Performance Evaluation of Vision-Based Navigation and Landing on a Rotorcraft Unmanned Aerial Vehicle

A rotorcraft UAV provides an ideal experimental platform for vision-based navigation. This paper describes the flight tests of the US Army PALACE project, which implements Moravec´s pseudo-normalized correlation tracking algorithm. The tracker uses the movement of the landing site in the camera, a laser range, and the aircraft attitude from an IMU to estimate the relative motion of the UAV. The position estimate functions as a GPS equivalent to enable the rotorcraft to maneuver without the aid of GPS. With GPS data as a baseline, tests were performed in simulation and inflight that measure the accuracy of the position estimation