A Model-Based Systems Engineering Methodology to Support Early Phase Australian Off-the-Shelf Naval Ship Acquisitions

Abstract

A significant capability modernisation program and a wide-ranging review of Defence has meant that Australian naval ship acquisitions are now being undertaken with both increasing pace and increasing oversight. This comes at a time when naval ship acquisition has also swung away from the top-down approach of designing a ship to meet unique Australian requirements, to the strong preference to use off-the-shelf (OTS) ship designs from overseas. This situation creates a need for new approaches to support stakeholders with naval ship concept definition and acquisition methodologies (which include methods, tools, techniques, and processes) that can develop robust, defensible business cases for milestone decisions by government. This thesis addresses this important need through the construction of a structured Model-Based Systems Engineering (MBSE) methodology that combines ship design aspects with technical and trade-off analyses to enable evidence-based decision making by Defence and government on the preferred technical solution to a capability need. The research utilised the Constructive Research Approach to produce an artefact, the Middle-out Early-phase Above-the-line Naval Ship (MEANS) MBSE methodology. The methodology is focused on the Risk Mitigation and Requirements Setting Phase (early conceptual design) in the Australian Defence capability lifecycle as this is the key stage in determining the outcome of an acquisition project. Specifically, the MEANS MBSE methodology supports requirements definition through a concept and requirements exploration approach. This approach facilitates the definition of traceable, defensible requirements based on top-down requirements analysis and design space exploration, combined with a bottom-up market survey of the existing naval ship design space. Furthermore, the MEANS MBSE methodology uses multi-criteria decision making to provide robust evaluation of candidate OTS naval ship design options to select the preferred solution and identify design weaknesses, or relative deficiencies in each design. The MEANS MBSE methodology encourages design to take place in the modelling environment (as opposed to simply recording the design) and supports iterative “what-if” solution option analysis to evaluate proposed design changes. The research produced a validated, exemplar MBSE methodology, and a body of work on early-stage ship design approaches that together have much to offer Australian Defence for future ship acquisitions. Specifically, it extended the use of MBSE to establish, manage and guide early stage design and analysis activities, whilst simultaneously maintaining traceability to Defence strategic guidance and capability needs. This extension allows capability development stakeholders to demonstrate the links between strategy, design activities, and requirements definition, thereby making ‘contestability’ and Systems Engineering rigour inherent in the specification of the required naval ship. The novelty of the research arises from the novel synthesis of several proven system design and analysis methods into a bespoke MBSE methodology that provides unique functionality and assistance to ship acquisition stakeholders. The thesis is presented in a combined conventional narrative and publications format, with the publications upon which the body of the thesis is based included in the appendices.