing all source contributions (and thus unmodeled external signals)
– Recovery of lithospheric field at least up to n=85 (cf. HL+TJS)– Recovery of high-degree secular variation at least up to n=19 (cf. TJS)
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Outline of Task 2
(red boxes are part of Task 3)
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Orbit Design Initial Constellation # 1
• Two pairs of satellites450 and 550 km initial altitude86.0° and 85.4° inclination
• lower satellites are close together separation a few hundred km
• upper satellites are at antipodal position 180° separation
• Different inclinations yields different drift rates0.44 min/day differential drift rate corresponding to 90° separation after 27 months
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Magnetic Field Generation
From the Comprehensive Model CM4 (Sabaka et al)
High-degree crustal field (n up to 120) and secular variation (n up to 20) from synthetic model
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Data Products: Overview
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Test Plan
• Closed-loop-simulation: Test of the forward and inversion approaches using noise-free data
– using data that only contain source fields for which we invert for
• Focus on field contributions that are main swarm objectives– Core field and secular variation– Lithospheric field
• Test quantities: Difference between recovered and original model– Power spectrum of the model SH coefficients
– Degree correlation n of coefficients
– Sensitivity matrix
– Global Maps (e.g., of Br) of the model difference
• Results:– successful recovery of the original model using clean and noise-free data
• Definition: noise-free data data without additional S/C and payload noise clean data data that only contain source contributions that
is inverted for
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Various Approaches for Field Recovery
• Comprehensive Inversion
• Core Surface Field and Secular Variation - Method 1
• Earth Surface Main Field and Secular Variation
• Lithospheric Field Recovery - Method 1
• Lithospheric Field Recovery - Method 2
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Example of Study Result
Recovery of lithospheric field ...
... and of high-degree secular variation
using data from 4 swarm satellites and 88 observatories
degree correlation n > 0.9
Achieved by Comprehensive Inversion; details will be given by T.J. Sabaka
original modelrecovered model
difference
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How to proceed in Task 3
• Adjustment of Forward Scheme– perform experiments with small-scale contributions from ionospheric and toroidal
fields– perform experiments with large-scale magnetospheric field (e.g. non-periodic
variations of coefficients with n>1)– induced field due to 3D conductivity (oceans, sediments and mantle)
• Inclusion of S/C and Payload Noise
• Other Constellation/Combination of Satellites– additional ”constellation #1” satellites
» inversion using data from up to 4 out of, e.g., 6 satellites
– new constellation: #2