Terrain Reference Navigation Using SIFT Features in LiDAR Range-Based Data

Matthew T. Leines, John F. Raquet

Peer Reviewed

Abstract:	The use of GNSS in aiding navigation has become widespread in aircraft. The long term accuracy of INS are enhanced by frequent updates of the highly precise position estimations GNSS provide. Unfortunately, operational environments exist where constant signal or the requisite number of satellites are unavailable, significantly degraded, or intentionally denied. The motivation of this research is to explore sensors and techniques that will provide accurate navigation position updates in the absence of GNSS updates. A novel algorithm is proposed using scanning LiDAR range data, computer vision features, and a reference database to provide aircraft position estimations to update drifting INS estimates. The algorithm uses a single calibrated scanning LiDAR to sample the range and angle to the ground as an aircraft flies, forming a point cloud of coordinates. The point cloud is orthorectifed into a coordinate system common to a previously recorded reference of the flyover region. The point cloud is then interpolated into a digital elevation model of the ground. Range-based SIFT features are then extracted. Features common to both the collected and reference range images are selected using a SIFT descriptor search. Poorly matched features are filtered out using RANSAC outlier removal, and surviving features are projected back to their source coordinates in the original point cloud. The point cloud features are used to calculate a least squares correspondence transform that aligns the collected features to the reference features. Applying the correspondence that best aligns the ground features is then applied to the nominal aircraft position, creating a new position estimate. The algorithm was tested on legacy flight data and produces position estimates within 10 meters of truth using threshold conditions.
Published in:	Proceedings of the 2015 International Technical Meeting of The Institute of Navigation January 26 - 28, 2015 Laguna Cliffs Marriott Dana Point, California
Pages:	239 - 250
Cite this article:	Leines, Matthew T., Raquet, John F., "Terrain Reference Navigation Using SIFT Features in LiDAR Range-Based Data," Proceedings of the 2015 International Technical Meeting of The Institute of Navigation, Dana Point, California, January 2015, pp. 239-250.
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