1. INTRODUCTION A centralized command centre is the heart of combat management in any naval warship. Typically known as combat management system (CMS), it is a complex system that involves multiple elements that integrates different types of sensors, weapons, decoys, machines, communication, operational commanders, operators and also real-time tactical intelligence 1 . CMS systems have over the years improved steadily in their functionality and effectiveness when compared with the earlier systems like CAIO, BIUS, IPN-10, etc. Typical confguration of CMS for a modern war ship includes integration of electronic warfare, navigation, anti-submarine warfare (ASW), air-to-surface defense, air-to-air defence, helicopter/fghter aircraft control systems, etc. Sonar systems which are primarily responsible for all ASW operations form an important arm in the CMS confguration. Integrated sonar suite (ISS) is an integrated system of more than one type of sonar(s), all communicating and operating under a single display and control station and forms part of the ASW system 2 . The defence services release out quality requirements (QRs) to Defence Research & Development Organisation and companies for design and supply of new systems. QRs are in the form of specifcations which include operational, functional, maintenance and physical requirements. A preliminary solution design is already proposed by the user itself at this stage which may not meet the user requirement completely. The requirements arising out from other stake holders namely, the production partners and maintainers, etc are also to be considered 3 . The focus of this paper is to highlight the importance of ISS and suggest solutions from systems engineering discipline to capture the actual user requirements without compromising the classifed nature of the subject. Systems engineering is an interdisciplinary approach that integrates various disciplines and functional groups into a team effort forming a structured development process for complex systems 4,5 . It is holistic and stresses the importance of requirements study and analysis as one of the most important tasks to be carried out prior to undertaking any system development. In the paper, an outline introduction to ASW and CMS is followed by the basic capability requirements envisaged for an integrated Sonar suite. A brief description of the concept of operations (CONOPS) as applicable to ASW operations is given. A compliance matrix is generated to verify whether the requirement analysis study and the concept abstraction is complete and it meets the requirements of IEEE P 1220 standard. 2. INTEGRATED SONAR SUITE CONCEPT Concept of integrated sonar suite (ISS) is new and not common among navies of the world. ISS systems work primarily on data association and fusion thereby giving an integrated ASW picture. ISS is perceived to be fully automatic in operation for detection, classifcation and localization of different types of targets. Fire control solutions (FCS) work on passive and active sonar data to accurately fnd out the target range, course and speed and also classify the type of target. Data fusion and track correlation helps in track assignment in the case of crossing targets. ISS is aided by an integrated sonar Requirements Analysis of an Integrated Sonar Suite for Surface Ships : Systems Engineering Perspective Ajith Kumar K. * , Jomon George, and Jagathyraj V.P # Naval Physical and Oceanographic Laboratory, Defence Research & Development Organisation, Kochi, India # School of Management Studies, Cochin University of Science and Technology, Kochi, India * E-mail: ajithkumar@npol.drdo.in ABSTRACT Modern day combat warships are an integration of a large number of subsystems and components. Each of these systems communicates to a common combat management system. Anti-submarine warfare systems being an integral part of the combat management system, integration of multiple types of sonar systems or integrated sonar suite (ISS) offer complete solutions and tactical advantage against a potential threat. The operational requirements, the environment, the functional requirements and physical confguration of ISS are all discussed in this paper from the systems engineering point of view. Innovative methods are presented to capture the user requirements of ISS without compromising the classifed nature of the subject. Keywords: Anti-submarine warfare, sonar, requirements analysis, active sonar, passive sonar, classifcation, torpedo decoy, validation 366 Received 11 April 2013, revised 18 March 2014, online published 21 July 2014 Defence Science Journal, Vol. 64, No. 4, July 2014, pp. 366-370, DOI : 10.14429/dsj.64.4486  2014, DESIDOC