I would bet that modem is using a phased antenna array [1]
(I'm guessing this is what "solid state, no moving parts" means on the product page). With the right sensors (gyros, etc), a solid-state system like that should be able to keep a pretty tight lock on the satellite even in the roughest conditions.
Look at the Terminal Equipment tab of this page linked below. It shows the Cobham ( different manufacturer from Thales) antenna for the same satellite service. It looks like it is a set of six or so patch antennas. It's not clear if it is switching between patches or combining the signals to/from the patches. If the latter, it is indeed a phased array. That seems likely because the other manufacturer, Intellian, describes their antenna as a 12-element phased array. I'm guessing the Thales also uses a phased array.
1. https://en.wikipedia.org/wiki/Phased_array