Inhalt

1. Validation of GNSS Satellite OrbitsC. Flohrer, G. Beutler, R. Dach, W. Gurtner, U. Hugentobler1, S. Schaer, T. Springer2Astronomical InstituteUniversity of Bern1Institut for Astronomical and Physical GeodesyTechnische Universität München2ESA/European Space Operations CenterDarmstadtIGS Workshop, Miami BeachJune 2, 2008

2. Inhalt • Introduction • SLR residuals • Orbit overlaps • 14-day peak

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

4. Known Problems

5. Known Problems

6. Known Problems

7. –3.5 cm –3.8 cm SLR Validation of GNSS Orbits σ 2.2 cm G05 σ 2.7 cm G06

8. SLR Validation of GNSS Orbits GLONASS 03 GLONASS 22 GLONASS 24

9. SLR Validation of GNSS Orbits • Results for CODE GNSS orbits

10. 0 D SLR Validation of GNSS Orbits

11. SLR Validation of GNSS Orbits • Residuals for CODE orbits of G05 and G06, ROCK a priori model

12. SLR Validation of GNSS Orbits • Residuals for CODE orbits of G05 and G06, CODE a priori model

13. SLR Validation of GNSS Orbits • Residuals for CODE GLONASS orbits

14. SLR Validation of GNSS Orbits • Residuals for GFZ GPS orbits

15. SLR Validation of GNSS Orbits • Residuals for IGS GPS orbits

16. SLR Validation of GNSS Orbits Plane 1 BLOCK II 2 3 4 5 BLOCK IIR 6

17. Orbit Overlaps, 1-Day CODE Orbits G28 radial alongtrack crosstrack

18. 40 cm Orbit Overlaps, 1-Day CODE Orbits Plane 2 βmax = 78° Plane 3 βmax = 76° Plane 1 βmax = 70°

19. Orbit Overlaps, 1-Day CODE Orbits Plane 4 βmax = 61° Plane 6 βmax = 51° Plane 5 βmax = 40°

20. Orbit Overlaps , 1-Day CODE Orbits Plane 2 βmax = 78° Plane 3 βmax = 76° Plane 1 βmax = 70°

21. Orbit Overlaps , 1-Day CODE Orbits Plane 4 βmax = 61° Plane 6 βmax = 51° Plane 5 βmax = 40°

22. Orbit Overlaps, Amplitude Spectra

23. Mean Power Spectrum, 14-Day Line

24. Mean Power Spectrum, 14-Day Line

25. Mean Power Spectrum, 14-Day Line

26. Mean Power Spectrum, 14-Day Line

27. Mean Power Spectrum, 14-Day Line

28. Mean Power Spectrum, 14-Day Line

29. Mean Power Spectrum, 14-Day Line

30. Mean Power Spectrum, 14-Day Line

31. Mean Power Spectrum, 14-Day Line

32. Mean Power Spectrum, 14-Day Line

33. Phase Spectrum, Plane-specific

34. Phase Spectrum, Plane-specific

35. Phase Spectrum, Plane-specific

36. Phase Spectrum, Plane-specific

37. Phase Spectrum, Plane-specific

38. Phase Spectrum, Plane-specific

39. Phase Spectrum, Mean for Planes

40. Power Spectra of Helmert Parameters

41. Power Spectra of Helmert Parameters

42. Power Spectra of Helmert Parameters

43. Power Spectra of Helmert Parameters

44. Power Spectra of Helmert Parameters

45. Power Spectra of Helmert Parameters

46. CODE 1d Solution, 24h Pole Estimate

47. CODE 1d Solution, 2h Pole Estimate

48. Conclusions • 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