For first responders such as firefighters, accurate locational tracking has been identified as a critical need. Knowing the exact location of individuals within an indoor structure (including the specific floor of a multi-floor building) during a search and rescue operation is vital to their safety. While GPS approaches are sufficient for many applications, it is impossible to use GPS to effectively locate people who are indoors or underground. During this project, the team will produce a marketable prototype that demonstrates indoor localization and tracking of first responders within 1-meter accuracy in a variety of buildings and structures without any pre-deployed infrastructure. The approach to indoor geolocation of individuals involves patented magneto-inertial technology and is based on low-cost MEMS sensors, expertly designed electronics, very precise calibration, and sophisticated dead reckoning and movement reconstruction algorithms. The solution will be optimized for real-world first responder use scenarios. In particular, the tracking device is a rugged but light-weight ankle-worn device and employs software which has been designed to be particularly intuitive and easy-to-use. The technology is protected by a portfolio of worldwide patents. The current version of the tracking device transmits data via Bluetooth to a smartphone. The smartphone then transmits (x,y,z) positions at a 1 Hz frequency to a back-end system via FirstNet, LTE/4G, or Wi-Fi. Any number of first responders can be tracked simultaneously. Real time visualization of positions and trajectories can be done remotely from any connected device, with only 3 second end-to-end latency. The device can also trigger “man-down” alerts when an individual’s lack of movement over a specified number of seconds is detected. Mid-term, a future device version will integrate the FirstNet/LTE/4G network connectivity and eliminate the need to carry a smartphone. The overall system, including the initialization of the devices and the software user interface, will be optimized for the use scenarios of interest, based upon direct first responder feedback. While mechanically robust, the solution will be accurate, easy-to-use, and cost-effective.