An Experimental Study of Aerial Stereo Visual Odometry

Unmanned aerial vehicles normally rely on GPS to provide pose information for navigation. In this work, we examine stereo visual odometry (SVO) as an alternative pose estimation method for situations in which GPS in unavailable. SVO is an incremental procedure that determines ego-motion by identifying and tracking visual landmarks in the environment, using cameras mounted on-board the vehicle. We present experiments demonstrating how SVO performance varies with camera pointing angle, for a robotic helicopter platform. Our results show that an oblique camera pointing angle produces better motion estimates than a nadir view angle, and that reliable navigation over distances of more than 200 meters is possible using visual information alone.