Old, but New: Dealing with Legacy Systems in Defence

January 29, 2020

Legacy systems pose a number of challenges for defence OEMs. But with a bit of innovation, these are by no means insurmountable…

Legacy and Innovation: A Balancing Act

In the field of defence, where mission-critical systems are omnipresent, it is essential to consider the role of legacy systems – in other words, old hardware or software systems. In an age when defence technology is becoming more advanced and more streamlined, OEMs working in the defence sector should be aware of the need to build and adapt systems which are both effective and safe. There is also the concern of ensuring new components can be fully integrated into existing systems and having the ability to do this in an efficient and hassle-free way.

Fortunately, there are ways in which they can deal with the demands for flexibility of design and the repurposing of existing systems, as well as combat the risks that come with obsolete systems. Let’s take a look at some of these now…

Futureproof: Updating Legacy Systems

At some point systems will have run their course and need, in some way or another, to be updated. As a result, adding new components into existing systems becomes an attractive prospect, in terms of the ease with which this can be carried out compared with a complete system replacement, as well as the overall cost benefits.

One way legacy systems are having new life breathed into them is through virtualisation. The use of virtualisation by defence software manufacturers has enabled legacy hardware and software systems to be repurposed onto a single platform, combining them with newer software to improve their dynamism all the while cutting costs and giving greater flexibility when they need upgrading. In some instances, a separation kernel is used to enable a ‘patch’ to be applied to the existing system, ultimately enabling the legacy system to function without interruption while the new patch or layer runs its additional features.

Safety First: Keeping Legacy Systems Safe

So legacy systems can, more or less, be integrated with newer components. But another question then arises – how are these integrated software systems kept safe to use? One such way is through software-in-the-loop (SIL) testing.

This involves running embedded system components through a series of real-life scenarios to ensure each component of the system works as it should. As well as this, the source code is run through different scenarios and its behaviour checked against internationally recognised safety standards, such as the DO-178B, relevant to airborne mission-critical systems. As a result, OEMs can be assured that their embedded legacy system can safely operate.

Keeping It Together: Maintaining Legacy Systems

Coupled with ensuring these systems meet the security standards set for more modern systems, OEMs must also find ways to maintain legacy systems and, particularly, systems in which hardware components have become obsolete. In fact, possibly the main issue with legacy systems isn’t that the whole system is obsolete and unusable, but rather that certain parts of said system have reached the end of their lifecycle and are no longer effective or safe to use – meaning both OEMs and end users potentially have a lot of unpicking to do…

As an example, the Multi-Interface Computer Equipment (or MICE) on board the Portuguese Navy’s ‘Vasco da Gama’ class frigate had reached the stage in its product lifecycle whereby it had become obsolete, due to the discontinuation of its hardware components. Forming an integral part of the frigate’s data communication systems, it was necessary for the MICE to be replaced with COTS hardware, forming part of a wider solution developed by Critical. The hardware supplied significantly reduced the risk of further component obsolescence, the optimum solution for both OEM and end-user.

In the world of defence, there is no escaping the fact that a number of legacy systems exist, and that many OEMs need to provide solutions for obsolete systems. Yet with the right strategies and expertise in place, it is possible for legacy systems to be integrated into newer infrastructures, ensuring they remain fully functional while at the same time compliant with safety standards.

If you would like to know more about Critical's work on the defence sector click here.