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**Harvard**

Heinkelmann, R., Boehm, J., Bolotin, S., Engelhardt, G., Haas, R., Lanotte, R., MacMillan, D., Negusini, M., Skurikhina, E., Titov, O. och Schuh, H. (2011) *VLBI-derived troposphere parameters during CONT08*.

** BibTeX **

@article{

Heinkelmann2011,

author={Heinkelmann, R. and Boehm, J. and Bolotin, S. and Engelhardt, G. and Haas, Rüdiger and Lanotte, R. and MacMillan, D. S. and Negusini, M. and Skurikhina, E. and Titov, O. and Schuh, H.},

title={VLBI-derived troposphere parameters during CONT08},

journal={Journal of Geodesy},

issn={0949-7714},

volume={85},

issue={7},

pages={377-393},

abstract={Time-series of zenith wet and total troposphere delays as well as north and east gradients are compared, and zenith total delays (ZTD) are combined on the level of parameter estimates. Input data sets are provided by ten Analysis Centers (ACs) of the International VLBI Service for Geodesy and Astrometry (IVS) for the CONT08 campaign (12-26 August 2008). The inconsistent usage of meteorological data and models, such as mapping functions, causes systematics among the ACs, and differing parameterizations and constraints add noise to the troposphere parameter estimates. The empirical standard deviation of ZTD among the ACs with regard to an unweighted mean is 4.6 mm. The ratio of the analysis noise to the observation noise assessed by the operator/software impact (OSI) model is about 2.5. These and other effects have to be accounted for to improve the intra-technique combination of VLBI-derived troposphere parameters. While the largest systematics caused by inconsistent usage of meteorological data can be avoided and the application of different mapping functions can be considered by applying empirical corrections, the noise has to be modeled in the stochastic model of intra-technique combination. The application of different stochastic models shows no significant effects on the combined parameters but results in different mean formal errors: the mean formal errors of the combined ZTD are 2.3 mm (unweighted), 4.4 mm (diagonal), 8.6 mm [variance component (VC) estimation], and 8.6 mm (operator/software impact, OSI). On the one hand, the OSI model, i.e. the inclusion of off-diagonal elements in the cofactor-matrix, considers the reapplication of observations yielding a factor of about two for mean formal errors as compared to the diagonal approach. On the other hand, the combination based on VC estimation shows large differences among the VCs and exhibits a comparable scaling of formal errors. Thus, for the combination of troposphere parameters a combination of the two extensions of the stochastic model is recommended.},

year={2011},

keywords={VLBI, Troposphere parameters, Intra-technique combination, terrestrial reference frame, geodesy, interferometry, gps },

}

** RefWorks **

RT Journal Article

SR Electronic

ID 143385

A1 Heinkelmann, R.

A1 Boehm, J.

A1 Bolotin, S.

A1 Engelhardt, G.

A1 Haas, Rüdiger

A1 Lanotte, R.

A1 MacMillan, D. S.

A1 Negusini, M.

A1 Skurikhina, E.

A1 Titov, O.

A1 Schuh, H.

T1 VLBI-derived troposphere parameters during CONT08

YR 2011

JF Journal of Geodesy

SN 0949-7714

VO 85

IS 7

SP 377

OP 393

AB Time-series of zenith wet and total troposphere delays as well as north and east gradients are compared, and zenith total delays (ZTD) are combined on the level of parameter estimates. Input data sets are provided by ten Analysis Centers (ACs) of the International VLBI Service for Geodesy and Astrometry (IVS) for the CONT08 campaign (12-26 August 2008). The inconsistent usage of meteorological data and models, such as mapping functions, causes systematics among the ACs, and differing parameterizations and constraints add noise to the troposphere parameter estimates. The empirical standard deviation of ZTD among the ACs with regard to an unweighted mean is 4.6 mm. The ratio of the analysis noise to the observation noise assessed by the operator/software impact (OSI) model is about 2.5. These and other effects have to be accounted for to improve the intra-technique combination of VLBI-derived troposphere parameters. While the largest systematics caused by inconsistent usage of meteorological data can be avoided and the application of different mapping functions can be considered by applying empirical corrections, the noise has to be modeled in the stochastic model of intra-technique combination. The application of different stochastic models shows no significant effects on the combined parameters but results in different mean formal errors: the mean formal errors of the combined ZTD are 2.3 mm (unweighted), 4.4 mm (diagonal), 8.6 mm [variance component (VC) estimation], and 8.6 mm (operator/software impact, OSI). On the one hand, the OSI model, i.e. the inclusion of off-diagonal elements in the cofactor-matrix, considers the reapplication of observations yielding a factor of about two for mean formal errors as compared to the diagonal approach. On the other hand, the combination based on VC estimation shows large differences among the VCs and exhibits a comparable scaling of formal errors. Thus, for the combination of troposphere parameters a combination of the two extensions of the stochastic model is recommended.

LA eng

DO 10.1007/s00190-011-0459-x

LK http://dx.doi.org/10.1007/s00190-011-0459-x

LK http://publications.lib.chalmers.se/records/fulltext/local_143385.pdf

OL 30