International   

To see through walls

James Randerson

London: A device that allows the police to see through walls could transform the way they deal with hostage situations, according to a technology company in Cambridge, England, that developed it.

The short-range radar machine allows the operator to track people moving inside a house and so decide, for example, where and when to storm the building. Rescue workers could also use it to see where earthquake survivors are trapped under rubble or in a burning building.

One option for the police and security services dealing with hostage situations is to drill through the wall of the building under siege and insert tiny cameras. This tactic was employed during the Iranian embassy siege in London in 1980. To cover the noise of drilling police planted bogus workmen outside with pneumatic drills.

But Prism 200, developed by Cambridge Consultants, gives a much more immediate picture of what is going on inside a building without potentially alerting occupants. It works by firing 100 radar pulses a second and listening in the short gaps between each one for echoes from inside. It has a range of 20 m.

If the room is large and empty then following a moving person using radar is relatively easy. But if the space is cluttered with chairs and desks, for example, the complicated set of reflections coming back becomes too difficult to interpret. Prism 200 works by filtering out radar returns from static objects and only displaying things that move.

Alan Wiltshire of Cambridge Consultants said: "We analyse all the reflections that we get back and we aim to record and remember the static things in the room so we can then track the moving things, which are presumably people."

© Guardian Newspapers Limited 2006

Printer friendly page  
Send this article to Friends by E-Mail

Stories in this Section

Confrontation across Bangladesh feared
BNP leaders acquitted
Gates, an agent of change: Bush
Envoy meets Suu Kyi
Kylie Minogue returns to the stage
To see through walls
Nuclear deal with India tops agenda, says White House
Hotline planned during Hu's visit

Copyright © 2006, The Hindu. Republication or redissemination of the contents of this screen are expressly prohibited without the written consent of The Hindu