Experimental validation of robust non-linear state observers for autonomous surface vehicles equipped with position sensors.

This paper describes the application and experimental validation of two different extended state observers for autonomous surface vehicles. Only the vessel position and orientation are assumed to be measured, being both estimators able to recover, not only the velocities, but also the so-called lumped generalised disturbance, which groups both environmental disturbances and nonlinear/unmodelled vessel dynamics. The experimental platform and the open-loop experiments performed to assess and validate the performance of both estimators are described. The experimental results confirm the prospects given by their previously published simulation results, though some room for improvement is detected in the estimation of the state dynamics.