Found this, interesting use of a UAV.
I'm betting (although would like to be proved contrary) that all the wicked awesome accurate positioning is done with high speed camera(s) & computers located at strategic locations around the room.
The position is found and processed by the cameras and computers, then RF commands are sent to the bots.
Yep, read about it here :)
Everytime I see a quadrocopter do something radical like this it makes me want to get a spendy IMU to start tinkering! ... soon enough