The Slovak real time positioning service (SKPOS) is accessible to their users since the end of the 2006. From the beginning of its establishment represents with the permanent GNSS stations infrastructure the active geodetic controls of Slovakia and realizes reference system ETRS89 in the whole country territory. It is very important to carry out continuous quality monitoring of the service network solution, which is the work focused on, to ensure the administrator and the users as well by its reliability. In the chapters below one can read about infrastructure of SKPOS, the virtual reference station concept and methods of monitoring of the network solution. The main part of thesis is proposal and implementation of the virtual monitoring by the open source software RTKLIB, but also the verification of its precision reached from real monitoring stations. Furthermore at the end the first results of monitoring, their analysis, and also suggestions and ideas for the future.