Combination of GPS and VLBI on the observation level during CONT11—common parameters, ties and inter-technique biases


Multi-technique space geodetic analysis software has been developed which allows to combine data on the observation level. In addition to local tie information, site-wise common parameters, i.e., troposphere and clocks, can be estimated with this software. Thus, it will be discussed how common parameters have to be estimated and where biases/offsets need to be taken into account. To test such a novel concept, Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI) data from the CONT11 campaign are being utilized. Since the VLBI baselines of this campaign extend over several thousands of kilometers, GPS data are processed in precise-point positioning mode and satellite orbits and clocks are kept fixed to the IGS final products. From the obtained results, it can be shown that the combination of space geodetic data on the observation level leads to a consistent improvement of station position repeatability as well as nuisance parameters like troposphere estimates. Furthermore, estimation of common parameters (troposphere or clocks) at co-located sites helps to improve the solution further and derive an utmost physically consistent model of the concerned parameters.

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Parts of this work were supported by a Grant-in-Aid for Scientific Research. The International GNSS Service (Dow et al. 2009) and the International VLBI Service for Geodesy and Astrometry (Schuh and Behrend 2012) are acknowledged for providing data. Design and implementation of c5++ were a huge effort, requiring the participation and support of many individuals.

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Hobiger, T., Otsubo, T. Combination of GPS and VLBI on the observation level during CONT11—common parameters, ties and inter-technique biases. J Geod 88, 1017–1028 (2014).

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  • GPS
  • VLBI
  • Combination
  • GGOS