The VLNS station has a category of class A, which means that its positions have 1 cm accuracy during all epochs of the time span of the used observations (Fig.
VLNS data are processed in four EUREF analysing centres--Nordic Geodetic Commission (NKG) from GPS week 0998, Geodetic Observatory Pecny (GOP) from GPS week 0998, Warsaw University of Technology (WUT) from GPS week 0998 and Military University of Technology (MUT)--from GPS week 1558, leading to a weekly combined solution and time series (Kenyers 2009).
VLNS data have been processed within the EUREF network since 1999 when VLNS was included in the EUREF permanent network.
The gap in data between the spring of 1999 and that of 2002 occurred because of the fault of the GPS receiver and due to the fact that the VLNS station was temporarily excluded from the combined EUREF solution.
The evolution of weekly VLNS coordinates in the ITRF system is shown in Fig.