U.S. Army Uses UWB to Track Trainees

By Mary Catherine O'Connor

Nov. 15, 2005—At a Military Operations in Urban Terrain (MOUT) training site at Fort Benning, Ga., the U.S. Army is using an ultra-wideband (UWB) RFID system from Denver-based Ubisense to track soldiers engaged in a mock village comprised of a number of multi-floor, cinderblock buildings.

"Within a MOUT environment, we need to track the soldiers while they train, primarily for lessons learned and after-action review. So as the soldiers perform whatever mission they're trying to accomplish, we are tracking their movements, their actions and their interactions with each other," says Eric Wagner, director of DSCI, a systems integrator and software development firm. DSCI installed the UWB system and operates it on behalf of the Army.

Eric Wagner, DSCI

Platoons of soldiers engage in combat training throughout the MOUT site, running drills of various operations, such as seizing buildings. As the soldiers move into and out of structures, they wear 900 MHz radios with GPS units, used to track their outdoor movements. They also wear Ubisense tags—Ubitags—so they can be tracked indoors. The 900 MHz radios then transmit the soldiers' GPS coordinates to RF receivers installed throughout the MOUT site.

Multiple interrogators, called Ubisensors, are located throughout the buildings, enabling the tracking of soldiers to within 1 foot of accuracy. This is accomplished by analyzing the strength of distance of the RF signals generated by the tags. UWB waveforms, however, can be read through walls, making it difficult at times to determine a soldier's precise location. To remedy this problem, infrared transmitters are mounted above doorways in order to pinpoint which room or hallway the soldier is in at any given time. Infrared receivers embedded in the soldier's vests send this data to his 900 MHz radio, which transmits it to the system's back-end software.

A Multiple Integrated Laser Engagement System (MILES) is also used in the combat training, with an infrared laser integrated into each soldier's rifle. Whenever a soldier is shot by a blank from such a weapon, a laser signal from the gun is transmitted to infrared sensors on his vest. This signal is encoded with an ID that coordinates with the person carrying the weapon. Video cameras, also mounted throughout the MOUT buildings, are used by commanding officers to watch the training drills.

All pertinent data for each soldier—GPS and Ubitag coordinates, MILES data (including where and when a soldier was shot) and the infrared locator data showing what room in a building he has entered or left—is sent to proprietary DSCI software, which creates position reports of the training exercise. DSCI uses the MILES data, the indoor and outdoor location data and the timestamps encoded into each of these data points to re-create the training sessions in a 3D virtual environment, akin to a video game. (DSCI also uses videotaped recordings of the drills when making these re-creations, to ensure accuracy to actual events.)

While watching these re-creations during post-training analysis, army personnel can change the course of events—such as having a soldier fire at a different time, or hold his fire completely—in order to generate a different outcome. Though DSCI is currently not using it, Ubisense also offers its own software that processes the Ubitag signals and displays them on a 3D interface.