Performance of the Operational IVS-R1 and IVS-R4 Sessions

This paper focuses on the performance of the operational IVS-R1 and IVS-R4 sessions from 2002 through 2017. The formal uncertainties of the IVS-R1 and IVS-R4 EOPs improved over the period of 2002 through 2017. We consider how much this improvement can be attributed to the increased size of the networks, changes in the data rate, the number of observed sources, and/or the scheduling parameters.