Development of a sonar system to assist firefighter navigation in low-visibility high temperature environments.

Firefighters routinely have to go through buildings with reduced visibility due to smoke. Moving through even the simplest apartment building can become a perilous task when you remove visual sensing, and introduce fires, toxic gasses and extremely high temperatures. While a number of tools, both low and high tech, exist to aid firefighters, none of them are perfectly able to solve this problem. This thesis proposes using sonar to supplement those tools, and documents the development of a flame-penetrating sonar. To the authors knowledge, no previous effort has been made to develop sonar for firefighting applications. Traditional ultrasonic range finders were found unable to penetrate flames, and thus a pulse-compression based sonar is presented here. A prototype sonar is developed to allow experimental testing of this technique. A number of experiments were conducted to understand the limitations of this device. This sonar was able to overcome the scattering of the flame, and even detect the extents of the flame. A number of applications of this technology can be imagined other than assisting firefighters. Military personnel, or anyone else needing to navigate obscured environments could use this technology. Other applications could be two-dimensional and three-dimensional temperature field reconstruction for industrial applications. The author believes combination sensors using sonar, thermal-imaging, global positioning system, dead reckoning, etc, are the only way to solve the problem of firefighter navigation.