Aerospace, Military & Defence

Commercial products’ military use evolution

By Pete Dorey, principal consultant at TÜV SÜD W

hen military and civilian requirements are found to be compatible, the pace of technological development

in the commercial market offers substantial opportunities for the smart acquisition of military capability. Funding for innovation within the commercial sector vastly outstrips budgets available to all but the most well-funded military research programmes. National defence programmes are focused on value for money, and there are obvious technological and cost benefits from integrating commercial off the shelf (COTS) components and final products into military systems.

In the military domain, electromagnetic interference may severely impair radio- communications and the functioning of other devices. Therefore, the use of commercial equipment in the military domain often requires additional electromagnetic considerations, to enhance compatibility with potentially sensitive military systems. For example, these include the introduction of barriers, such as shielded racks

12 July/August 2020

and filters, to reduce equipment susceptibility to harsher electromagnetic environments. Def Stan 59-411 Issue 3 was issued on 14 June 2019 and provides the foundation for ensuring EMC in defence procurement. TÜV SÜD was an editor within the original Def-Stan 59-411 EMC Working Group and has carried out development work in support of the Issue 3 update. Using the guidance in Def Stan 59-411 Part 1, a ‘gap analysis’ process can be used to determine whether the compliance evidence is more or less stringent than the Def Stan 59-411 test limit. Any shortfalls identified will help to specify the degree of additional protection that is required.

This gap analysis strategy can also be used to ensure that products specifically designed for military use still comply with relevant equipment directives for the commercial environment. Of course, this may introduce a cost-saving for testing a newly developed product. As this is a common issue, many manufacturers now offer suitable RF shielded racks and enclosures, within which the equipment can be housed without modification so that the validity of the CE marking for the commercial equipment can be preserved. Another consideration is the power supply element. As there are at least fifteen separate testing considerations to be considered, ensuring that a power supply is safe and appropriate for a particular product is a complicated process. Also, while domestic supplies operate at 50 Hz, the military can operate at 50, 60 or 400 Hz. This will affect the power components that must be selected when developing a product.

Components in Electronics

For commercial products, power quality tests must meet CE marking requirements. For military equipment the power quality tests are harsher, as for mission-critical defence equipment it is unacceptable for it to be upset by power surges. Also, rather than the consistency of electrical supplies generally experienced in the commercial world, the electrical power environment can also be very varied in naval vessels, military vehicles, and where soldiers in field operations are relying on batteries or generators.

The ability of military products to operate and survive against physical stresses such as extreme climate, temperature changes, vibration and shock, is paramount and therefore requires a rigorous testing regime. Testing requirements therefore significantly exceed normal commercial equipment operation.

Military standards, such as Def-Stan 00-35, help define the testing requirements for equipment, setting parameters according to the environment in which the equipment will be used. For example, land or sea environments, the platforms with which equipment may be combined, or the regions of the world in which equipment may be deployed. Understanding and testing to the correct operation in the right environments is therefore key to ensuring the successful operational deployment of equipment. As there are so many variables, extra unknown factors may come into play in the real world. For example, while you may have tested for a humid environment, you may not have anticipated that one particular user would leave the product in the sun for long periods of time,

before rain rapidly cools it. It is therefore possible to develop tests that combine environments to simulate such “real life” scenarios, reproducing these physical environments in the laboratory under repeatable conditions to simulate the actual environment.

BS EN 60068-2 is a general standard that gives guidance on how to conduct environmental testing. Meanwhile, the defence sector has its own specific requirements that sit alongside this, such as the USA military environmental testing standard, MIL-STD-810. However, as BS EN 60068 is not market or product-specific, it is a useful tool to tailor environmental tests specific to each individual product need.

For the military domain, there are obvious benefits from integrating COTS components and final products into military systems, particularly as product development budgets in the commercial marketplace are generally much greater than most military research programmes. Such smart acquisition of capability therefore offers great potential to reduce the transfer time of innovative technologies into useful military products. However, commercial equipment manufacturers may assume that taking a step into the military market is a complex and costly issue. Indeed, some may over-complicate the test process, resulting in unnecessary duplication of compliance-testing. Testing time and cost can be minimised by using gap analysis between Defence Standards and the commercial standards.

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