Automated Localization of UAV’s in GPS-Denied Indoor Construction Environments Using Fiducial Markers

Abstract

Unmanned Aerial Vehicles (UAVs) have opened a wide range of opportunities and applications in different sectors including construction. Such applications include: 3D mapping from 2D images and video footage, automated site inspection, and performance monitoring. All of the above-mentioned applications perform well outdoors where GPS is quite reliable for localization and navigation of UAV's. Indoor localization and consequently indoor navigation have remained relatively untapped, because GPS is not sufficiently reliable and accurate in indoor environments. This paper presents a method for localization of aerial vehicles in GPSdenied indoor construction environments. The proposed method employs AprilTags that are linked to previously known coordinates in the 3D building information model (BIM). Using cameras on-board the UAV and extracting the transformation from the tag to the camera's frame, the UAV can be localized on the site. It can then use the previously computed information for navigation between critical locations on construction sites. We use an experimental setup to verify and validate the proposed method by comparing with an indoor localization system as the ground truth. Results show that the proposed method is sufficiently accurate to perform indoor navigation. Moreover, the method does not intensify the complexity of the construction execution as the tags are simply printed and placed on available surfaces at the construction site.

IMU/Magnetometer/Barometer/Mass-Flow Sensor Integrated Indoor Quadrotor UAV Localization with Robust Velocity Updates

“…Algorithm Test Area Accuracy [6] Stereo camera SLAM 200 m * 300 m Meter level [7] Stereo camera, IMU SLAM 16 m * 16 m Meter level [8] Monocular camera, IMU Kernel adaptive filtering N/A Decimeter level [9] Monocular camera, optical flow sensor, IMU, barometer Indirect EKF 50 m * 20 m Meter level [10] Monocular camera, fiducial markers Relative pose identification 5 m * 5 m Decimeter level [11] RGB-D camera, IMU, ultrasonic, optical flow sensor…”

Indoor Localization of Quadcopters in Industrial Environment

“…Among the fiducial marker-based positioning solutions, the two most widely used are ArUco and AprilTag markers [7]. This technology is a map-based system, where the position of the markers is predefined [8]. Generally, increasing the camera resolution reduces the positioning error, but increases the computational demand.…”

Augmenting GPS with Geolocated Fiducials to Improve Accuracy for Mobile Robot Applications

“…Fiducials have previously been used in GPS-denied environments to augment odometry and inertial navigation systems (INS) to facilitate more accurate navigation through association with a ground-truth [17][18][19]. In contrast, we propose to use fiducials regions in non-GPS denied environments to improve GPS accuracy by reducing errors associated with time-variant variables for a short period of time.…”