British boffins have developed a radar-based system that can see through walls and behind closed doors.

The system, devised by UK radar research specialist Cambridge Consultants (CCL) uses low-frequency radio pulses to penetrate walls up to 25cm thick. The proof-of-concept device built by CCL scans in the horizontal and vertical planes to build up a picture of objects within a 3D space beyond the wall.

The device can detect objects in a 5-10m range, and has a 120-degree field of view.

Signals reflected off objects behind the wall are detected and plotted on a simple plan of the area and an elevation view of the zone. Crude, perhaps, but enough to help "military personnel and emergency services in situations such as sieges, urban warfare, fire and rescue", the applications for which CCL is currently exploring the development of products based on the technique.

"This radar delivers the kind of high-level location information that could really tip the balance in favour of rescuers in a broad range of time-critical situations, like the aftermath of an earthquake or explosion, or a hostage situation," said CCL Associate Director Gordon Oswald.

According to CCL, the device emerged out of work it has done developing anti-collision systems for cars. That requires highly compact scanning devices, which is why the see-through-walls radar fits into a box the size of a notebook PC. ®