GLANSER is a "cocktail solution" of several components fused together to provide an estimate of the location of an emergency responder whether inside or outside a building. GPS, IMU, a 900 MHz ranging and communications radio, Doppler radar, a magnetometer, motion model technology, and an altimeter all are combined to fit into a 2"x4"x6" electronic device called a Geospatial Locator Unit (GLU) that a responder wears.

This combination of sensors works in harmony. So, when a GPS signal is not available or RF ranges to the base station are not optimal, other signals are exploited in an innovative manner. With the help of the onboard Kalman filter, all measurements are processed to compute the responder's location to within a couple of meters. GLANSER's mobile ad-hoc mesh network is then used to continuously transmit the location information to a base station at the command post.

Vehicle-installed base station nodes similarly participate as peers in the mesh network, helping to enhance the positioning performance of the GLU. The concept of operation requires no set-up time other than turning the nodes on as the GLANSER system initializes itself en route to the scene of the incident.

When no GPS signal is available or RF ranging is low, an Inertial Measurement Unit (IMU), aided by Doppler, provides an effective means for estimating location. While motion-classification and motion-model techniques also are employed as aiding devices, the Dopplers provide robustness, especially during firefighter common modes of motion, such as crawling, duck walking or even loitering.

Additionally, autonomous map-generation and map-matching algorithms help constrain inertial drift by automatically determining the location and orientation of building features and sending corrections to those who revisit them. Thus, by reducing the magnitude of IMU errors, this technology enables the use of low-cost IMUs.

Read the main story, "New technology improves firefighter location" to learn about the DHS' new GLANSER technology.

Jalal Mapar is program manager for the U.S. Department of Homeland Security's Science and Technology Directorate.