The Use of Multi-Scale Fiducial Markers To Aid Takeoff and Landing Navigation by Rotorcraft

TL;DR

This paper demonstrates that multi-scale fiducial markers significantly enhance visual SLAM performance for rotorcraft takeoff and landing navigation, providing reliable pose estimation across various environmental conditions.

Contribution

It extends prior marker-based SLAM methods to nested marker layouts and evaluates their effectiveness in real-world rotorcraft operations.

Findings

Improved absolute trajectory accuracy with multi-scale markers

High fraction of estimated poses during semi-autonomous operations

Open-source dataset and SLAM implementation provided

Abstract

This paper quantifies the performance of visual SLAM that leverages multi-scale fiducial markers (i.e., artificial landmarks that can be detected at a wide range of distances) to show its potential for reliable takeoff and landing navigation in rotorcraft. Prior work has shown that square markers with a black-and-white pattern of grid cells can be used to improve the performance of visual SLAM with color cameras. We extend this prior work to allow nested marker layouts. We evaluate performance during semi-autonomous takeoff and landing operations in a variety of environmental conditions by a DJI Matrice 300 RTK rotorcraft with two FLIR Blackfly color cameras, using RTK GNSS to obtain ground truth pose estimates. Performance measures include absolute trajectory error and the fraction of the number of estimated poses to the total frame. We release all of our results -- our dataset and the code of the implementation of the visual SLAM with fiducial markers -- to the public as open-source.