I ended up formalizing it into a number of categories: http://www.dronepedia.com/index.php?title=Autopilot_concepts http://www.dronepedia.com/index.php?title=A

I ended up formalizing it into a number of categories: http://www.dronepedia.com/index.php?title=Autopilot_concepts http://www.dronepedia.com/index.php?title=Autopilot_concepts In my view, anything with Return To Home level autopilot and above could reasonably be considered a UAV. This generally requires a 6-9DOF IMU, an altimeter, and a GPS receiver.