EUREF-Czech-2009 - Campaign results

5 Campaign Results

Figure 5. Coordinate residuals at fiducial EPN stations (red) for D variant (non-fiducial EPN stations are plotted with pink).

3D Helmert transformation (translation estimates) was performed for all the combination variants in order to assess the closeness of resulting coordinates to the ETRS89 realization (EPN cumulative product). The estimated translations for each variant using all class ‘A’ stations are within 1.3 mm in East, North and Up component, see Table 2. This result proved that any selection of ten or more fiducial stations in the campaign is reliable for the realization of the ETRS89 reference system at a millimetre level.

Figure 6. Estimated corrections (variant D) for non-EUREF stations (pink points) to the common ETRF2000 velocity field. For all EPN stations (red points) velocities were constrained to the EPN cumulative solution.

The table further shows fulfilled NNT conditions and RMS from coordinate residuals of applied fiducial stations. The solution ‘D’ shows clearly a superior performance while total RMS of Helmert transformation decreased to 1.7 mm. The solution ‘D’ was selected as final also because it includes as many as fiducial stations and excluding only three stations (MATE, and partly GOPE, WROC) with residuals larger than 6 mm in any component. Besides the station selection, Table 3 summarizes residuals from the final solution D and Figure 6 plots their geographical distribution.

Figure 7. North, East and Up repeatabilities for all stations from the final combination (D variant).

Estimated coordinates and velocities in ITRF2005 and ETRF2000 reference frames are summarized in Appendix. Figure 5 visualizes velocity corrections from the final solution (D) with respect to a priori velocities. Velocity differences are very small (bellow 1mm/year) for all stations, but for SNEC and CPRA.

Repeatabilities for all stations were calculated for each variant, but they do not differ significantly – 2mm in horizontal component (only SNEC slightly more) and usually 4 mm in vertical (with a few stations up to 6 mm). Figure 7 shows repeatabilities for final solution (D).

The examples of coordinate time-series from the final combination are given in Figure 9 for three stations – one fiducial (POTS) and two CZEPOS stations (CPAR, CJIH). While CPAR is an example of an excellent performance, CJIH suffers from a seasonal effect probably due to steel mast monumentation. A similar but smaller effect was detected at some other CZEPOS stations with the same type. The time-series of all other stations can be found at http://www.pecny.cz/EUREF-Czech-2009/FINAL-TIMESERIES.