By using radio waves, a the Range-R allows law enforcement to detect movement inside your home.

At least 50 U.S. law enforcement agencies, including the FBI and U.S. Marshals Service, have secretly equipped their officers with radar devices that allow them to peer through the walls of houses to see if anyone is inside. This practice is raising concerns about the extent of government surveillance.

There was little notice to the courts and no public disclosure of when or how these radar systems would be used when they began deploying more than two years ago. The technology raises legal and privacy issues because the U.S. Supreme Court has stated that officers generally cannot use high-tech sensors to tell them about the inside of a person's house without obtaining a search warrant beforehand.

The Range-R device uses a Doppler radar system. Image via Digital Trends.

Called the Range-R, the device allows police to track people within a home using a Doppler radar system. Shaped similar to a stud finder, it can track movements, even if someone is taking a breath, up to a distance of 50 feet. Best suited for a hostage situation or a drug raid, the device could map out every person within a building and help police make calls on the best plan to breach.

According to the manufacturer of the Range-R, it’s able to penetrate wall materials that include poured concrete, concrete block, brick, wood, stucco glass, adobe, and dirt, but it cannot track movements through a sheet of metal material, and it has difficulty tracking people when used against a water-soaked wall.

The device doesn’t provide any visual images of the people within a home, and it’s unable to determine if a suspect is armed. The idea behind it is to give police verification that someone is inside the home, and to determine the location and activity level of that person.

To date, the U.S. Marshals Service has spent nearly $180,000 on these types of devices in the last three years.

Story via Digital Trends

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