Deliverable D5.1 presents a draft standard for the interface between the Situation Awareness System (SAS) and the Autonomous Navigation System (ANS) onboard autonomous inland waterway vessels. Led by SINTEF Ocean, the work addresses one of the most fundamental technical challenges in autonomous shipping: establishing a common, standardised method for exchanging situation awareness information between perception systems and navigation systems.
Background and Motivation
For an autonomous vessel to navigate safely and independently, its onboard systems must be able to communicate with each other in a consistent and interoperable way. Today, no standardised interface exists for this exchange in the inland waterway domain. Without such a standard, every manufacturer must develop their own proprietary solution, raising costs and creating barriers for smaller companies entering the market. D5.1 directly addresses this gap by proposing the first structured interface standard of its kind for autonomous inland waterway navigation.
The work is part of Task 5.2 on Accelerating Uptake of Autonomy by Technical Standardisation, within Work Package 5 on realising the modal shift through business models, impacts, standards, and recommendations.
The SAS-ANS Interface
The deliverable proposes a clear separation of responsibilities between the two systems. The Situation Awareness System is responsible for the detection, classification, and state description of objects and environmental conditions encountered during navigation. The Autonomous Navigation System is responsible for traffic situation assessment, future-state prediction, route execution, and navigation decision-making. This separation enables a well-defined, modular interface that supports vendor-independent solutions.
The conceptual foundation of the interface is Endsley’s three-level model of situation awareness:
- Level 1 covers detection and classification of objects in the environment
- Level 2 describes the states and relationships of those objects
- Level 3 concerns projection and understanding of future traffic situations
The proposed interface standard focuses primarily on Levels 1 and 2, providing the ANS with the information it needs to carry out navigation-related analysis and decision-making.
The Data Model
The main technical contribution is a comprehensive conceptual data model expressed through UML class diagrams. The model defines standardised representations for:
- Dynamic objects: vessels, convoys, floating constructions, living beings, and floating obstacles
- Fixed objects and waterway infrastructure: bridges, locks, signs, buoys, and marks
- Environmental conditions: weather and water state observations
- Sound signals: horn signals and other acoustic communications used in inland navigation
The model is tailored specifically to inland waterway operations and aligns with established European standards including CEVNI (the European Code for Inland Waterways), Inland AIS (iAIS), and Inland Electronic Navigational Charts (iENC).
Key Challenges Addressed
One of the most difficult aspects of defining the interface is the classification of detected objects. Different standards, regulations, and operational systems apply different classification schemes, meaning the same physical object may be described differently depending on the source. The model addresses this by allowing a vessel to hold multiple characteristics simultaneously through attributes such as isMotorized, isHighSpeed, isSmallCraft, and isPropellingAConvoy, rather than relying on a single ship type code.
The deliverable also highlights that sound signals remain a significant challenge for autonomous navigation. Sound-based communication continues to play an important role in inland waterway navigation, particularly during reduced visibility, but automated sound recognition for autonomous systems requires further research.
Towards International Standardisation
The draft standard was presented at the ISO TC8/SC 26 Smart Shipping plenary meeting in Paris in June 2026. It will be submitted to IEC TC80/WG17 on Common Maritime Data Structure as a potential New Work Item, and discussed within the group’s ongoing activities on Maritime Autonomous Surface Ships (MASS). This follows directly from the consortium’s commitment to carry AUTOFLEX results beyond the project into international standardisation bodies.
Outlook
Future development of the standard will focus on uncertainty and confidence representation in sensor observations, richer geometric modelling aligned with the S-100 framework, integration with route exchange and maritime information services, and harmonisation of object classification across CEVNI, Inland AIS, Inland ENC, and MASS-related standards.
Partner Contributions
This deliverable was produced by contributions across the AUTOFLEX consortium:
SO – Lead author and co-authors: Marianne Hagaseth, Lars Andreas Lien Wennersberg, Håvard Nordahl
DST – Reviewer: Cyril Alias
