Table 2 Comparison of VLBI CONT campaigns. During CONT11, 14 stations participated, but one of them, Warkworth, New Zealand, only observed for a few hours and was therefore excluded from the analysis. The number of observation epochs given below is equivalent to the number of state updates performed in the KF. Usually, only one scan (i.e., the observation of a particular radio source) is scheduled at a time, but in some cases sub-networks perform different scans at the same time. Thus, the number of observation epochs is slightly lower compared to the number of scans. The numbers take into account that some observations flagged as outliers were removed. In the correlation process, the CONT campaigns are split into sessions lasting 24 h each. These start at 18:00 for CONT02, 17:00 for CONT05, and 0:00 for the others

From: Tropospheric delay determination by Kalman filtering VLBI data