Soldiers on target

Civilian casualties in Iraq and Afghanistan could be reduced in the future with smaller missiles and better targeting technology.

So claim the British developers of a new inertial measurement unit (IMU), an electronic device that collects information on a craft’s velocity and position using accelerometers, and direction using gyroscopes.

Atlantic Inertial Systems, based in Plymouth, has unveiled a new IMU the size of a bottle top.

Ian Scaysbrook, chief engineer of military sensors for Atlantic Inertial Systems, said the small size of the device, called MinIM, opens up an array of new application areas.

These applications, he said, could include small 70mm missiles that are better targeted and less likely to affect civilians in war zones.

Atlantic Inertial Systems has patented another use for the device dubbed non-GPS man navigation.

Scaysbrook said the device would be part of a brigade-management system so commanding officers could track where soldiers have travelled in areas where GPS is unavailable.

‘This device has the sort of size and power consumption that could be conceivably built and strapped to a soldier’s leg,’ he said.

‘Or it could also be built into his boot or onto his rifle.’

The MinIM is a follow up to Atlantic Inertial Systems’ previous IMU, called SiIMU02, a hockey puck-sized device installed in the US Army’s Excalibur, a 155mm extended-range guided artillery shell currently in use in Iraq and Afghanistan.

With SiIMU02, Scaysbrook said the Excalibur has an accuracy of 2m – meaning it never misses a target by more than that amount.

He claimed the accuracy of MinIM is just as good and the only difference is its much smaller size.

Scaysbrook said Atlantic Inertial Systems was able to achieve this miniaturisation by using electrostatic gyroscopes.

Both the SiIMU02 and MinIM include three gyroscopes and three accelerometers each made of silicon, he explained.

The difference is the gyroscope in the SiIMU02 is a silicon ring carrying a current that oscillates in a magnetic field.

Scaysbrook said the silicon gyroscope ring in the MinIM oscillates through an electrostatic field so it does not use a magnet.

‘By going to capacitive technology you can reduce the size of the ring down to 3mm,’ he said.

‘It’s less than half the size in radius so therefore the area is a quarter of the size.’

Scaysbrook said manufacturing is also easier and less expensive.

‘You don’t have a magnet so you can do all the build up of the gyro in the silicon,’ he added.

‘It becomes purely silicon manufacturing rather than having a robot actually building this thing up as a pile of pieces that all get glued together.’

Siobhan Wagner