Guided Search: Exploring Technological Solutions for Interior Navigation in the Structural Fire Environment

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Kenneth Pravetz


Firefighters operate in zero visibility, high heat, and toxic environments. Firefighters work in unfamiliar structures and must quickly and efficiently search these structures for lost victims. These challenges lead many firefighters to lose situational and spatial awareness and then get lost. The National Institute of Health and Occupational Safety Firefighter’s line-of-duty death investigations point to this loss of awareness as a contributing factor to many firefighter deaths. Firefighters inside buildings lose their ability to share their locations with incident commanders and would-be rescuers. There is an opportunity to improve survivability by providing a navigation system for the structural fire environment.
Navigation is the process of moving from one point to another. Technology has advanced in this area from navigating by stars using the sextant to the Global Positioning System (GPS) using satellites. Navigational aids have improved travel around the world, and technology can guide the way. Unfortunately, GPS does not function indoors because devices cannot communicate with satellites. Navigation is a large part of searching for victims and locating the source of a fire. The problem is that firefighters get lost while searching in thick smoke and darkness. The fire service is seeking a reliable system that will provide the ability for firefighters to navigate an unknown structure to improve the mission of saving lives.
This thesis was designed to answer the following question: What technology has the highest potential to be adopted to provide interior navigation for firefighters in a structural fire environment? The duration of the program at the Center for Homeland Defense and Security limited the project, so there was not enough time to conduct actual tests or trials. Therefore, an exploratory method was used to evaluate previous research done in other industries to develop indoor navigation systems. The literature review identified that existing radio frequency technology might provide a reliable system to support interior navigation. This thesis explored the scholarly literature, and the knowledge gained helped define the technologies examined in this thesis. An evaluation of the fire problem was conducted to estimate the annual costs of fire losses in the U.S. The information for each technology was then applied to the mission model canvas (MMC). In the book Business Model Generation: A Handbook for Visionaries, Alexander Osterwalder and Yves Pigneur describe a canvas as a tool to help innovators visualize information and identify unknowns. The MMC compares alternatives from a public sector perspective.
Indoor navigation is a complex challenge. Leonardo Ramirez et al. point out that firefighting intervention makes interior navigation solutions more challenging to design. As quoted in Karimi’s work, Prashant Krishnamurthy claims, “Building an entirely new infrastructure for positioning in indoor areas would incur substantial cost in a variety of ways.” For this reason, many researchers have tested the highly dispersed existing radio-frequency technology found in most structures. Wireless fidelity (Wi-Fi), Bluetooth, and radio frequency identification are all possible ways to define location inside a structure. Hui Liu explains that there are many ways to identify a location: physical location, symbolic location, or absolute location. Each definition is useful in different situations. When sharing a position with another individual, both must be using the same reference system for the transfer of information to be helpful.
Indoor navigation systems use triangulation, fingerprinting, and proximity to measure the distance from a known point to calculate a precise location. Triangulation uses measurements from multiple sources to identify the angles and determine a location. Fingerprinting matches the measurements to previously identified reference points. Proximity also uses reference points, and the closest source defines the relative position.
All of the technologies have different advantages and disadvantages. Wi-Fi is a technology that is in most public spaces in the United States. Wireless access points supply the service, and these broadcast a service set identifier to define the network. This broadcast signal speed between the wireless access point and the receiver is measured to calculate a location. Bluetooth technology has evolved to be more reliable and more powerful. A Bluetooth system consists of positioning servers and receivers (or beacons). Bluetooth proximity systems have been successfully installed in specific retailers and large commercial spaces. In these systems, a user can open an application on a mobile device to gather information about one’s proximal space and the items in the area. Radio-frequency identification (RFID) systems utilize tags and receivers, and these devices typically have less power than other technologies. RFID is not a standard technology in mobile devices, but many RFID tracking systems have been developed to find items with RFID tags. The terrestrial transmitter system functions differently. It uses transmitters engineered to cover a metropolitan area. These transmitters operate just like GPS and leverage GPS hardware to define the location and assist in navigation accurately. This system works indoors and can account for changes in elevation to assist in high-rise operations. Each of these technologies may serve as a feasible solution to the problem.
Augmented reality and spectral image fusion are two alternative technologies that may assist in maintaining spatial awareness. Augmented reality is a complex solution that requires a known location, travel direction, and direction of the user’s gaze. To function correctly, the user will need a camera, display, and gyroscope, not to mention a system that defines his location. Spectral edge image fusion is a technology that combines multiple camera lenses into one view to enhance the user’s view of items. This technology can leverage the deployment of the fire service thermal image cameras.
The thesis identified the cost of loss of life and property to fire in the United States. Fires have a significant impact on the U.S. economy—in the form of direct and indirect costs. This expenditure equals 1.9 percent of the gross domestic product. The majority of fires occur in residential structures, and this is also where the majority of deaths occur. The National Fire Protection Agency defines the value of statistical life as $9.4 million, which leads to an annual cost of human life lost to fire in the United States of $43 billion per year.
The MMC was used to identify the business potential for each technology. The value proposition helps innovators solve customer problems. The innovator must be able to solve the problem and have a viable business opportunity. Indoor navigation will involve many key partners and key activities. Ron Adner refers to this as an innovation ecosystem. He goes on to point out that this type of interdependence brings additional development risk. The final aspect of the MMC is mission achievement, which defines whether all other parts of the canvas will result in success.
Out of all of the technologies evaluated, spectral image fusion is going to be the solution to support the mission and help with navigation. It is likely to be adopted and will improve survival. Spectral image fusion is an incremental step as this technology will not provide navigation but will enhance spatial and situational awareness. The terrestrial transmitters are a longer-term option that will require innovation before they will be a viable solution. The other technologies—Wi-Fi, Bluetooth, RFID, and augmented reality—all present too many challenges to achieve the mission and have a low potential for being adopted.
Incorporating additional training into the national standards for a firefighter to maintain situational and spatial awareness is an alternative finding that can support technology solutions.
Finally, the thesis discovered that there is a need for additional testing and trials, including some in real live-fire situations, to test the potential for many of these systems.

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