I know the quintus pilot quite well and he is very happy with the vario and obviously still flying with it. So happy that his wife, who flies a 31 , now also has one.
The installation involves 2 rather large ( about 100mm) professional GPS antennas in the glider. One in the cockpit and the other one on top of the fuselage halfway near the tail. You barely notice it.
They work on the normal GPS signals from the US , Galileo and the other ones if available, like car navigation only a lot more accurate and for vertical speed.
Mike has made an amazing innovation for gliding.