Short-term UAV path-planning with monocular-inertial SLAM in the loop.

Small Unmanned Aerial Vehicles (UAVs) are some of the most promising robotic platforms in a variety of applications due to their high mobility. Their restricted computational and payload capabilities, however, translate into significant challenges in automating their navigation. With Simultaneous Localization And Mapping (SLAM) systems recently demonstrated to be employable onboard UAVs, the focus fall on path-planning on the quest of achieving autonomous navigation. With the vast body of path-planning literature often assuming perfect maps or maps known a priori, the biggest challenge lies in dealing with the robustness and accuracy limitations of onboard SLAM in real missions. In this spirit, this paper proposes a path-planning algorithm designed to work in the loop of the SLAM estimation of a monocular-inertial system. This point-to-point planner is demonstrated to navigate in an unknown environment using the incrementally generated SLAM map, while dictating the navigation strategy for preferable acquisition of sensor data for better estimations within SLAM. A thorough evaluation testbed of both simulated and real data is presented, demonstrating the robustness of the proposed pipeline against the state-of-the-art and its dramatically lower computational complexity, revealing its suitability to UAV navigation.