This research presents accuracy analysis of ionospheric corrections embedded in VRS data stream provided by ASG-EUPOS reference network. The analysis are provided for disturbed ionospheric conditions that occurred in November 2013. The research are based on processing VRS station data and comparing the results to processing of real station data located in the same place. In particular, double-differenced ionospheric delay residuals are evaluated and compared. As a reference, double-differenced ionospheric delay residuals under quiet ionospheric conditions were also calculated. The results show that the quality of the ionospheric information embedded in VRS data stream deteriorates during ionospheric disturbances, however, it is still sufficient to support precise GNSS positioning.