Annotating SLAM data sets with Apriltag markers

This paper motivates and describes a methodology for annotating SLAM benchmark data sets where GPS or motion capture equipment is not viable. Ground truth camera pose measurements are obtained at the camera frame rate using surveyed Apriltag2 visual markers. The design of the marker plates, procedures for placing and positioning them, as well as the procedures for sensor track collection, are described. An estimate of the measurement accuracy is obtained by comparison with the Optitrack motion capture system, and the advantage over RTK-corrected GPS as a ground truth pose measurement source in certain environmental conditions is demonstrated experimentally.