EPOSA stands for a GNSS real-time positioning service which offers its customers observation corrections valid over the whole Austrian territory. It is based on the observation data of 37 well distributed GNSS reference sites. The brand EPOSA, emerged from the cooperation of the companies ÖBB, BEWAG and WIENSTROM, was presented to the public for the first time in autumn 2009. The challenge within reference networks is to model distance-dependent errors from GNSS-observations of the reference stations and to forward them as correction-data in real time. The users are interested to determine their position with cm-accuracy, ideally within a few seconds. The requirements on the network performance asked for from user side are extremely demanding. The quality of the corrections should be as good as necessary to achieve cm-accuracy. Furthermore, the service should be available any time with high reliability. The aim of this study is to examine at which level these requirements are guaranteed by the EPOSA service. To complete this task the network operator has provided data covering a full month, which allowed to observe the status-parameters of the network. The quality of every reference station was evaluated by means of the signal to noise ratio, occurring multipath and possible obstructions. In addition, the status data were evaluated with regard to the availability of the service, the time to fix the ambiguities within the network and the time for initialization at rover site. Over the period September 2009 the availability of the service was ensured to 94%. Potential for improvement has been identified with respect to the fixing time of the ambiguities of observations in low elevation which relates to the achievable quality of the correction parameters. At almost all stations a very good performance could be achieved. By taking advantage of the real-time correction data of the EPOSA network the user is able to establish high accurate positions at the few cm level even in alpine areas with an occupation time between 30sec up to 2 minutes.