1. Direction - Conférence 1

2. 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

3. Direction - Conférence 3 Latest developments in MEO radiation belt models Session 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"

4. Direction - Conférence 4 Latest developments in MEO radiation belt models Session 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

5. Direction - Conférence 5 Latest developments in MEO radiation belt models Session 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 Protons 80-165 MeV GPS-NS-33 Electrons > 1.32 MeV Contamination NS24/BDD2 1992/04/29 -1996/04/18 10 3 10 5 10 7 3 57 9 L Ele. > 0.28 MeV (cm -2.s -1.sr -1 ) 10 -3 10 -2 10 -1 Saturation

6. Direction - Conférence 6 Latest developments in MEO radiation belt models Session 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 electron dynamic @ 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

7. Direction - Conférence 7 Latest developments in MEO radiation belt models Session 2: Global Navigation Satellite Systems ONERA MEO-V2 model: Calculation & validation:

8. Direction - Conférence 8 Latest developments in MEO radiation belt models Session 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.htmlhttp://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)

9. Direction - Conférence 9 Latest developments in MEO radiation belt models Session 2: Global Navigation Satellite Systems Re-analysis database used to extract the electron environment at Galileo altitude over more than a solar cycle

10. Direction - Conférence 10 Latest developments in MEO radiation belt models Session 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

11. Direction - Conférence 11 Latest developments in MEO radiation belt models Session 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

12. Direction - Conférence 12 Latest developments in MEO radiation belt models Session 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

13. Direction - Conférence 13 Latest developments in MEO radiation belt models Session 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 Orbit index

14. Direction - Conférence 14 Latest developments in MEO radiation belt models Session 2: Global Navigation Satellite Systems 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

15. Direction - Conférence 15 Latest developments in MEO radiation belt models Session 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