This paper explores the state of the art on to methods to verify and validate navigation algorithms for autonomous surface ships. We perform a systematic mapping study to find research works published in the last 10 years proposing new algorithms for autonomous navigation and collision avoidance and we have extracted what verification and validation approaches have been applied on these algorithms. We observe that most research works use simulations to validate their algorithms. However, these simulations often involve just a few scenarios designed manually. This raises the question if the algorithms have been validated properly. To remedy this, we propose the use of a systematic scenario-based testing approach to validate navigation algorithms extensively.@en

In this article we present the state of the art in the field of autonomous surface ship navigation using machine learning. We discuss the main challenges towards the development of fully autonomous navigation systems with the International Regulations for Preventing Collisions at Sea (COLREGs). Finally, we propose two alternative approaches that are based on machine learning. Existing COLREGs-based navigation and collision avoidance algorithms are based on traditional search-based planning and optimization algorithms. We consider that these approaches are suitable when the problem space is defined completely and rigorously. However, experts believe that is not the case for COLREGs since it leaves many aspects open to the interpretation of the captain. For example, COLREGs expects that any collision avoidance action shall be taken with due regard to the observance of good seamanship, a concept not defined in the convention. Furthermore, many rules are defined using undefined concepts like safe distance, or keywords like early, or substantial, without giving any definition. COLREGs even allow for the rules to be broken to avoid an accident. Due to this, traditional planning approaches may not be able to handle complex scenarios that are underspecified according to COLREGs. An alternative is the use of machine learning (ML), reinforcement learning (RL) and imitation learning (IL) at the core of autonomous navigation systems. Machine learning is known to succeed and outperform traditional approaches specially in vaguely defined problem domains, where it is difficult, if not impossible, to create a full formal specification of the phenomenon under study. We consider this to be the case for COLREGs-based navigation and we conjecture that a ML-based navigation approach can outperform existing search-based and optimization algorithms.@en

A safety management system (SMS) is the common means used by organizations to assess organizational performance with respect to the safety and well-being of people, property and the natural ecosystem. A SMS provides confidence to diverse stakeholders that organizational safety is at an appropriate level and fulfils the applicable regulatory standards. As a multifaceted system for organizational safety assessment, ensurance and assurance, the evaluation of the design and operational use of SMS is a complex process. An evaluation needs to provide evidence about how well the design and operation of an SMS complies with applicable standards and how well the methods used in the SMS implementation support the organizational policies and practical work. In the maritime domain, SMS is broadly applied. However, there are few theoretically rooted SMS design approaches, and there is a lack of frameworks to evaluate how well the SMS is designed and how effectively it operates. This paper proposes an initial evaluation framework for the design and operational use of a maritime SMS design approach based on Systems-Theoretic Accident Model and Processes (STAMP), realist evaluation and Bayesian Networks. This framework is applied for a case study of vessel traffic services (VTS) Finland to test its relevance and ability to guide the SMS design. The experiences gained in the case study, and the related discussion on the framework, can guide further research in this area. Ultimately, the work can be used as a basis for developing maritime SMS auditing processes, based on specific theoretical and methodological approaches.

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