Real-Time Positioning Method for UAVs in Complex Structural Health Monitoring Scenarios

UAVs are becoming increasingly used in the field of structural health monitoring, and the position information of them during the tasks is crucial. However, in complex scenarios such as bridges and high-rise buildings, the GNSS positioning method cannot obtain the positions of the UAV all the time due to the blockage of satellite signals and multi-path effects. This paper proposes a real-time positioning method to address the issue combining GNSS and total station. The GNSS is first used to locate the UAV when it is not in the line of sight of the total station, and the coordinates of the UAV are transmitted to the total station for blind tracking through coordinates conversion. The total station is then used to directly track the UAV when it flies to the GNSS-denied area and appears in the field view of the total station. Experiments show that the shift from blind tracking to direct tracking can be guaranteed as the coordinates conversion error is always less than the field of view range of the total station, even if only two common points are used for coordinates conversion. In addition, high positioning accuracy can be achieved in complex structural health monitoring scenarios.