An efficient UAV navigation solution for confined but partially known indoor environments

This paper presents a robust and efficient navigation solution for a quadrotor UAV to perform autonomous flight in a confined but partially known indoor environment. The main sensors used onboard of the UAV are two scanning laser range finders and an inertial measurement unit. When the indoor environment is structured and the coordinates of its key corner features are known, the UAV planer position can be efficiently calculated via the measurements from the first horizontally scanning laser range finder. The height of the UAV with respect to the ground can be robustly estimated by the second laser scanner which is mounted orthogonally to the first. Besides, this work also adopts a robust and perfect tracking control method with integral action to enable the UAV to track any smooth 3-D trajectories responsively and precisely. All computation is done onboard by an ARM-based embedded computer with limited processing power. The whole system was successfully tested in the 2013 Singapore Amazing Flying Machine Competition and helped the Unmanned Aircraft Systems Group from the National University of Singapore win the overall championship in the fully autonomous category.