DTRF2020 Combination Strategy

The calculation of the DTRF2020 follows a 2-step approach (displayed by the figure below) which initially provides individual technique-specific multi-year solutions (NEQs), which are then combined to the DTRF2020. The approach is fully based on the manipulation and combination of normal equation systems, NEQs.

2-step approach

• step-1: computation of technique-specific multi-year TRF solutions and consistent EOP series comprising the "Analysis and reduction" and "Computation of single TRF NEQ and solution per technique" in the processing scheme below.
• step-2: combination of the technique-specific TRFs and EOP series on NEQ level and computation of the DTRF2020 represented by the "Generation of DTRF2020 NEQ and solution" in the processing scheme below. It comprises also the central part of DTRF2020 datum realization
   

New components in DTRF2020 combination strategy

• reduction of the single input NEQs by the summed non-tidal loading effect on station positions
• approximation of post-seismic deformation by combinations of logarithmic and exponential functions using the newly developed software APROPOS. Reduction of the single input NEQs by the approximation time series.