mtr, swarm e2e study, nov 11, 2003, dsri copenhagen, nio #1 7-sep-15 swarm end-to-end mission...

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


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


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


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)


Outline of Task 2

(red boxes are part of Task 3)


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


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


Data Products: Overview


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


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


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


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

mtr, swarm e2e study, nov 11, 2003, dsri copenhagen, nio #1 7-sep-15 swarm end-to-end mission...

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