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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
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Inhalt

• Introduction
• SLR residuals
• Orbit overlaps
• 14-day peak

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Known Problems

• Spectra of coordinate time series of IGS
  stationen
• draconitic GPS year, most probably due to orbit
  modeling deficiencies

Ray, 2006
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Known Problems
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Known Problems
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Known Problems
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SLR Validation of GNSS Orbits
s 2.2 cm
G05
s 2.7 cm
G06
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SLR Validation of GNSS Orbits
GLONASS 03
GLONASS 22
GLONASS 24
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SLR Validation of GNSS Orbits

• Results for CODE GNSS orbits

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SLR Validation of GNSS Orbits
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SLR Validation of GNSS Orbits

• Residuals for CODE orbits of G05 and G06, ROCK a
  priori model

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SLR Validation of GNSS Orbits

• Residuals for CODE orbits of G05 and G06, CODE a
  priori model

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SLR Validation of GNSS Orbits

• Residuals for CODE GLONASS orbits

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SLR Validation of GNSS Orbits

• Residuals for GFZ GPS orbits

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SLR Validation of GNSS Orbits

• Residuals for IGS GPS orbits

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SLR Validation of GNSS Orbits
Plane
1
BLOCK II
2
3
4
5
BLOCK IIR
6
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Orbit Overlaps, 1-Day CODE Orbits
G28
radial
alongtrack
crosstrack
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Orbit Overlaps, 1-Day CODE Orbits
Plane 2
ßmax 78
Plane 3
ßmax 76
Plane 1
ßmax 70
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Orbit Overlaps, 1-Day CODE Orbits
Plane 4
ßmax 61
Plane 6
ßmax 51
Plane 5
ßmax 40
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Orbit Overlaps , 1-Day CODE Orbits
Plane 2
ßmax 78
Plane 3
ßmax 76
Plane 1
ßmax 70
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Orbit Overlaps , 1-Day CODE Orbits
Plane 4
ßmax 61
Plane 6
ßmax 51
Plane 5
ßmax 40
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Orbit Overlaps, Amplitude Spectra
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Mean Power Spectrum, 14-Day Line
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Phase Spectrum, Plane-specific
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Phase Spectrum, Plane-specific
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Phase Spectrum, Plane-specific
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Phase Spectrum, Plane-specific
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Phase Spectrum, Plane-specific
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Phase Spectrum, Plane-specific
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Phase Spectrum, Mean for Planes
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Power Spectra of Helmert Parameters
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Power Spectra of Helmert Parameters
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Power Spectra of Helmert Parameters
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Power Spectra of Helmert Parameters
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Power Spectra of Helmert Parameters
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Power Spectra of Helmert Parameters
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CODE 1d Solution, 24h Pole Estimate
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CODE 1d Solution, 2h Pole Estimate
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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