1. IGS Workshop, June 02, 2008 1 Validation of GNSS Satellite Orbits C. Flohrer, G. Beutler, R. Dach, W. Gurtner, U. Hugentobler 1, S. Schaer, T. Springer 2 Astronomical Institute University of Bern 1 Institut for Astronomical and Physical Geodesy Technische Universität München 2 ESA/European Space Operations Center Darmstadt IGS Workshop, Miami Beach June 2, 2008

2. IGS Workshop, June 02, 2008 2 Inhalt Introduction SLR residuals Orbit overlaps 14-day peak

3. IGS Workshop, June 02, 2008 3 Known Problems 1/year 2/year 3/year 4/year 6/year 350·1/6 days Spectra of coordinate time series of IGS stationen draconitic GPS year, most probably due to orbit modeling deficiencies Ray, 2006

4. IGS Workshop, June 02, 2008 4 Known Problems

5. IGS Workshop, June 02, 2008 5 Known Problems

6. IGS Workshop, June 02, 2008 6 Known Problems

7. IGS Workshop, June 02, 2008 7 SLR Validation of GNSS Orbits G05 G06 σ 2.2 cm –3.5 cm –3.8 cm σ 2.7 cm

8. IGS Workshop, June 02, 2008 8 GLONASS 03 GLONASS 22 GLONASS 24 SLR Validation of GNSS Orbits

9. IGS Workshop, June 02, 2008 9 SatelliteStandard deviationOffsetNumber of Residuals G052.2 cm–3.5 cm11'400 G062.7 cm–3.8 cm10'900 R034.9 cm–1.0 cm17'600 R224.6 cm–0.4 cm21'000 R245.1 cm–0.3 cm12'600 R075.7 cm 0.5 cm 3'200 Results for CODE GNSS orbits SLR Validation of GNSS Orbits

10. IGS Workshop, June 02, 2008 10  0 SLR Validation of GNSS Orbits

11. IGS Workshop, June 02, 2008 11 Residuals for CODE orbits of G05 and G06, ROCK a priori model SLR Validation of GNSS Orbits

12. IGS Workshop, June 02, 2008 12 Residuals for CODE orbits of G05 and G06, CODE a priori model SLR Validation of GNSS Orbits

13. IGS Workshop, June 02, 2008 13 Residuals for CODE GLONASS orbits SLR Validation of GNSS Orbits

14. IGS Workshop, June 02, 2008 14 Residuals for GFZ GPS orbits SLR Validation of GNSS Orbits

15. IGS Workshop, June 02, 2008 15 Residuals for IGS GPS orbits SLR Validation of GNSS Orbits

16. IGS Workshop, June 02, 2008 16 SLR Validation of GNSS Orbits 1 2 3 4 5 6 Plane BLOCK II BLOCK IIR

17. IGS Workshop, June 02, 2008 17 Orbit Overlaps, 1-Day CODE Orbits radial alongtrack crosstrack G28

18. IGS Workshop, June 02, 2008 18 Orbit Overlaps, 1-Day CODE Orbits 40 cm Plane 2 Plane 3 Plane 1 β max = 78° β max = 76° β max = 70°

19. IGS Workshop, June 02, 2008 19 Orbit Overlaps, 1-Day CODE Orbits Plane 4 Plane 6 Plane 5 β max = 61° β max = 51° β max = 40°

20. IGS Workshop, June 02, 2008 20 Orbit Overlaps, 1-Day CODE Orbits Plane 2 Plane 3 Plane 1 β max = 78° β max = 76° β max = 70°

21. IGS Workshop, June 02, 2008 21 Orbit Overlaps, 1-Day CODE Orbits Plane 4 Plane 6 Plane 5 β max = 61° β max = 51° β max = 40°

22. IGS Workshop, June 02, 2008 22 Orbit Overlaps, Amplitude Spectra

23. IGS Workshop, June 02, 2008 23 Mean Power Spectrum, 14-Day Line

24. IGS Workshop, June 02, 2008 24 Mean Power Spectrum, 14-Day Line

25. IGS Workshop, June 02, 2008 25 Mean Power Spectrum, 14-Day Line

26. IGS Workshop, June 02, 2008 26 Mean Power Spectrum, 14-Day Line

27. IGS Workshop, June 02, 2008 27 Mean Power Spectrum, 14-Day Line

28. IGS Workshop, June 02, 2008 28 Mean Power Spectrum, 14-Day Line

29. IGS Workshop, June 02, 2008 29 Mean Power Spectrum, 14-Day Line

30. IGS Workshop, June 02, 2008 30 Mean Power Spectrum, 14-Day Line

31. IGS Workshop, June 02, 2008 31 Mean Power Spectrum, 14-Day Line

32. IGS Workshop, June 02, 2008 32 Mean Power Spectrum, 14-Day Line

33. IGS Workshop, June 02, 2008 33 Phase Spectrum, Plane-specific

34. IGS Workshop, June 02, 2008 34 Phase Spectrum, Plane-specific

35. IGS Workshop, June 02, 2008 35 Phase Spectrum, Plane-specific

36. IGS Workshop, June 02, 2008 36 Phase Spectrum, Plane-specific

37. IGS Workshop, June 02, 2008 37 Phase Spectrum, Plane-specific

38. IGS Workshop, June 02, 2008 38 Phase Spectrum, Plane-specific

39. IGS Workshop, June 02, 2008 39 Phase Spectrum, Mean for Planes

40. IGS Workshop, June 02, 2008 40 Power Spectra of Helmert Parameters

41. IGS Workshop, June 02, 2008 41 Power Spectra of Helmert Parameters

42. IGS Workshop, June 02, 2008 42 Power Spectra of Helmert Parameters

43. IGS Workshop, June 02, 2008 43 Power Spectra of Helmert Parameters

44. IGS Workshop, June 02, 2008 44 Power Spectra of Helmert Parameters

45. IGS Workshop, June 02, 2008 45 Power Spectra of Helmert Parameters

46. IGS Workshop, June 02, 2008 46 CODE 1d Solution, 24h Pole Estimate

47. IGS Workshop, June 02, 2008 47 CODE 1d Solution, 2h Pole Estimate

48. IGS Workshop, June 02, 2008 48 Orbit modeling problems affect the entire solution Orbit periods are found in station positions and geocenter motion SLR Residuals show a characteristic pattern Patterns in orbit overlap time series seem not to be influenced by the a priori orbit model Patterns depend on the maximum elevation of the Sun above the orbital plane which indicates problems with the estimated empirical orbit parameters Prominent peak at 14-days In alongtrack and crosstrack directions In phase for all satellites Period seems to be related to tidal corrections in the system orientation Probably due to the used subdaily pole model Conclusions