It is interesting from a control and collision avoidance perspective for sure. Unfortunately the company behind it doesn't really reveal any details
https://dronisos.fr/know-how/ Would guess they are just using an IMU to predict changes but might be more computer vision going on with all the video data being streamed to a control machine that does the heavy computation and sends it back out to the quads. Only way I've really seen this done otherwise is using IR markers on the quads and an array of cameras in a room to track the position of all of them with high accuracy. I don't think GPS would work in an indoor facility like that (they could use bluetooth beacons but I don't think those give you the kind of resolution of position you'd need).
Skydio makes a standalone quad that can do live object detection and avoidance as well as tracking a target and predicting its path to follow a person or other moving object:
https://www.skydio.com/ comes at a serious cost but has 12 or 13 cameras in it and an nvidia GPU for doing all the processing on board.