Research on Detection Technologies Under Large Water Conveyance Aqueduct Based on UAV Positioning Navigation

As an important structure in water transfer projects, aqueduct must be regularly tested to identify promptly and solve any potential defect such as cracks. However, there is no proper means to detect aqueducts crossing rivers. In this paper, a possible technical solution for UAV autonomous navigation flight was proposed for detections under aqueducts. For horizontal positioning, the UWB-based positioning technology was used to ensure the UAV positioning when the GPS signals were blocked; the smooth processing was employed in the sensor fusion between the GPS and UWB for seamless switchover between these two modes. For vertical positioning, the fusion of an millimeter wave (MMW) radar, a barometer, and an accelerometer improved the elevation measurement and control accuracy of the UAV, ensuring the auto focusing and clear imaging of the long-focal-length camera. The positioning tests under the aqueduct revealed that, the UAV had better accuracy than 30 cm in horizontal direction and above 10 cm in vertical direction.