DigiTwist is an experimental 2 axis satellite tracker, primarily for the HamTV transmitter on the ISS. 2 broadcast satellite dish positioners are connected together and are controlled by a dual Diseqc pcb.
It is experimental in the sense that the satellite positioners were never meant to be used in this way and may fail. Development is continuing, particularly as to the size of the dish that can be carried. It has not yet been used to receive the ISS, mainly due to lack of opportunity.
A presentation was given at CAT17: https://www.youtube.com/watch?v=qC8CSi8kZTs