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Transcript of Direction - Conférence 1. Latest developments in MEO radiation belt Models D.Lazaro, A.Sicard-Piet,...
Latest developments in MEO radiation
belt Models
D.Lazaro, A.Sicard-Piet, S.Bourdarie
ONERA/DESP, Toulouse, France
Session 2: Global Navigation Satellite Systems
Fifth European Space Weather Week: 17-21 November 2008, Brussels, Belgium
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• Context:• Rising number of satellites in the MEO environment• Heart of the highly dynamic electron radiation belt• Large radiation doses and significant internal charging hazards• NASA model AE8 universally used but presents deficiencies
• MEO radiation belt models efforts• New empirical & physical models• Temporal, spatial & spectral variations• Fluxes evaluation @ GNSS orbit
ONERA MEO-V2 model ESA project "Energetic Electron Environment Models for MEO"
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• ONERA MEO-V2 model:
Data set:
• From 1990 to present: • 4 GPS NavStar with BDDII:
• NS18• NS 24• NS 28• NS 33
• 1 GPS NavStar with BDDIIR:• NS 41
• 1 Russian spacecraft GLONASS-94 with DIERA2 particles detector
0
500
1000
1500
2000
2500
1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Year
F10
.7 (W
.m-2
.Hz-1
)
250
200
150
100
50
Jan-92Jan-88 Jan-96 Jan-00 Jan-04 Jan-08
GPS-NS18/BDD2
GPS-NS24/BDD2
GPS-NS28/BDD2
GPS-NS33/BDD2
GPS-NS41/BDD2R
GLONASS-94/DIERA2
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• ONERA MEO-V2 model:
Data analysis:• Sanitized in terms of back-ground, saturation and contamination• Compliant with COSPAR PRBEM: data analysis procedure• Cross-calibration
GOES 08
Protons80-165 MeV
GPS-NS-33
Electrons> 1.32 MeV
GOES-08Protons80-165 MeV
GPS-NS-33Electrons> 1.32 MeV
Contamination
NS24/BDD2 1992/04/29 -1996/04/18
103
105
107
3 5 7 9LEle
. >
0.2
8 M
eV (
cm-2.s
-1.s
r-1)
10-3
10-2
10-1
Saturation
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• ONERA MEO-V2 model:
Construction of the model:
• Based on MEO-V1 model• Mean model on full solar cycle• Energy from 0.28MeV to 1.12MeV
• Improvements with:• NS41 energy up to 2.24MeV• Compliant with IGE-2006*
Global coherence between solar scale electrondynamic @ GEO and GPS orbit
*A.Sicard-Piet., S.Bourdarie, D.Boscher, R.H.W.Friedel: A model for the geostationary electron environment: POLE, from 30 keV to 5.2 MeV, IEEE Trans. Nuc. Sci. 53 (4), 1844-1850, August 2006
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1988 1992 1996 2000 2004 2008
YearE
lect
ron
s F
lux
(cm
-2.s
-1.s
r-1)
GPS > 1.12 MeV LANL > 1.1 MeV
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• ONERA MEO-V2 model:
Calculation & validation:
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
-8 -6 -4 -2 0 2 4 6
Year of the solar cycle (min=0)
Ele
ctr
on
Flu
x (
cm
-2.s
-1.s
r-1
)
> 0.28 MeV > 0.40 MeV > 0.56 MeV > 0.80 MeV
> 1.12 MeV > 1.60 MeV > 2.24 MeV
AE8 Mean vs. MEO V2
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
0.1 1 10
Energy (M eV)
Inte
gra
ted
Flu
x (c
m-2
s-1)
Upper case
Mean case
Best case
AE8 Mean
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• ONERA MEO-V2 model conclusion:• GNSS like orbit• From 0.28MeV to 2.24MeV• Based on 17 years of GPS NavStar and GLONASS data• It is solar cycle dependent• ECSS-E-ST-10-04C standard• ONERA_DESP_LIB http://craterre.onecert.fr/home.html
• But MEO-V2 defined @ GPS altitude• Deviation from this altitude to be defined @ Galileo orbit
Main goal of the ESA project:
"Energetic Electron Environment Models for MEO"
with ONERA, QinetiQ, SSTL and CNES (Co 21403/08/NL/JD)
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• Re-analysis database used to extract the electron environment at Galileo altitude over more than a solar cycle
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• Relative importance of Galileo orbital planes• Galileo spacecrafts in different orbital planes• Orbit drift around the earth (360° per year)• Magnetic equator crossed each 6 hours
First sketch: importance of orbital plane
• 24 virtual spacecrafts• Separated in local time by 15°• Each orbit covering year 2003• 1 minute time resolution• Altitude 23174km, 56° inclinaison
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
Fluxes extracted from re-analysis data base from 0.1 to 6.4 MeV
-One year average spectrum along each of the 24 GALILEO orbit (year 2003)
-Error % vs energy (the mean flux over the 24 orbital plane is the reference)-LT of maximum year average flux vs energy
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• Relative importance of Galileo orbital planes
Second sketch: importance of the phasing
• Phasing of Galileo spacecraft position• Along a given orbital plane• Worst orbital plane at 0LT• 24 spacecrafts equally separated• Each orbit covering year 2003• 1 minute time resolution• Altitude 23174km, 56° inclinaison
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
Fluxes extracted from re-analysis data base from 0.1 to 6.4 MeV
-One year average spectrum along each of the 24 GALILEO orbit (year 2003)
-Error % vs energy (the mean flux over the 24 orbital plane is the reference)-Orbit index of maximum year average flux vs energy
Orb
it in
dex
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1990 1995 2000 2005
Year
Ele
ctro
n [M
eV-1
cm
-2 s
-1 s
r-1]
50
70
90
110
130
150
170
190
210
230
10.7
cm r
adio
flu
x [s
fu]
0.10MeV
0.20MeV
0.56MeV
1.20MeV
2.24MeV
3.20MeV
4.48MeV
F10.7
• Long term model
Year average flux along Galileo orbit
Galileo long term specification model-Solid lines is Galileo model-Dashed lines is MEO-V2 model
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Latest developments in MEO radiation belt modelsSession 2: Global Navigation Satellite Systems
• Conclusion
• Two MEO models• Solar cycle dependent• No obvious orbital plane dependence• Compliant with IGE-2006 (model @ GEO)• Available around GNSS orbit
• Perspectives
• Worst case definition• ESA project "Energetic Electron Environment Models for MEO":
• Model development• Software development• Validation