Recieved 12 July 2010, Revised 31 August 2010, Published Online 6 January 2011 1. INTRODUCTION Since any damage to a ship can adversely affect impact critical systems and mission capabilities, all crew members must work in close cooperation. Effective communication among the crew members engaged in a task is extremely important. With this in mind, primary or secondary means of onboard a ship communication do not guarantee effective communication in emergency situations. From a commanding officers point of view, the ability to recognise an emergency situation and make expeditious and appropriate decisions is very important; however, to make such decisions, commanding officers need to be immediately aware himself about each of the crew member on duty, that is crew members location and role, as well as the overall condition of the emergency situation. If a commander knows the location and role of each crew member and is able to communicate orders to them in real time, the situation can more easily be controlled. Such a scenario can be most conveniently and cost-effectively achieved by tracking crew members with a sensor network based on wireless communication systems; however, most wireless communication devices use the GHz frequency range, and therein, face several challenges when deployed in steel- structured naval vessels. 2. CREW MEMBERS LOCATION AND ROLE RECOGNITION IN AN EMERGENCY Crew members are repeatedly trained to react and follow specific damage control scenarios. However, most accidents occur suddenly and do not provide crew member an opportunity to use their training. Moreover, the judgment of the commanding officer is often inhibited by limited information about the state of the situation 1 . In emergency training tests, effective ship-wide communication is critical to establishing an integrated damage-control effort. By knowing each crew members location and role, ship recoverability can be enhanced, as shown in Fig. 1, which depicts a simple flow chart that outlines actions for damage control using crew member location information. To recognise each crew members location and to control emergency, US Navy uses specific equipment such as wireless fire fighting ensemble which equipped with low-light infrared imaging, video and high quality voice communications 2 . However this kind of equipment is big, heavy, and expensive. When one considers wireless sensor network for location recognition on land based system, he finds that various studies have been performed. However, warships are commonly constructed from steel, making the application of wireless communication in the GHz frequency range difficult. Furthermore, this specific environment limits the usability of other types of wireless sensor networks. ZigBee tags were considered in this experiment to track each crew members location and role due to their small size and durability. ZigBee tags communicate less data compared to Bluetooth or Wi-Fi, but enough to transmit role code of each crew member. In addition, ZigBee tags require less power compared to other technologies, making Location Tracking of Moving Crew Members for Effective Damage Control in an Emergency Hee Jin Kang * , Dongkon Lee * , Jong Gye Shin ** , and Beom Jin Park * * Maritime & Ocean Engineering Research Institute/KORDI, Korea ** Seoul National University, Korea Email: ray5117@moeri.re.kr, dklee@moeri.re.kr, jgshin@snu.or.kr, baracude@moeri.re.kr ABSTRACT In an emergency, the commanding officer may have limited information, and crew members may behave differently compared to how they behaved during training. In an emergency situation, if the commanding officer is aware of each crew members location and role in that situation, one can disseminate orders expeditiously and precisely. To realise a faster and more precise dissemination of orders through better awareness of each crew members location and role, real-time crew member tracking is needed. The technical feasibility of a real time crew-tracking system based on a wireless sensor network has been studied, with the intent to improve effective commanding in an emergency. Location tracking was achieved using instrumentation consisting of ZigBee tags, routers, and gateways, which were used to record the location and role data of moving crew members on a full-scale ship. Keywords: Wireless sensor network, ZigBee tags, location recognition, moving crew, communications, emergency situation handling, damage control SHORT COMMUNICATION Defence Science Journal, Vol. 61, No. 1, January 2011, pp. 57-61 Ó 2011, DESIDOC 57 , DOI: 10.14429/dsj.61.503