Abstract: A computer implemented method for guiding an under-actuated marine surface vessel in tracking a desired trajectory comprises expressing a predetermined vessel trajectory as a set of straight line segments, determining a desired current line segment, and determining the vessel's current position. A cross-track error and the derivative of the cross-track error are then determined. Next, a radius R of the line-of-sight (LOS) circle using a newly introduced exponential function is determined. Intersection points M and N between the LOS circle and the current desired line segment are determined. A desired heading angle is determined as the angle between the line of sight and a predetermined fixed reference line. A drift detection algorithm is built into the proposed guidance scheme to detect situations whereby the ship moves parallel to its desired trajectory for an extended period of time without being able to correct for the cross track error.

Abstract: A computer implemented method for guiding an under-actuated marine surface vessel in tracking a desired trajectory comprises expressing a predetermined vessel trajectory as a set of straight line segments, determining a desired current line segment, and determining the vessel's current position. A cross-track error and the derivative of the cross-track error are then determined. Next, a radius R of the line-of-sight (LOS) circle using a newly introduced exponential function is determined. Intersection points M and N between the LOS circle and the current desired line segment are determined. A desired heading angle is determined as the angle between the line of sight and a predetermined fixed reference line. A drift detection algorithm is built into the proposed guidance scheme to detect situations whereby the ship moves parallel to its desired trajectory for an extended period of time without being able to correct for the cross track error.