In an emergency, knowing exactly where a first responder is can mean the difference between life and death. When a firefighter in a burning building fails to check in, how does the commander know where to look for them?

Public safety agencies face daily challenges in finding first responders inside large buildings. Yet there are no reliable methods for tracking first responders in these types of environments.

So NIST has partnered with Indiana University’s RedLab to develop technologies to address this. The goal of the First Responder Smart Tracking (FRST) Challenge is to create prototype devices that track first responders indoors. In the five years since the challenge launched, teams from across the world have developed dozens of novel solutions—some of which have been turned into commercial products.

NIST is working with teams to ensure that their solutions meet the needs of public safety agencies, such as encouraging participants to make products affordable enough for first-responder budgets.

GPS and the challenge of indoor navigation

The widespread adoption of GPS has mostly solved the difficulty of navigating outdoors. But GPS is unreliable indoors.

Tracking a location with GPS requires a device to sense signals from satellites surrounding the planet. Layers of building material can block or interfere with those signals.

This problem is even worse for high-rise buildings. They have more building material and are often built in dense, urban environments. In these scenarios, it’s even more critical for an incident commander to know exactly where their personnel are located.

We asked participants to create wearable devices that are:
• Easy to wear and carry
• Able to track a responder accurately through complex buildings and long paths
• Capable of communicating back to the base station
• Tough enough to survive a firefighting environment

The challenge

Verifying the accuracy of these systems is a significant challenge. That’s why we used the dots facility, an indoor localization test bed developed by Nader Moayeri on the NIST campus in Gaithersburg, Maryland, to test these systems.

This system involves more than 2,000 carefully documented points (marked with stickers) inside and outside NIST buildings. These points, or the “dots,” as we call them, are spread throughout our campus. The dots are in hallways, stairwells, offices, laboratories, machine shops, underground tunnels, warehouses and many other spaces. The variety and size of locations available to us make the NIST campus an ideal place to conduct these experiments.

One of thousands of “dots” on NIST’s campus in Gaithersburg, Maryland. As part of a challenge to test approaches to locating first responders, participants had to precisely locate the dots. Credit: R. Wilson/NIST

In May 2025, NIST put the competitors’ systems through their paces. Teams attached their systems to participants who navigated a series of scavenger hunt-like missions. They had to find hundreds of individual points. Each team used its system to estimate the position of each dot along its course. NIST scientists and engineers then analyzed the data against the known position of each dot to rigorously judge the accuracy of each system.

Keeping first responders safe

If first responders are going to use this technology, we have to build confidence in it and show that it’s been thoroughly tested. That’s what we can do as the nation’s metrology lab.

Confidence in the technology depends on rigorous testing, a particular strength of NIST expertise. Credit: R. Wilson/NIST

Although the FRST Competition is officially winding down, we’ll continue to work with partners on developing indoor tracking innovations for first responders.

We recently built the Public Safety Immersive Test Center in Boulder, Colorado, to conduct research on first-responder user experience and location-based service technologies. For example, these researchers are testing algorithms to track first responders in buildings.

Competitions like this encourage private-sector innovations in public safety. Without them, companies wouldn’t have the financial incentive to invest in creating these types of products.

I’m proud to be part of this project because I can focus NIST’s measurement science expertise on technologies that will play an important role in protecting emergency personnel when they respond to a crisis. It’s a privilege to help first responders get their jobs done and get home safely.

Published Feb. 4, 2026, in the NIST Taking Measure blog.