PROCEEDINGS ARTICLE | October 13, 2014
Proc. SPIE. 9250, Electro-Optical Remote Sensing, Photonic Technologies, and Applications VIII; and Military Applications in Hyperspectral Imaging and High Spatial Resolution Sensing II
KEYWORDS: LIDAR, Calibration, Unmanned aerial vehicles, Clouds, Sensors, Reflectivity, Laser scanners, Data processing, 3D acquisition, Scanners
Small UAV:s (Unmanned Aerial Vehicles) are currently in an explosive technical development phase. The performance
of UAV-system components such as inertial navigation sensors, propulsion, control processors and algorithms are
gradually improving. Simultaneously, lidar technologies are continuously developing in terms of reliability, accuracy, as
well as speed of data collection, storage and processing. The lidar development towards miniature systems with high data
rates has, together with recent UAV development, a great potential for new three dimensional (3D) mapping capabilities.
Compared to lidar mapping from manned full-size aircraft a small unmanned aircraft can be cost efficient over small
areas and more flexible for deployment. An advantage with high resolution lidar compared to 3D mapping from passive
(multi angle) photogrammetry is the ability to penetrate through vegetation and detect partially obscured targets. Another
advantage is the ability to obtain 3D data over the whole survey area, without the limited performance of passive
photogrammetry in low contrast areas. The purpose of our work is to demonstrate 3D lidar mapping capability from a
small multirotor UAV. We present the first experimental results and the mechanical and electrical integration of the
Velodyne HDL-32E lidar on a six-rotor aircraft with a total weight of 7 kg. The rotating lidar is mounted at an angle of
20 degrees from the horizontal plane giving a vertical field-of-view of 10-50 degrees below the horizon in the aircraft
forward directions. For absolute positioning of the 3D data, accurate positioning and orientation of the lidar sensor is of
high importance. We evaluate the lidar data position accuracy both based on inertial navigation system (INS) data, and
on INS data combined with lidar data. The INS sensors consist of accelerometers, gyroscopes, GPS, magnetometers, and
a pressure sensor for altimetry. The lidar range resolution and accuracy is documented as well as the capability for target
surface reflectivity estimation based on measurements on calibration standards. Initial results of the general mapping
capability including the detection through partly obscured environments is demonstrated through field data collection
and analysis.
