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Improvement of the stochastic model of GNSS observables
- Modelling physical
correlation of GNSS phase observations by means of turbulence
theory
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Publications
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Turbulent irregularities in the lower atmosphere cause physical
correlations between GNSS observables. This is also true for VLBI or optical
measurements from SLR, LLR, or the digital zenith camera. Based on turbulence
theory, a variance-covariance model was developed that reflects these
correlations for GPS phase observations. Using this model, a fully-populated
variance-covariance matrice (VCM) for the observations is obtained. The main
results are:
- The obtained VCM depends not
only on the satellite-station geometry but also on the prevailing atmospheric
conditions.
- The amount of the correlation
between two GPS phase observations is inversely related to the separation
distance of the corresponding ray paths through the turbulent
atmosphere.
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« Typical fully populated correlation matrix of
the GPS phase measurements observed during 1h in small GPS network of three
exactly aligned stations (P0, P1,and P2) with distances P0P1 = 1km, P0P2 =
2km.
Further investigations in
this research project will be carried out concerning the following
aspects:
- Influence on the station
coordinates and their VCM
- Analysis of longer
sessions
- Analysis of longer
baselines
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The initial work in this research project was carried out during a
Feodor-Lynen-Fellowship of Steffen Schön at EGMS at Graz University of
Technology with Fritz K. Brunner as his host. He gratefully thanks the
Alexander von Humboldt-Foundation for the support.
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Selected references:
- Schön S. and F.K. Brunner
(2008). A proposal for modelling physical correlations of GPS phase
observations. Journal of Geodesy. online first, DOI 10.1007/s00190-008-0211-3
- Schön S. and F.K. Brunner
(2008). Atmospheric turbulence theory applied to GPS carrier-phase data.
Journal of Geodesy 82(1):47-57, DOI 10.1007/s00190-007-0156-y.
more papers concerning these
topics are available on the webpage of
Steffen
Schön
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Contact person:
Prof. Dr.-Ing. Steffen
Schön |
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