Long-term positional monitoring of station VYHL of the Sneznik Network

In the article the results of repeated satellite positional measurements of station VYHL of the Sneznik Network over period 1994-2006 are presented. Altogether 17 Brno University of Technology measuring campaigns were carried out and evaluated. The observation data (acquired mostly with Leica GPS receivers) were processed with the scientific Bernese GPS Software and the commercial Leica SKI-Pro software packets. Unified procedure for campaign data processing including the alignement of the resulting positions to respective EUREF Permanent Network weekly solutions had been adopted. Only the stability in horizontal direction was analysed. Positional stability of the VYHL station was considered in respect to the surrounding IGS, EPN, and local stations which were used for a local reference frame definitions, at three different levels. First level information was obtained from relations to surrounding stations of the Sneznik Network in distances up to 10 km, second level represent the relations to nearest EPN stations in distances about 100 km, and finally third level represent the relations to surrounding IGS Network stations in distances about 300-400 km. Another approach to VYHL stability assessment was the analysis of slope distances time series from VYHL to neighbouring GPS stations. Outlined are also possibilities of exploitation of the recently completed CZEPOS Network. KEYWORDS: geodynamics, GPS, stability monitoring