In this calculation, phase measurements were used (double
differences), at 30-second intervals, IGS precise satellite
orbits and clock parameters, a cut-off elevation angle of
7 degrees and the Vienna Mapping Functions 1 (VMF1)
(Boehm et al., 2006a). Atmospheric parameters were estimated
at 30 min intervals (interpolated to 15 min intervals)
using the “metutil” GAMIT routine.