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New weapon targets laser attackers

8 April 09 16:03 GMT

By Tom Symonds
BBC transport correspondent

The number of attacks on aircraft and helicopters using handheld laser pointers has risen from three in 2003, to 207 in 2008.

Could a new hand-held device to analyse these lasers help police track down offenders?

Officers are now using hand-held Laser Event Recorders (LER) to gather evidence when they are "attacked" from the ground. The LER is held up to the helicopter's window when the laser is first spotted.

The device, first adopted by the US Air Force, is a sophisticated digital camera which can detect laser radiation and take a picture of the attack.

It can also warn the police if the laser is powerful enough or close enough to cause physical damage to the eyes. There is a GPS receiver to record the location of the helicopter when attacked.

But the most useful function is the LER's ability to measure the wavelength of the laser. Often offenders claim it was not their laser that was used in the attack. But if the wavelengths match, the chances of a conviction increase.

The device will not actually catch a suspect, though. For that the police rely on the increasingly-sophisticated tracking systems fitted to their helicopters.

Greater Manchester Police says its MD902 Explorer helicopter, call sign India 99, is one of the most advanced in the world.

There are two observers on board. The rear observer has two large screens, one showing the image from the aircraft's camera, the other a moving map.

The camera uses thermal imaging to clearly show people and warm objects standing in gardens or on open ground. Even when the warm laser pointer is thrown into a bush it can often be seen from the air.

The rear observer can zoom in to show a glowing image of an offender, and then look at the moving map, where a cursor shows the spot on which the camera is focused.

It is an easy task to guide ground units in to make an arrest.

The helicopter can now both detect and track laser attacks. The police say arrests are now far more likely.

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