IGS Workshop, June 02, 2008 1
Validation of GNSS Satellite Orbits
C. Flohrer, G. Beutler, R. Dach, W. Gurtner, U. Hugentobler1, S. Schaer, T. Springer2
Astronomical InstituteUniversity of Bern
1Institut for Astronomical and Physical GeodesyTechnische Universität München
2ESA/European Space Operations CenterDarmstadt
IGS Workshop, Miami BeachJune 2, 2008
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Inhalt
• Introduction
• SLR residuals
• Orbit overlaps
• 14-day peak
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Known Problems
1/year
2/year3/year
4/year6/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
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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
G05
G06
σ 2.2 cm
–3.5 cm
–3.8 cm
σ 2.7 cm
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GLONASS 03
GLONASS 22
GLONASS 24
SLR Validation of GNSS Orbits
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Satellite Standard deviation Offset Number of Residuals
G05 2.2 cm –3.5 cm 11'400
G06 2.7 cm –3.8 cm 10'900
R03 4.9 cm –1.0 cm 17'600
R22 4.6 cm –0.4 cm 21'000
R24 5.1 cm –0.3 cm 12'600
R07 5.7 cm 0.5 cm 3'200
• Results for CODE GNSS orbits
SLR Validation of GNSS Orbits
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u0
SLR Validation of GNSS Orbits
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• Residuals for CODE orbits of G05 and G06, ROCK a priori model
SLR Validation of GNSS Orbits
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• Residuals for CODE orbits of G05 and G06, CODE a priori model
SLR Validation of GNSS Orbits
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• Residuals for CODE GLONASS orbits
SLR Validation of GNSS Orbits
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• Residuals for GFZ GPS orbits
SLR Validation of GNSS Orbits
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• Residuals for IGS GPS orbits
SLR Validation of GNSS Orbits
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SLR Validation of GNSS Orbits
1
2
3
4
5
6
Plane
BLOCK II
BLOCK IIR
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Orbit Overlaps, 1-Day CODE Orbits
radial
alongtrack
crosstrack
G28
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Orbit Overlaps, 1-Day CODE Orbits
40 cm
Pla
ne
2P
lan
e 3
Pla
ne
1
βmax = 78°
βmax = 76°
βmax = 70°
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Orbit Overlaps, 1-Day CODE Orbits
Pla
ne
4P
lan
e 6
Pla
ne
5
βmax = 61°
βmax = 51°
βmax = 40°
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Orbit Overlaps , 1-Day CODE Orbits
Pla
ne
2P
lan
e 3
Pla
ne
1
βmax = 78°
βmax = 76°
βmax = 70°
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Orbit Overlaps , 1-Day CODE Orbits
Pla
ne
4P
lan
e 6
Pla
ne
5
βmax = 61°
βmax = 51°
βmax = 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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• 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
Recommended
