Indoor path planning for hex-rotor aircraft with landmark-based visual navigation

In this paper, a indoor path planning algorithm is presented to obtain the shortest trajectory for the hex-rotor aircraft in the complex terrains with no-fly zones. This algorithm finds all flyable and feasible trajectories from the start point to the landmarks and from the landmarks to the destination point firstly. Then, it constructs the path network between all landmarks and connects the start point, all landmarks and the destination point. Finally, it finds the final navigable trajectory. To overcome the drawbacks of Global Positioning System (GPS) and improve the positioning accuracy, the visual navigation based on landmarks is employed to assist the Inertial Navigation System (INS). It is accomplished by comparing the corresponding position of landmarks in the real-time image and onboard stored integral referenced image. The landmarks must be visible and distinguishable. The results of simulations and actual indoor flights show that the algorithm proposed in this paper was feasible for path planning and it can be used in indoor and outdoor environments.