## 1 Introduction
However, they cannot address dynamic changes to the ship's status such as blocked escape routes or muster stations by themselves because they lack the means to reroute the passengers, nor can they provide assistance to passengers that are unable to follow or comprehend the evacuation route. Visual guidance systems have been proposed [14; 15; 16] as a solution to the aforementioned limitations of the current evacuation infrastructure. Instead of using predefined evacuation charts or static signs, adaptive signs are installed and controlled through a centralized or distributed system, enabling the use of dynamic evacuation routes. Such a system can respond to an evolving situation and facilitate wayfinding by optimizing the route towards the muster points or embarkation decks while taking into account changes to the vessel's status, such as fire or partial flooding, or even passenger congestion. Visual guidance systems are a tangible improvement to the evacuation procedure, but they are still hindered by some of the same shortcoming associated with static signs. The presence of smoke onboard a ship can reduce visibility and affect their effectiveness, while they cannot be used by visually impaired passengers or provide personalized instructions to people requiring special attention due to moving disabilities or extreme stress and loss of situational awareness. A recent trend in emergency navigation is haptic navigation. Haptic navigation in indoor and outdoor spaces has been successfully demonstrated in the past [17; 18] targeting visually impaired people. Its unique advantages include the ability to deliver instructions on a per person basis, making the use of personalized navigation feasible. Furthermore, the guidance aids can be perceived from the broadest audience possible, delivering a system that is compatible with people facing various kinds of disabilities. As such, there is interest in applying haptic navigation in emergency situations. In [19], a haptic navigation system for navigation in underground mines is proposed. The system is based on a belt fitted with motors that produce vibrations to guide the user. A helmet equipped with vibrators for providing haptic navigation for first responders is proposed in [20], and a haptic navigation suit to navigate fire fighters out of hazardous environments is presented in [21]. These papers largely focus on trained individuals and are incorporated into existing equipment they are already familiar with. Furthermore, in recent years, indoor localization has benefited from the introduction of ultra-wideband radio technology, which provides improved accuracy over previous methods. Increased interest, along with dropping manufacturing costs, have produced ample implementations and standards with application in multiple industries [22; 23; 24; 25; 26]. This in turn leads to wider demand and even further price reductions, which makes it a prime candidate for a large-scale installation such as a cruise ship. Additionally, the increase in accuracy makes it suitable for use in constrained spaces. The authors believe that large passenger vessel evacuation procedures can benefit from the introduction of both indoor localization techniques as well as haptic navigation in the interest of preserving human life. One way to achieve this is by introducing the aforementioned technologies to the lifejackets which are required to be carried on all vessels. This approach targets largely untrained individuals with different physical properties across a large age group. Part of the challenge lies in adding functionality in existing equipment without compromising its primary usability and making the new features easy to use by individuals which have undertaken very minimal training with it. With all this in mind, a smart lifejacket was designed and implemented to help with the evacuation procedure and management in real time. It allows passengers to be directed to where they need to go during an evacuation under dynamic conditions, including blocked pathways and low-visibility conditions.