A tracking system that works reliably inside buildings may help to pinpoint a first responder’s location, increasing safety for firefighters and other emergency personnel.

Recent demonstrations of NASA’s Jet Propulsion Laboratory’s POINTER (Precision Outdoor and Indoor Navigation and Tracking for Emergency Responders) have involved representatives from fire departments and the U.S. Department of Homeland Security.

Firefighting practice. Firefighting practice. Solving the indoor tracking dilemma involved both a technological and a mathematical breakthrough. Radio waves behave erratically indoors, bouncing off walls and failing to penetrate to basements. Instead, JPL researcher Darmindra Arumugam investigated quasistatic electromagnetic fields, which, unlike radio waves, have ranges of no more than a few hundred yards.

Using mathematics, he developed the theory, technique, and algorithms that can analyze both the electrical and the magnetic components of quasistatic fields. These algorithms are the key to being able to interpret the quasistatic fields and their signaling.

Quasistatic fields offer several advantages as the basis for building an indoor tracking system. They can move around walls, and they can be adjusted to different sizes and wavelengths. What's more, fields are stationary or change slowly enough to appear stationary. The fields can also detect the orientation of a device or a person.

This last feature is particularly important inside a smoke-filled structure, the researchers say. When a firefighter’s tracking device emits a quasistatic field, personnel outside the structure can tell if the firefighter is standing up, lying down, moving, or stationary.

Arumgam and his team built a tracking device that weighs less than half an ounce. Future miniaturization could produce a device that fits in a belt buckle.

POINTER’s future applications include search-and-rescue operations after natural disasters, such as tracking human and robotic searchers. The system could also monitor robots working in tunnels or under ice.

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