Qinetiq's spy in the sky

A technique astronomers use to search for gamma ray bursts in the depths of the Universe could be adapted to find terrorists responsible for car bombs in Iraq.

UK defence specialist

is developing coded aperture imaging, once reserved for astronomical purposes, for sensor systems to be used in high-altitude airships and unmanned air vehicles (UAVs).

The surveillance technology would detect and track large numbers of moving vehicles in dense urban areas 24 hours a day, from an altitude of 12 miles (20km).

Qinetiq is leading a team that recently secured a 33-month, £11m ($22m) contract from the

(DARPA) to continue its research on the technology for its Large Area Coverage Optical Search While Track and Engage (LACOSTE) programme.

Traditional imaging systems use lenses to focus light on to a detector, whereas coded aperture imaging replaces the lenses with a flat mask containing multiple pinholes (the coded aperture).

Astronomers use the technology to create images of non-visible radiation, such as gamma rays and X-rays. Points of light radiating from the cosmos pass through the pinholes of the mask and cast shadows onto the detector, resulting in multiple overlapping images. A built-in central processing unit then decodes this pattern and reconstructs the original image.