Global Alignment of a Multiple-Robot Photomosaic using Opto-Acoustic Constraints★ ★

Distributing the mapping problem over several vehicles provides the ability to survey an area in fewer time than with a single one. However, the communications required to maintain the vehicles in formation underwater are highly complex. We present a global alignment method for multi-AUV trajectory optimization. We take advantage of the acoustic messages passed between vehicles as well as of the further constraints posed by optical matches between images in some of the vehicles in the formation, both within a single robot and from different ones. By merging all these constraints, we can obtain both an optical georeferenced mosaic of the surveyed area and a joint optimization of the poses of the vehicles in the formation at each time. We present and discuss an application of the method on a real dataset collected within the MORPH EU-FP7 project.