Autonomous COLREGS Modes and Velocity Functions

Abstract

This paper concerns an implementation of an autonomy system for unmanned surface vessels operating in accordance with the Coast Guard Collision Regulations (COLREGS). The autonomy system is implemented by associating a dedicated ownship behavior module for each contact for collision avoidance. For each behavior, a mode determination is made based on the COLREGS rules, ownship position and trajectory, and the contact position and trajectory. Based on the mode, an appropriate objective function is generated, over the set of possible ownship maneuvers, to bias the vehicle in accordance with the COLREGS. The focus on this paper is solely on (a) the mode determination algorithms, (b) the requisite ownship and contact terms regarding position, trajectory and relative position utilized in the mode determination algorithms, and (c) the form and equations used in making the objective functions associated with each mode.