Sim2Sea: Sim-to-Real Policy Transfer for Maritime Vessel Navigation in Congested Waters
This work provides a solution for reliable sim-to-real policy transfer for autonomous maritime vessel navigation, which is a significant problem for the shipping and logistics industry, as well as defense applications. It represents an incremental step in improving the robustness and safety of autonomous systems.
This paper addresses the challenge of autonomous navigation for maritime vessels in congested waters, which is critical for real-world applications but hindered by complex interactions and environmental uncertainties. The authors propose Sim2Sea, a framework that enables zero-shot transfer of policies trained purely in simulation to a real 17-ton unmanned vessel operating in congested waters, demonstrating faster convergence and safer trajectories compared to baselines in simulation.
Autonomous navigation in congested maritime environments is a critical capability for a wide range of real-world applications. However, it remains an unresolved challenge due to complex vessel interactions and significant environmental uncertainties. Existing methods often fail in practical deployment due to a substantial sim-to-real gap, which stems from imprecise simulation, inadequate situational awareness, and unsafe exploration strategies. To address these, we propose \textbf{Sim2Sea}, a comprehensive framework designed to bridge simulation and real-world execution. Sim2Sea advances in three key aspects. First, we develop a GPU-accelerated parallel simulator for scalable and accurate maritime scenario simulation. Second, we design a dual-stream spatiotemporal policy that handles complex dynamics and multi-modal perception, augmented with a velocity-obstacle-guided action masking mechanism to ensure safe and efficient exploration. Finally, a targeted domain randomization scheme helps bridge the sim-to-real gap. Simulation results demonstrate that our method achieves faster convergence and safer trajectories than established baselines. In addition, our policy trained purely in simulation successfully transfers zero-shot to a 17-ton unmanned vessel operating in real-world congested waters. These results validate the effectiveness of Sim2Sea in achieving reliable sim-to-real transfer for practical autonomous maritime navigation.