Accurate Tropospheric Correction for Local GPS Monitoring Networks With Large Height Differences

Steffen Schön, Andreas Wieser and Klaus Macheiner

Abstract:	Tropospherically induced distortions of point coordinates are still a major error source when using GPS for high precision geodetic monitoring applications. Using data from a local GPS landslide monitoring network (height differences up to 900 m), we found that the apparent height variations caused by residual tropospheric propagation effects can reach up to 6 cm if only a priori tropospheric models are applied. This is an order of magnitude worse than the required accuracy of better than 0.5 cm. It can be shown that the apparent height variations in each monitoring station depend linearly on the height difference with respect to the stable reference station. This proportionality is the key and the starting point for the development of the correction models. We discuss two approaches to mitigate such errors, one in the observation domain and one in the coordinate domain. Both approaches exploit the height dependence of the relative tropospheric delay among stations subject to the same atmospheric conditions. The results show that both approaches reduce most of the bias of the height component, e.g., typical long periodic distortions of up to 6 cm during 3 hours are reduced to less than 1cm. This is a reduction of over 80%.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	250 - 260
Cite this article:	Schön, Steffen, Wieser, Andreas, Macheiner, Klaus, "Accurate Tropospheric Correction for Local GPS Monitoring Networks With Large Height Differences," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 250-260.
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