8 Conclusions
Altogether 44 Czech national and 18 EPN stations located in other European countries were processed during 4-year campaign and combined coordinates were converted into ETRF2000. For most of the stations 4-year observation time-series were considered, for some shorter time series, but minimally of 1 year. Data from winter periods were excluded for SNEC and LYSH stations located on the top of high mountains.
A high internal consistency of the campaign solution during the whole period is demonstrated by daily coordinate repeatabilities for all stations with a maximum of 2, 2 and 6 mm in North, East and Up component, respectively.
Four variants were tested differing in fiducial station configuration and coordinate and velocities parameterization. No significant difference between the realizations of the ETRS89 was found since all of them agreed within 1.3 mm in three translations.
Finally, 23 fiducial stations were selected for the final realization using a minimum constrained solution (no-net translation) with respect to the EPN cumulative solution (EPN_A_ITRF2005_C1570). Residuals on the fiducial stations demonstrate the consistency of estimated coordinates with ETRS89 at the level of 1.7 mm in total RMS from Helmert transformation and 1.1, 1.2 and 2.5 mm for North, East and Up component, respectively.
An indirect comparison with the previous ETRS89 realization in the Czech Republic could only be applied using coordinates derived in roundabout multi-step approach for all CZEPOS stations (see description of previous realization of ETRS in the Czech Republic in Section 1). The total RMS from the Helmert transformation for 27 stations is 10.2 mm (in 2007.0), while estimated translation parameters were 9.9, -1.7 and 1.1 mm for North, East and Up components, respectively.
The EUREF Technical Working Group was asked to validate the coordinates (not velocities) resulting from this campaign. The campaign was validated at the EUREF TWG meeting on June 1st, 2010, in Gaevle, Sweeden, which was confirmed by resolution No. 1 from the EUREF Symposium 2010 at the same place.