This article presents an experimental assessment of an Unmanned Surface Vehicle (USV) executing an approach behavior to several stationary targets in an obstacle field. A lattice-based trajectory planner is implemented with a priori knowledge of the vehicle characteristics. In parallel, a low-level controller is developed for the vehicle using a proportional control law. These systems are integrated on the USV control system using the Lightweight Communications and Marshalling (LCM) message passing system. Filtered vehicle-state information from onboard sensors is passed to the planner, which returns a least-cost, dynamically feasible trajectory for achieving the ascertained goal. The system was tested in a 750 m by 150 m area of the US Intracoastal Waterway in South Florida in the presence of wind and wave disturbances to characterize its effectiveness in a real-world scenario. The vehicle was able to replicate behavior predicted in simulations when navigating around obstacles. The approach distance to each target was favorably lower than the user-defined limit. Owing to the fact that the USV uses differential thrust for steering, the vehicle tracked the planned trajectories better at lower speeds.

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