By combining two previously developed heatproof and waterproof wireless monitors with a newly developed technology, it may soon be possible to work a GPS through a debris-strewn, thick and smoky building. Working together, the three technologies could lead to a life-saving solution.
One device, the Geospatial Location Accountability and Navigation System for Emergency Responders (GLANSER), crams a microwave radio, a lightweight battery, and a suite of navigation devices into a tracking device the size of a paperback book. In the case of a firefighting incident, GLANSER’s signals come in and go out via a small, USB-powered base station plugged into a laptop on the truck. As firefighters move from room to room and floor to floor, the laptop display animates their every step.
A second device, the Physiological Health Assessment System for Emergency Responders (PHASER), can monitor a firefighter’s body temperature, blood pressure, and pulse, relaying these vitals back to the base station. If a firefighter falls or faints, fellow firefighters can race in, quickly find him, and bring him to safety, guided by GLANSER.
Like the first cordless phones, GLANSER and PHASER transmit at 900 MHz—a frequency that can penetrate walls, given a decent-sized transmitter. But because of their portable size, the transmitters are extremely modest. A wall, or in the case of a wildfire a strand of trees, could stop the signals unless relayed by routers.
That presents a challenge.
That is where a self-powered router comes into play. The Department of Homeland Security’s (DHS) Science and Technology Directorate (S&T) is developing a tiny throwaway router, measuring one inch square by ½ inch thick, that’s waterproof and heat-resistant up to 500° F. The Wireless Intelligent Sensor Platform for Emergency Responders (WISPER) contains a two-way digital radio, antenna, and 3-volt lithium cell.
Each firefighter enters a burning building with five routers loaded into a belt-mounted waterproof canister. If a firefighter steps behind concrete or beyond radio range, the base station orders his canister to drop a “breadcrumb.” The dropped routers arrange themselves into a network. If a router accidentally falls down a stairwell or firehosed under a couch, the WISPER network will automatically reconfigure.
To an embattled firefighter, a handful of these smart “breadcrumbs” could spell the difference between life and death.
To extract the most life from the router’s tiny battery, WISPER’s designers turned to a simple, low-power communications protocol, ZigBee. ZigBee is tortoise-slow by design; it trades speed for battery life, telegraphing no more than 100 kilobits per second (kbps)—a rate that’s more than 99 percent slower than WiFi.
“Throw in smoke, firehose mist, stairwells, and walls, and you’re down to maybe 10 kbps. But that’s fast enough to tell an incident commander the whereabouts (via GLANSER) and health (via PHASER) of every firefighter in the blaze,” said Jalal Mapar, WISPER’s project manager in S&T’s Infrastructure Protection and Disaster Management Division. “We’re not streaming video that needs a lot of bandwidth, just vital signs and coordinates.”
Oceanit Laboratories, Inc., of Honolulu, and the University of Virginia’s Department of Computer Science under an S&T Small Business Innovation Research (SBIR) program developed WISPER’s router, dispenser, and tiny USB base station.
In March 2011, Oceanit and UVA demonstrated WISPER for S&T at a FEMA office in Arlington, VA. Simulating a squad of firefighters, three router-toting researchers fanned out, dodging around corners, stepping down stairwells. In test after test, their signals stayed strong, even at a range of 150 feet.
Because the SBIR project is a success, S&T hopes a maker will step forward to produce the routers in volume. Once a commercial entity begins production, S&T’s Test & Evaluation and Standards Office will evaluate a sample product to ensure it meets the stated performance criteria and for consistency. S&T will also set industry standards so that other manufacturers will have a set of specifications for design and performance.