The US Federal Bureau of Investigation (FBI) plans to buy radar technology that can detect people on the other side of walls, whether they are moving around, standing still or even lying down. The technology could be used to find people trapped in disaster wreckage, for example, or locate individuals evading law enforcement.
The idea of using radar 鈥� a system that uses radio waves reflecting off objects to determine their location 鈥� in this way has been around for at least 20 to 30 years, says at University College London. But he describes the field tests with this new system as 鈥渋mpressive鈥� in demonstrating how 鈥渢hey鈥檝e solved a lot of the engineering problems that you need to solve if you鈥檝e got something that people are going to use for real鈥�.
The FBI declined to comment on its intent to purchase this technology, called the system, from the company Maxentric Technologies, which was detailed in a 3 April published in a US government database. The company has developed and tested the radar system with the help of the US Department of Homeland Security (DHS).
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First responders tested the radar prototype on both indoor and exterior walls at the company鈥檚 California facility on 18 October 2022, according to a DHS . The agency later organised another test in Washington DC in September 2023 and scheduled additional testing with federal, state and law enforcement agencies in late 2024. DHS and the company did not respond to requests for comment.
The lunchbox-size radar system works by being leaned directly against a wall while attached to a standing tripod, with users standing about 1.5 metres away and controlling the system with a tablet or phone app. The app displays radar results as a multicoloured map, similar to a heat map,聽with human icons designating the likely locations of people.
The radar system鈥檚 8-gigahertz bandwidth can deliver high-resolution images, 鈥渨hich allows you to discriminate between individual people鈥�, says Griffiths. The ability of the electromagnetic signals from such radar systems to penetrate walls depends on the material. 鈥淭hick brick walls are going to be less transparent than light wooden walls,鈥� he says.
The system can also distinguish between human motions and repetitive mechanical ones, such as ceiling fans or air conditioning systems, says , who researched similar radar technology while at the Massachusetts Institute of Technology. He describes the technology as being best suited for monitoring a fixed area inside a building, and says it may require multiple radar systems to cover larger areas.
During testing, officials said the technology was intuitive and easy to use. But they also described difficulties and inconsistencies in the radar鈥檚 ability to determine the exact number and location of people in a room because of 鈥渕issed detections and false positives鈥�. An published by DHS in late 2023聽indicated that the agency is making further improvements to the technology to increase its precision and consistency.
