Firefighter location technology: What's available

There are a great number of challenges to building a system that will pinpoint a firefighter within a structure; here's a look at what's on the drawing board and on the market


Editor's note: This multi-part article will explore the problem, the technologies used, issues for agencies to consider, and some of the vendors and government programs that have addressed locating emergency responders inside buildings.

By John Facella

In Part I, we covered what the problem is for in-building location, what technologies can be applied, and some issues to consider including the inertial motion unit, the radio link and the display.

The federal government has had an interest in promoting research in this area, both for civilian applications (for firefighters and law enforcement SWAT), and for soldiers operating in urban environments. One of the military programs has been the Army RDECom CERDEC Dismounted Soldier Navigation project. 

A research project aimed at firefighters is a Department of Homeland Security Science and Technology Directorate, called GLANSER, which had several companies competing to find suitable technologies for solving this problem. A solution has not proven to be easy, despite years of research.

This project was won by a team headed by Honeywell and included TRX Systems and Argon ST. Their approach uses a Doppler radar velocimeter, inertial sensors, a 900-MHz ranging module, a pressure sensor and 900-MHz WiFi mesh radios for communications. A major design goal was to have 3-meter accuracy in both horizontal and vertical directions. 

In 2012, during trials with the North Las Vegas Metro FD, results of 20- to 30-minute scenarios were around 3-meter accuracy without using ranging, and 95 percent accuracy on what floor the responders were on.

Mantenna, Pointer
As a result of the tragic deaths of six Worcester, Mass. firefighters in December 1999, Worcester Polytechnic Institute, a local engineering university, spearheaded research into firefighter location.

11 Questions to ask when buying locator technology

1. How many responders can the system track?

2. Can the responders be labeled by seat position or badge number?

3. Can the system maintain accuracy in the various modes of travel used by firefighters including crawling, walking, running, both horizontally and moving up and down stairs or ladders?

4. Is the horizontal accuracy at least 3 meters (10 feet)?

5. Is the vertical accuracy at least 3 meters (10 feet or one floor)? 

6. Is this derived solely by a barometric pressure sensor, because fire and explosions will change the pressure inside a building?

7. Does the radio link use licensed frequencies that are less likely to be interfered with, or unlicensed frequencies? 

8. What is the distance from inside a building to the outside incident command post?

9. Is the equipment that the firefighter will carry resistant to water, heat, being dropped, and is it intrinsically safe rated for hazardous atmospheres?

10. Is it easy for responders to turn on and use?

11. Can the display software show the types of buildings in your jurisdiction, and is the 3D presentation easy to see where responders are?

Two professors, James Duckworth and David Cyganski, worked on their own technology, called the Mantenna. Additionally, for several years WPI held an indoor location workshop to allow collaboration and research results to be shared among companies.

A new project has recently started to pursue a different technical direction for indoor location. Called POINTER (Precision Outdoor and Indoor Navigation and Tracking Technology for Emergency Responders), it is a joint project between DHS ST and the NASA Jet Propulsion Laboratory

Instead of using radio frequencies, which have limitations because of signal reduction inside buildings and interference, POINTER uses low-frequency magnetic fields that can transmit signals through materials including wood, concrete, brick and steel rebar.

Responders wear a small transmitter that sends the signal to receivers at the incident command post. The device will work indoors or outdoors, above and below ground, and even underwater. 

John Price, the program manager for POINTER, reported that it completed Phase I, the proof of concept phase, in October. Once those results are in, Phase II work will begin and a prototype will be developed for testing with fire service personnel. The final prototype is expected by winter 2015.

On the market
Several companies have created products to solve indoor location. Here's a sample of what is available.

Naviseer's product uses inertial navigation, with the starting position established using GPS. The company's literature states that it can be used with any cellular or land mobile radio network. They state that location accuracy is 2 percent of the distance traveled in the horizontal direction, and vertical accuracy is 1.4 meters. Their display software allows an incident commander to extrude a building outline.

Australian company Navisens' software-only solution is designed to locate personnel within multi-level buildings, underground and outdoors.

Their motionDNA technology uses dead reckoning from a known starting point, and processes data from inertial sensors (accelerometers and gyroscopes) found inside mobile devices to provide a 3D navigation solution without external infrastructure. The information is wirelessly transmitted to a USB dongle connected to a remote computer. 

Globe’s Wearable Advanced Sensor Platform acts a tool to track the location of crews to improve situational awareness and potentially shorten the time needed to rescue a downed firefighter.

The WASP shirt is made from four-way stretch knit fabric that wicks moisture away and dries quickly. It is also durable to withstand normal firefighter activities and multiple washes.

The sensors are mounted on an adjustable strap embedded within a flame-resistant T-shirt. The TRX location union is worn on a belt at the waist and provides indoor location data in 3D. The Zephyr BioHarness 3 electronic module tracks heart rate, heart rate variability, respiration rate, activity levels, posture and other physiological factors.

The Next Nav solution depends on sending external timing signals to first responders via a terrestrial broadcast network that covers 93 percent of the U.S. population and can penetrate buildings. For safety, the signals are encrypted. 

Next Nav owns the network and uses a licensed spectrum in the 900 MHz location services band. They state that they can obtain a fix within 5 seconds after turning the unit on.

A barometric pressure sensor determines floor level. And during the FCC CSRIC tests (research into location accuracy using cell phones indoors to call 911), vertical accuracy was about 2 meters, according to GPS World.

Although TRX is one of the members of the Honeywell GLANSER team, it also has its own solution called NEON. NEON leverages work done on GLANSER, but also has its own unique technology, based on four patents, to deliver accurate indoor location with lower cost sensors. NEON has recently become available with the Motorola APX portable radio. 

The TRX navigation engine uses sensor fusion, ranging and inferred and known mapping to deliver accurate position. Sensors that are providing erroneous measurements or are not available are eliminated from the calculations. The system can optionally incorporate pre-installed anchor nodes to increase tracking precision in high-priority buildings.

As we've seen, in-building location is a difficult technical problem. Yet, multiple government and private research projects have been looking at this problem for some time. And with several vendors having products on the market, fire agencies should fully understand their pros and cons.  

About the author

John Facella is an independent consultant focused on fire service communications. He has over 30 years in the public safety wireless industry, including working for the two largest vendors. He is a member of the International Association of Fire Chiefs Communications Committee, the NPSTC Broadband EMS Working Group, and the National Fire Protection Association 1221 and 1802 committees. He has a BSEE from Georgia Tech, is a registered professional engineer in the United States and a chartered engineer in the United Kingdom. He is an active part-time firefighter and EMT with 30 years of experience in four states.

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