A Systems Engineering Approach For Security System Design Ian Alston & Simon Campbell Selex Galileo Ltd [email protected], [email protected] Abstract The number of application areas where security of resources, whether this is people, information or physical property, is ever increasing as our world culture changes and the potential threats to individuals rises. The threats that security systems need to mitigate against are becoming both more complex and also asymmetric. In association with this the number of emerging technologies that can be applied to security systems is also increasing, and together with current & changing threats, is resulting in a more complex system with many interacting and possibly distributed elements. This paper describes how Systems Engineering provides a methodical design approach enabling a design engineer to understand all the contributing factors and analysing the cost/performance trade of alternative solutions. It shows that security elements should no longer be an afterthought once the main system has been designed – but security should be tightly integrated with other system functions as a set of requirements or design constraints. Once these requirements and constraints have been determined the most appropriate security approach for a given situation can be determined. The paper then describes how the methodical approach is used to elaborate the solution based on the constraints, make appropriate design decisions to architect a solution and finally implement a system, using an integrated engineering discipline approach, that is fit for purpose. 1. Introduction Systems involving some element of security are increasingly becoming more complex and critical where failure of the whole system or the security aspects of the system would result in significant losses or disruption to individuals, organisations or countries. Examples include: – The inter-bank money transfer system – The national/international…