Here is a video I shot on Monday of a real world UAV flight. I use computer vision and augmented reality techniques to overlay a HUD that shows what the onboard EKF is thinking (the EKF is fancy math that estimates roll, pitch, yaw, velocities, positions, sensor biases, etc.) It also draws what the autopilot is doing using intuitive symbology. Finally it draws the flight path back into the video so you can see where you've flown. The video shows a hand launch in manual mode, switch over to autonomous flight, then fades to a portion of a the circle hold (showing the path repeatability/variation), then fades to an autonomous landing, and finally I pick up the aircraft, walk back to the runway center and pan the camera around to show (using augmented reality) where the aircraft has been flying and what the approach looked like: