The U.S. Department of Defense and Robotic Research LLC, announced an agreement worth about $16.5 million for personal tracker device attached to a soldier’s boot.

Through this deal the company is offering its warfighter localization sensor units tech, called WarLoc, to help better equip four deployed U.S. Army Brigade Combat Teams in different locations, a press release states. The first batch of WarLoc units have already been shipped to an Army team.

“We are deeply honored at having been chosen to supply the U.S. Army with our innovative WarLoc sensor units,” said Alberto Lacaze, president of Robotic Research. “WarLoc’s small-form factor and state-of-the-art capability to provide highly accurate localization and positional information in GPS-denied environments make this device a perfect fit for America’s forces tasked with defending our freedoms on the front lines.”

WarLoc provides superior localization and positioning data for teams of warfighters or first responders in GPS-denied environments, including underground facilities and inside buildings and mega-cities. The small WarLoc sensor mounts on footwear. Multiple systems work together to further enhance accuracy and maintain the localization of teams. The system is not only unique for its accuracy but also for its distributed nature that works well with challenging communication environments.

The algorithms are robust to communications failures and dropouts.

There are two variants of of the sensor — one mounted to the top of the foot (attached via the user’s shoelaces) and one mounted to the back of the heel (attached via straps).