Ionospheric impact on the performance of GNSS reference networks

The ionospheric influence on reference networks has been proven at daily and longer-term levels and can be a significant error factor. The impact is noticeably stronger during ionospheric perturbations and storms, which raises the question about reliability of GNSS reference networks during such unfavourable conditions. Addressed here are potential problems of present day GNSS reference network concepts, particularly problems that can be related to ionospheric interference. Presented also are case studies of adverse space weather effects on positioning. Analysed are the feasibility and effectivity of a space weather operational service for mitigation purposes