Assessment of the Results of VLBI Intra-Technique Combination Using Regularization Methods

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Tanir E., Heinkelmann R., Schuh H., Kusche J., van Loon J. P.

International Association of Geodesy Symposium, Munich, Germany, 9 - 14 October 2006, vol.134, pp.45-51 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 134
  • Doi Number: 10.1007/978-3-642-00860-3_7
  • City: Munich
  • Country: Germany
  • Page Numbers: pp.45-51
  • Karadeniz Technical University Affiliated: Yes


Various important aspects should be taken into account in the combination of different space geodetic techniques. Consistency of models and standards, quality checks of solutions from individual Analysis Centers (AC), proper scaling of these solutions within the combination process, usage of rigorous combination methods and quality checks of the final combined solution are some of those. In this study, variance component estimation (VCE) is implemented to obtain optimal scaling (weighting) factors for the VLBI (Very Long Baseline Interferometry) intra-technique combination on the basis of normal equations. Afterwards, we apply a Tikhonov-type regularization method to stabilize a combined solution by imposing additional constraints about the solution. The regularization parameters are calculated with two different methods, variance component estimation and generalized cross-validation. The results show that the use of regularization significantly reduces the effect of instability in combined normal equation systems and provides more reasonable results.