Autonomous Flight Using UWB-Based Positioning System with Optical Flow Sensors in a GPS-Denied Environment

This study presents the positioning method and au-tonomous flight of a quadrotor drone using ultra-wideband (UWB) communication and an optical flow sensor. UWB communication obtains the distance be-tween multiple ground stations and a mobile station on a robot, and the position is calculated based on a mul-tilateration method similar to global positioning sys-tem (GPS). The update rate of positioning using only UWB communication devices is slow; hence, we im-proved the update rate by combining the UWB and inertial measurement unit (IMU) sensor in the prior study. This study demonstrates the improvement of the positioning method and accuracy by sensor fusion of the UWB device, an IMU, and an optical flow sen-sor using the extended Kalman filter. The proposed method is validated by hovering and position control experiments and also realizes a sufficient rate and ac-curacy for autonomous flight.