Complex structure profile estimation and following with the GIRONA500 AUV

We present a seabed profile estimation and following method for surveying complex underwater structures in close proximity, enabling high-resolution data acquisition. The proposed method goes beyond traditional seabed following at a safe altitude, and exploits hovering-capable autonomous underwater vehicles (AUVs) equipped with a range sensing sonar to follow complex structure profiles in the vertical or horizontal plane in close proximity. The method maintains a local map representation that allows to deal with sensor delay and distortion due to the vehicle motion. An estimate of the local profile is obtained by means of linear regression. Two behavior-based control schemes which use the profile estimates are provided for horizontal and vertical profile following, respectively. The feasibility of the proposed method is demonstrated both in simulation and in pool trials using the GIRONA500 AUV.