Imaging Sonar based AUV Localization and 3D Mapping using Image Sequences

This paper proposes a three-dimensional (3D) sonar mapping method and autonomous underwater vehicle (AUV) localization method using two-dimensional (2D) sonar image sequences of an imaging sonar. The 2D sonar image sequences are registered to generate a 2D mosaic sonar map. In this process, we can estimate the displacement and rotation relationship between the sonar image pairs, and use this to estimate the position of the AUV. A 3D point cloud is generated from 2D sonar image sequences. This method takes advantage of the mobility of the AUV to reconstruct the height information, and partially solves the ambiguity issues in the elevation angle of the imaging sonar. The height map is generated by accumulating the 3D point cloud. By fusing two maps, we can generate a 3D sonar map. We verified the proposed method by conducting field experiments. Three types of artificial reef on the seabed were scanned, and a 3D sonar map was created. In the process, the trajectory of the AUV was estimated and compared with the trajectory of the dead reckoning.