The plot shows the differences in North, East and Up between the station positions obtained from each cumulative solution (available each 15 weeks).
Each point in the plot shows the station position obtained from a cumulative solution. The time stamp of the point is the epoch of the last GPS Week for which data for this station were included in the cumulative solution. With time, and with the inclusion of more observations in the cumulative solution, the estimated station positions should normally converge.
The red dots indicate the estimated cumulative positions during the period that the station was a Class B station (always the first step in a station history). These positions are given at the epoch of minimal variance.
The green dots indicate the estimated cumulative positions during the period that the station is a Class A station. These positions are given at the epoch 2005.0.
The vertical blue line means a new solution number (equipment change) has been introduced and an orange vertical line indicates when the station is withdrawn from EPN (but still appears in the cumulative solution).