Tuesday, 02 September 2014
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Ahead of target: seeking the next generation of missiles

British and French engineers have been working together on missile technology that addresses the challenges of 21st century warfare.

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Source: MBDA

MBDA has developed a guidance system that gives an estimate of how likely a missile is to hit a target on its current path.

The fighter pilot has just a few seconds to make a decision as the enemy jet approaches. The missile is already on course to destroy the target and there’s an ever-increasing danger of a counter-attack if the pilot doesn’t change course. But the enemy could still use evasive manoeuvres to escape if the missile can’t maintain a link to the plane’s radar system and follow the target.

It’s in difficult situations like this that advanced technology can play a vital role; after all, staying one step ahead of the competition is even more important when your competition is trying to blow you up. Which is why the defence sectors in Britain and France have been working together over the last six years on a programme to produce the next generation of missile innovations.

The British and French defence ministries’ Materials and Components for Missiles Innovation and Technology Partnership (MCM-ITP) has linked 89 of the countries’ large defence contractors, SMEs and academic groups. Together, they’ve worked on a range of early-stage research projects covering every aspect of missile technology from materials to propulsion to sensors.

‘The main benefit [of MCM-ITP] has been that we are reaching out for innovation,’ said Mark Slater, future systems director for European missile manufacturer MBDA and the programme’s lead contractor. ‘We can always develop the next generation of what we’ve already got but we’ve been looking for ideas that will genuinely change things.’

For some of the more than 90 research projects in MCM-ITP, this means updating basic components that will enable breakthroughs to happen. For example, developing structural materials that can withstand the extreme conditions generated by hypersonic flight but are relatively cheap and easily sourced within Europe, or fitting wing structures with motors, actuators and flexible skins to allow them to morph and reduce drag at different phases of flight.

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The programme has produced several prototype components in new structural materials.

Alternatively it has meant creating new versions of old ideas that meet the challenges of 21st century warfare, such as warheads that explode and launch a projectile several meters from the target in order to defeat improved armour systems, which in turn were developed to protect against the improvised explosive devices (IEDs) now commonly used by insurgent forces.

But other projects have brought entirely new thinking to some of armed combat’s trickiest problems. Take the issue facing fighter pilots of when to leave a missile to reach its target without radar guidance. Working with French probability algorithm specialist firm Probayes, MBDA has developed a system known as Guidance in Uncertain Shooting Domains (GUS-D) that gives an estimate of how likely the missile is to hit its target on its current path.

‘At the moment, the pilot hasn’t got anything to help them with that,’ said MBDA senior operational analyst Toby Wheatley, who worked on the project. ‘It’s all based on previous experience and intuition on how well they think the enemy’s been doing. The idea is to give them some help. The pilots don’t want us to tell them what we think the enemy’s doing because if they do something slightly different then suddenly the attack doesn’t work. This just gives the pilot a tactical decision aid.’

This tactical aid could appear as a simple pie chart on the pilot’s display — the project team have built such a feature into a flight-simulator programme to demonstrate GUS-D. But the calculations behind it are much more complex. The system models the many trajectories an enemy plane could take based on its current movements and plots a missile path that intercepts the most trajectories, displaying the probability that the missile will successfully hit the target if the pilot cuts the navigational link at that point.

‘Our ultimate goal is to replace the way a traditional computer works by probabilistic computing.’

Emaaunel Mazer, Probayes

Probayes CEO Emmanuel Mazer said this technique of probabilistic reasoning was a general framework that could be applied to other scenarios. ‘Now we are considering how to use this for mission planning, because that is also a way to take into account uncertainty based on a future trajectory,’ he said. ‘Our ultimate goal is to replace the way a traditional computer works by probabilistic computing.’

Not all MCM-ITP projects have focused on introducing new capabilities and delivering higher performance: there’s also a drive to make missile technology more robust, according to MBDA director of future capability solutions Olivier Lucas. ‘For example, navigation systems already have better than one-meter accuracy,’ he said. ‘Do we need more than this? No. But there are conditions, such as the terrain, the weather and operational conditions where it doesn’t work.’

British SME Nottingham Scientific Ltd (NSL) has been helping MBDA address this issue by attempting to make GPS systems more accurate — and help protect them against jamming and spoofing attacks — using chip-scale atomic clocks. Conventional GPS receivers can take up to 30 seconds to re-establish their position if they lose the satellite link that guides them, because without this signal their clocks gradually drift away from the accurate time and then need to be recalibrated. GPS receivers with atomic clocks don’t experience this drift and so take just milliseconds to re-establish the link.

A more accurate clock could also enable the system to more easily spot the fake signals used in GPS spoofing attacks because the receiver can have greater confidence in its own timekeeping and so ignore attempts to re-calibrate it to an incorrect signal. Similarly, a highly accurate clock could allow a GPS system to analyse a jamming signal and introduce a filter to cancel it out.

To integrate the chip-scale atomic clock into the GPS system for a demonstration prototype, NSL had to design its own receiver technology because the project was on too small a scale to involve mass-market chip manufacturers. ‘The flexibility we can achieve is because we have full control of the receiver processing,’ said NSL’s principal navigation engineer, Yeqiu Ying. ‘A mass-market chipset has no interface open so it’s impossible to integrate this new chip-scale atomic clock with the GPS receiver to explore the advantages.’

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Source: MBDA

Another project has studied new versions of warheads that launch a secondary projectile to defeat the latest armour systems.

The other driver behind many of the MCM-ITP research projects is cost-reduction. For example, researchers from the University of Birmingham and French firm Microturbo have experimented
with additive-manufacturing techniques to produce missile engine parts that can cope with higher temperatures (and so improve fuel performance), at a lower cost than traditional manufacturing methods.

Another group, combining UK researchers from MBDA and Selex ES, is hoping to cut the cost of infrared sensors by applying an established technique known as wavefront coding. This could improve optical resolution across the broad temperature range missiles need to withstand without the need for numerous expensive lenses to readjust the sensor’s focus. The technique involves placing a translucent plate in front of the sensor that encodes the image by defocusing it in a known way. This can then be reversed by an algorithm but the process also spreads aberrations in the picture over numerous pixels, producing a clearer final image as a result.

‘What this is really looking at is can you have a much simpler optical design and achieve the same specification?’ said Chris Greenway, MBDA’s principal engineer on the project. ‘We’ve built a demonstrator that has only got two lenses optics in it, so it’s much cheaper, much lighter and much better for missile systems. And lighter is just as good as cheaper because it has a knock-on effect on the other components.’

With the first phase of the programme now coming to an end, the British and French governments are drawing up a new agreement to continue MCM-ITP for up to another six years, and MBDA is preparing to launch a new annual call for research proposals. The scheme has already produced dozens of promising concepts, studies and prototypes; next, the challenge will be determining whether they have strong enough application potential and, if so, developing them into commercial products.

But the programme’s leaders hope it will also encourage greater cooperation across the defence sector between the two partner countries, between small and large companies, and between government, industry and academia. ‘There’s a need to develop a common infrastructure rather than relying solely on our own,’ said Richard Brooks, programme delivery director at the UK MoD’s Defence Science and Technology Laboratory (DSTL). ‘The majority of future systems are expected to be delivered cooperatively with international partners or industry. The age of “government knows best” is over.’


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