Compact radar sees through walls

A new laptop sized radar unit has been developed that can enable police to detect if any people are in a room before they enter. The detector is called the Prism 200 and has been developed by a UK based technology company called Cambridge Consultants.

The device is held against a wall and produces instant 3D pictures of any activity in the room. The activity can be up to 20 metres from the device. Alan Wiltshire who helped develop the system said: “Police and other security forces want to know where people are inside a building before they have to force an entry. Being able to monitor activity within a room could make many situations less dangerous for both officers and suspects.”

Unlike other more traditional radar systems, the Prism 200 only capture images of moving objects. It takes a radar snapshot of the target room and by relating these images to the static background it can display any moving objects it has detected. The device can map an area in plan, side or in three dimensions. It can see through most materials, but metal beams may confuse the device.

Mr Wiltshire continued: “To commercialise this technology, we`ve talked to the spectrum of potential users and spent over a year refining the hardware and creating a man-machine interface that provides critical intelligence in an intuitive form. The result is a `switch on and go` unit that can instantly deliver high-level location information that helps tip the balance in favour of security operatives in a broad range of dangerous or time-critical situations.”

The radar antennas inside are arranged in such a way that Prism 200 has an extremely wide field of view: 120 degrees horizontally and 90 degrees vertically. When combined with the range of the radar, which may be user-selected in four steps up to 20 metres, this provides comprehensive coverage of interior spaces.

During operation, context-sensitive icons are displayed underneath the radar screen, to provide the operator with a one-touch means of changing key parameters such as the type of view, or range.

Prism 200 can be held against a wall or mounted on a tripod in a `stand off` position. The radar uses ultra-wide band (UWB) radar pulses that pass easily through standard building materials including bricks, blocks, concrete, timber, plaster, tiles etc. The radiated power is very low and the unit is inherently safe to use.

The ergonomics of the finished radar unit has been a key focus of the development process. The packaged system measures 210 x 300 x 450 mm and weighs 5.4 kg, which includes a lithium-ion battery pack that provides power for over three hours of continuous use.

The unit is easily carried and is designed for right and left-handed operators. When monitoring is started, the embedded system displays results within two seconds on the built-in 640 x 480 pixel colour display. Users can select colour schemes optimised for use in day or night situations.