In outdoor locations, firefighters and emergency responders can use GPS technology to track one another. Indoor environments like high-rises and steel-reinforced structures, however, frequently block radio signals. With the development of POINTER (Precision Outdoor and Indoor Navigation and Tracking for Emergency Responders), Darmindra Arumugam has addressed the sensing challenge, and provided a potentially game-changing tool for search and rescue teams.
NASA Tech Briefs: What kinds of sensing technology will benefit firefighters?
Darmindra Arumugam: Firefighters don’t have devices that permit them to locate themselves on a map. They don’t know how to navigate themselves out sometimes, because the building can be on fire with a lot of smoke. Firefighter leads also want to have orientation sensing – the ability to monitor whether a person is underground, crawling slowly, or immobilized, for example. Responders need a technique that enables accurate sensing of position and orientation in 3D space, using a small device.
NTB: What’s unique about the POINTER technology?
Arumugam: One of the only ways to get information from the inside of a building is to use electromagnetic fields or waves. Camera-based systems will not be able to penetrate through layers of walls. Electromagnetic waves, used in radars and GPS, combine electric and magnetic field propagations, which reflect off walls and limit penetration in places like steel-reinforced buildings.
POINTER exploits the “quasistatic” region of the electromagnetic wave, where the electric and magnetic fields can be decoupled. When you decouple the fields, the wave phenomenon disappears. You end up having either a static magnetic field or a static electric field. We call these quasi-stationary fields.
When the electric and magnetic field is decoupled, there is no energy transport over distances. POINTER uses the field’s magnetic component to easily penetrate through buildings and enable very accurate position and orientation sensing, because most things in nature are not magnetic.
NTB: Can you describe the components of the system?
Arumugam: To generate and detect these magneto-quasistatic fields, you need to use very small coils, and couple those to some kind of electronics. A current is generated in this coil, transforming the waveforms and creating a magneto-quasistatic field in the air. The receiving side is very similar. You use coils to sense the field. Specialized electronics mapped to the coil receive those waveforms generated in the circuit. [The receiver] could be a mobile device far away, outside the building.
NTB: How does the firefighter carry the device?
Arumugam: The systems today are backpack-sized, which are on the order of about 4 x 4 x 9 inches. POINTER, over the next two years, has a mandate to reduce the size of the device to a cellphone-like technology, in order for firefighters and first responders to place it on a belt buckle.
In August of 2016, POINTER was successfully demonstrated to the Department of Homeland Security (DHS) Science and Technology Directorate, which has funded its development. To download this interview as a podcast, click here.