December marks the 10th anniversary of the Worcester (Mass.) Cold Storage warehouse fire that killed six firefighters. Since the tragedy, researchers at the Worcester Polytechnic Institute have worked on a prototype model that uses myriad wireless technologies to track firefighters on scene. WPI recently announced the prototype is in the testing phase and—once it is proven—will be available to the market in approximately two years.

“The six firefighters were only a few feet from an exit and they had no idea where they were,” said WPI’s Jim Duckworth, associate professor in electrical and computer engineering and co-principle investigator on the project, about the fire. “The fact that the commanders had no idea where they were means that they couldn’t extract them. That sad lost of life led our department head to push for a firefighter tracking program.”

The institute was awarded nearly $3 million in Department of Justice a National Institute of Justice to develop a firefighter tracking system. The goal was to develop a commercial system that can pinpoint a person's location in three dimensions to within about a foot, have a range of 2,000 feet and track up to 100 people simultaneously—displaying the position and path of each individual on a screen at the incident command center, Duckworth said.

Researchers determined they needed a locator system that included transmitters worn by firefighters and receiver units placed outside the building to pick up those signals. They first looked at existing technologies, including GPS. GPS works great outdoors but is not appropriate for indoors because “it doesn’t have the correct single strength and suffers from multi-path where the radio signals bounce off all the metal surfaces,” Duckworth said.

“There was nothing out there we could currently use so we went back to basics to develop our own radio system with our own special frequency components,” he said. “We knew our ideas would probably have to be modified, so we built it on a software-defined radio where there’s flexibility on how you modify your signals. If we encounter stumbling blocks, we didn’t have to trash the existing prototypes; we just re-programmed it with a combination of software and firmware.”

Duckworth said the prototype system consists of hardware and software components. Each firefighter wears a small cell phone-sized radio transmitter inside their turnout gear that transmits a special set of tones. Tones are transmitted from the firefighter though the walls and the floors of the building to the other component—the receiver unit outside the building. The receiver units have antennas and pick up the signals being transmitted by the firefighters and are designed eventually to be embedded in fire trucks. The third component is the base station that picks up all the signals from the receiver antennas.

“Then through signal processing algorithms it determines in three dimensions where exactly the firefighters are in the building and, in real-time, data are sent the command’s computer screen so they can see exactly where all of the staff are at any given time,” Duckworth said.

Mapping software loaded on the laptop lets commanders track firefighters, Duckworth said. In addition, WPI received in 2006 an additional $1 million from FEMA to expand the system. FEMA wanted the institute to combine location tracking with physiological monitoring because the No. 1 cause of firefighter fatalities are actually stress-related heart attacks, he said. The WPI tracking system has been integrated with a physiological monitoring shirt with embedded sensors that determine heart rate that Foster-Miller developed.

“We then added that information to our location tracking and then on the incident commander screen we developed this GUI map that shows location tracking as well as the vital signs of each firefighter,” Duckworth said.

Researchers are still working on ruggedizing the transmitters worn by firefighters.

“Our prototypes are fragile… we couldn’t drop them from a great height and they wouldn’t survive high-pressure water in an incident,” Duckworth said. “At the moment, we are trying to prove whether we have the technology to solve the problem and then ruggedization of system would follow.”

Duckworth said receivers worn by firefighters may cost $500 to $800. Receivers embedded on the fire trucks would be around $1000 to $2000, he said.