A regulatory-informed mixed-criticality ROS 2 reference architecture for maritime autonomous surface ships

Safety-critical autonomous systems operating under multiple regulatory regimes require architectures that translate obligations into traceable design constraints. Maritime Autonomous Surface Ships (MASS) exemplify this challenge: the International Maritime Organization (IMO) MASS Code, the International Regulations for Preventing Collisions at Sea (COLREGs), the European Union Artificial Intelligence Act, and the General Data Protection Regulation (GDPR) impose a union of overlapping, non-identical obligations on one platform without a unified implementation pathway. This paper presents a six-layer Robot Operating System 2 (ROS 2) reference architecture with dual-domain deployment for mixed-criticality MASS: non-safety perception, planning, and communication functions execute on Linux with PREEMPT_RT, whereas safety-critical fallback, arbitration, and actuator-interface functions run on a certified real-time operating system (RTOS) with certified Data Distribution Service (DDS) middleware. A regulatory-informed design methodology derives 48 traceable requirements from these frameworks and identifies cross-regulatory convergence patterns. Timing analysis indicates adequate design-stage margins, and UPPAAL model-checking of the four-state fallback state machine verifies core safety properties at model level; deployment-specific verification and operational validation remain future work. Three deployment phases span a 2026–2032 architectural deployment roadmap, and evaluation shows this is, among the works compared, the first reference architecture addressing all four frameworks within a single ROS 2 mixed-criticality design.