Cobham develops more accurate landmine detector

The daunting task of clearing landmines that litter the fields of an estimated 62 countries in the world is being supported with a new technical solution developed by a British engineering consultancy.

An engineering team led by David Daniels of Cobham Technical Services has developed a new kind of mine detector, dubbed Minehound, which promises to spot deadly, explosive items with fewer false alarms than other comparable technologies on the market.

The product, which is currently being sold through German metal-detector manufacturer Vallon, was recently nominated for a Royal Academy of Engineering MacRobert Award.

Daniels said the Minehound detector combines a ground-penetrating radar with a high-performance metal detector to increase detection performance. The current standard devices for mine detection are metal detectors, he said, but in many situations there can be 100 to 200 false alarms for each real mine found.

‘De-miners actually spend an awful lot of time excavating things that are quite benign because they can’t get any discrimination for the kind of target they’re interested in,’ he said.

The Minehound dual-detection system is reported to reduce the false alarm rate by a factor of up to seven.

The International Committee of the Red Cross estimates that 60-100 million mines are in place in 62 countries, causing 800 deaths each month.

According to figures presented by Cobham Technical Services, detecting and removing these mines averages £1m/km2.

The consultancy believes that much of this cost is owed to high number of false alarms from metal detectors and sees dual-sensor technology enabling nearly 33 pert cent more land to be cleared within existing budgets.

Daniels explained that the Minehound’s dual sensors work by initially using the metal detector to sense whether any metal is present and then using the ground-penetrating radar to provide further information about the suspected object.

‘The radar sends out a pulse but at very high centre frequency,’ he said. ’The pulse duration is in the order of one nanosecond. That pulse then travels through the ground and backscatters from the mine.’

A precision receiver detects those weak signals and a specially designed processing software converts the information and presents it to the operator as an audio tone, he said, adding that the entire sampling process takes no more than 15 nanoseconds.

Daniels said the size and depth of the target can be determined by listening to the audio tone. ‘We basically use a musical scale,’ he said. ‘We can provide the operator with information on the depth of the target and, depending on the size, we can make the volume of the sound larger or smaller.’

The entire detection system consumes approximately 5W of power and can operate continuously for eight to 10 hours on a single charge.

Cobham Technical Services is still researching further improvements to the technology. Daniels said that one goal is to make the mine-detecting process more autonomous by mounting systems onto the front of remotely controlled vehicles – meaning that operators may no longer need to walk potentially explosive-laden fields again.