GNSS/LiDAR-Based Navigation of an Aerial Robot in Sparse Forests

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 19; p. 4061
• Main Authors: Chiella, Antonio C. B., Machado, Henrique N., Teixeira, Bruno O. S., Pereira, Guilherme A. S.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 20.09.2019; MDPI
• Subjects: Adaptive algorithms; Algorithms; Attitude indicators; Autonomous navigation; Drones; Fields (mathematics); forest flight; Forests; Global navigation satellite system; Kalman filters; Localization; Motion control; motion planning; Navigation satellites; Navigation systems; Obstacle avoidance; Odometers; Reference systems; Robots; robust state estimation; sensor fusion; Sensors; surveillance; Trees; Unmanned vehicles; Vehicles; Velocity
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19194061

Autonomous navigation of unmanned vehicles in forests is a challenging task. In such environments, due to the canopies of the trees, information from Global Navigation Satellite Systems (GNSS) can be degraded or even unavailable. Also, because of the large number of obstacles, a previous detailed map of the environment is not practical. In this paper, we solve the complete navigation problem of an aerial robot in a sparse forest, where there is enough space for the flight and the GNSS signals can be sporadically detected. For localization, we propose a state estimator that merges information from GNSS, Attitude and Heading Reference Systems (AHRS), and odometry based on Light Detection and Ranging (LiDAR) sensors. In our LiDAR-based odometry solution, the trunks of the trees are used in a feature-based scan matching algorithm to estimate the relative movement of the vehicle. Our method employs a robust adaptive fusion algorithm based on the unscented Kalman filter. For motion control, we adopt a strategy that integrates a vector field, used to impose the main direction of the movement for the robot, with an optimal probabilistic planner, which is responsible for obstacle avoidance. Experiments with a quadrotor equipped with a planar LiDAR in an actual forest environment is used to illustrate the effectiveness of our approach.