Quarterly

Introduction

Combination Procedure

  1. Before accumulating the individual normal equation matrices, the parameter epochs are transformed to the mean epoch of all contributions by using the respective Earth Orientation Parameter rates and regularisation according to the IERS Conventions 2010.
  2. Furthermore, the individual normal equations are be transformed to a common set of a priori values for station coordinates and Earth Orientation Parameters.
  3. Weighting factors determined by variance component estimation are applied to the normal equation systems.
  4. The datum-free normal equation systems are accumulated.
  5. Earth Orientation Parameters are estimated, whereby the geodetic datum is realised by fixing all station coordinates to their a priori values.
  6. To perform a quality check, comparisons are carried out, namely
    • internal comparisons between the individual solutions and the combined solution,
    • external comparisons against

Notice: To get comparable results, the calculations of bias, WRMS and RMS are carried out only for those sessions that were analysed by all Analysis Centres.