Situation assessment - an essential functionality for resilient navigation systems

Critical infrastructures are essential lifelines for a wellfunctioning society, the competitiveness of the economy, and the social prosperity. One of the basic technological infrastructures of the global trade is the maritime transportation system with its wide range of sub-systems and their components as e.g. provided services and involved actors. The coordinated actions and concerted use of system components ensure the transport of goods and the mobility of population. Automatization, digitalization, networking, as well as autonomous operation are presently considered as suitable means to improve safety and enhance the efficiency of transportation. As a result, the ever more complex transportation systems and processes become more sensitive to existing and new emerging threats e.g. cyber attacks. That’s why the resilience of transportation and used systems have been moved in the focus of investigations and developments. However, a wide variety of proactive and reactive approaches are already used or are in discussion to enhance the reliable functioning of technological and carrying on socio-technical infrastructures. This also applies for ships’ and their navigation systems, whereby carriage requirements, performance standards and guidelines of the International Maritime Organisation specify what and how resilience principles should be implemented. This paper discusses the application of resilience engineering principles by shipside navigation systems and their effectiveness taking into account their mutual dependencies. Within this context the ship navigation system is considered as technological system (without human in the loop) as well as socio-technical system (with human in the loop). Case studies will illustrate under which conditions the application of resilience principles may result into an improvement of the operational reliability. Based on simulations it will be shown that the creation of added values by implementation of various resilience principles depends strongly on the applied, optimised system layout and its adaptability. For example, physical and functional redundancy is an approach used to overcome single failures or to reduce the reliance on individual technologies. The implementation of redundancy increases the system complexity (more sensors and sources), the mutual dependencies (controlling and decision making), and ultimately the number of potential threats. It will be shown that a sub-optimal implementation and utilisation of resilience principles may decrease the robustness of the shipside navigation system (technological view) as well as the reliability and adaptability of ship’s navigating system (socio-technical view). Both approaches require the monitoring of the system behaviour and system-relevant conditions to enable a condition-based controlling and management. This illustrates once again that monitoring is one of the cornerstones of resilience and is caused by the fact that the effectiveness of most resilience principles depends on availability and trustworthiness of situational information in relation to system status and environmental conditions, irrespective of whether the generation and use of the situational information is machine-made or human-made. Therefore monitoring has to be acknowledged as essential accompanying functionality to be considered in design and operation of resilient systems. For this purpose, the monitoring process has to be portrayed as functional process for the design of resilient navigation systems as well as influencing factor on the decision management and making of the ship navigating system