Vision-based Autonomous Drone racing in GPS-denied Environments

Abstract

High-speed autonomous flight of Micro Air Vehicles has gained much attention in recent years. However, flight in complex GPS-denied environments still poses a serious challenge. One scenario which contains these elements is drone racing, where pilots have to fly complex tracks at high speed, often in an indoor environment. In this work we therefore present an MAV capable of autonomously flying such a drone race track. The system has to operate in a GPS-denied environment, hence a visual navigation method is employed. Position is recovered from gate detections based on a novel least-squares method, while heading is estimated using an optimization based method. Experiments show that both methods have a higher accuracy than the standard P3P pose estimation method. Furthermore, a state estimation filter is designed to fuse the visual measurements with IMU measurements, by using an EKF with drag based prediction model. For high-level control different motion primitives are linked, which allow the MAV to fly the track without having a detailed on-board map. The overall approach does not rely on SLAM or Visual odometry, which results in low computational complexity. Also, it does not rely on downward optical flow velocity measurements, which enables it to work even in low texture environments.