MONITORING SYSTEM

A method for designing a secondary sub-system for monitoring the condition of a platform is disclosed. The platform can include one or more primary sub-systems. The method can include identifying stakeholders of the platform, capturing information requirements of the stakeholders, determining data requirements corresponding to the information requirements, defining a sensor array comprising sensors suitable for providing output signals relating to condition characteristics of the one or more primary sub-systems, and defining procedures for converting the output signals from the sensor array to the data requirements, thereby to fulfil the information requirements of the stakeholders. The method can be implemented using a design tool having a graphical user interface with a hierarchical layer structure.