The new Modular Open Systems Approach (MOSA) opens the doors to more innovative possibilities, as Paul Garnett explains.

The last couple of years have seen the US and UK military adopt open architectures as the preferred alternative to custom and proprietary electronics technology designs. The Commercial-off-the-Shelf (COTS) Initiative was first introduced in 1994 but, arguably, the real paradigm shift took place in 2019, when the U.S. DoD issued a memorandum mandating the use of the Modular Open Systems Approach (MOSA) for all weapons systems going forward and which was then made law, requiring all defence acquisition programs (MDAP) to be designed and developed using a MOSA.

According to the DoD, the use of MOSA solutions will “support a more rapid evolution of capabilities and technologies throughout the product life cycle through the use of architecture modularity, open systems standards, and appropriate business practices.” Among the MOSA-related open systems standards supported by COTS suppliers are the module, backplane and chassis standards defined by the VITA trade association, including 3U and 6U form factor OpenVPX (VITA 65) board and backplanes, the C5ISR Modular Open Suite of Standards (CMOSS), and the Sensor Open System Architecture (SOSA), currently working towards its rev. 1 release, sometime this year.

The move to MOSA is driven by the fact that each new capability or function that’s added to a platform is a complete system with its own subsystems, the duplication of physical and logical components increases complexity and costs. It’s an unsustainable approach, especially as platforms and budgets continue to shrink in size.

Interoperability is another significant issue with discrete, closed solutions. Closed solutions based on propriety technologies are designed to operate in isolation. As a result, they are very difficult and time- consuming to deploy on platforms where systems and people must work together to ensure personnel safety and mission success. They are also challenging to maintain and repair, especially if the vendor no longer supports it, or has gone out of business.

The use of MOSA components promises to shorten the path to field new technology to defeat emerging threats.

There are several open standards including: Open Mission Systems/Universal Command and Control Interface (OMS/UCI); Sensor Open Systems Architecture (SOSA); Future Airborne Capability Environment (FACE) and Vehicular Integration for C4ISR/EW Interoperability (VICTORY)

Modern efforts like the US Army’s VICTORY initiative and the UK’s Generic Vehicle Architecture (GVA) are helping to pave the way for a modern battlefield where system upgrades and modifications are quicker and less expensive.

The VICTORY specification was officially kicked off in 2010 by the US army and a consortium of defence and industry participants, including Curtiss-Wright, and promotes the use of open standard physical and logical interfaces between LRU subsystems on C4ISR/EW combat vehicles, mitigating the problems created by the ‘bolt-on’ approach to fielding equipment on military vehicles. Its implementation enables tactical wheeled vehicles and ground combat systems to recover lost space while reducing weight and saving power.

Additionally, it enables platform systems to share information and provide an integrated picture to the crews. What’s more, VICTORY provides an open architecture that enables platforms to accept future technologies without the need for significant redesign.

Above: The MPMC-9335 is a GVA-compliant 3 slot 3U OpenVPX- form factor rugged mission computer

Similar to VICTORY, GVA mandates open, modular, and scalable architectures in the design of land vehicles. Its standards apply to electronic and power infrastructures, mechanical interfaces, Human Machine Interfaces (HMI) and Health and Usage Monitoring Systems (HUMS). Where VICTORY specifically aims to provide an architecture for C4ISR/EW systems, GVA plays a wider role across the entire land vehicle platform.

The SOSA Technical Standard defines a common framework for transitioning sensor systems to an open systems architecture. With so many existing and emerging sensor systems to consider, the SOSA Consortium’s goal, to “allow flexibility in the selection and acquisition of sensors and subsystems that provide sensor data collection, processing, exploitation, communication, and related functions over the full life cycle of the C4ISR system,” is extremely important.

The SOSA standards initiative was initially developed as part of the FACE consortium. SOSA standards are compatible with FACE and OMS standards, and they leverage a number of VITA standards, including VITA 65, the OpenVPX standard that ensures interoperability among the COTS solutions that are used to create subsystems and systems.

Increased Interoperability

Modular and ruggedized COTS solutions provide the interoperability and flexibility that’s needed to rapidly integrate systems suitable for deployment in all application spaces.

CMOSS defines sharing mechanisms across software, hardware, and network layers. To define these mechanisms, CMOSS standards leverage the:

• VICTORY standards for network interoperability
• OpenVPX standard for combining cards in a common chassis
• Modular Open RF Architecture (MORA) standard for sharing RF resources
• FACE standard for software portability

There are discussions about including FACE in the VICTORY Shared Processing Unit definition.

With open standards-based COTS solutions, organisations are no longer forced to choose the proprietary offerings of a particular vendor. Instead, they have the freedom and flexibility to choose solutions from a far broader selection of vendors who are operating in a more competitive environment.

This more competitive landscape gives system developers access to a wider range of functionality combinations, availability timelines, and price points so they can keep programs on spec, on time, and on budget. They can also choose the optimal solution for the challenge at hand, rather than the only solution offered by the vendor to which they are tied.

In some cases, it will make sense from capability and cost perspectives to choose different solutions from different vendors and combine them. As long as each solution is designed and proven to meet the requirements in the relevant open standards, the risk in taking this approach is manageable. A multivendor strategy also allows defence and aerospace organisations to spread risk across multiple vendors.

Once the system is deployed, open standards compliance and interoperability enable faster, easier, and more frequent technology refresh cycles. Systems, cards, and components can simply be swapped out for updated versions. And, those updated versions don’t have to come from the original vendor, providing the opportunity to incorporate more sophisticated, SWaP-friendly, or cost-effective replacements.

Above: The VPX3-1260 is a rugged 3U OpenVPX single board computer based on the high-performance 9th Gen Intel “Coffee Lake Refresh” Xeon E-2276ME processor

On a similar theme, the ability to choose an appropriate solution from any vendor makes it possible to obtain and deploy the most up-to-date technology available to counter or overmatch a particular threat.

Finally, interoperability among system components increases operational availability levels because it’s much easier to ensure a reliable, long-term supply chain for spares and replacement parts. As a result, a total life cycle management approach can be adopted that reduces risks and increases the return on technology investments over the long term.

Lowering SWaP-C

Space inside a military vehicle is at a premium, and with such strict restrictions on what a military vehicle can fit inside, an interior cluttered with a myriad of systems, cables, and power supplies limits the amount of supplies that can be carried and hinders the in-vehicle experience.

This scenario has become increasingly common as technology has evolved, resulting from military vehicles being retrofitted with new or upgraded capabilities. Historically, adding functionality meant equipping a vehicle with a new standalone system. Each of these line replaceable units (LRUs) came with its own cabling and power supply, and integrating the LRU meant finding space to accommodate all this equipment. What’s more, finding the space to add a LRU comes down to more than just physical volume. The options for placing a new LRU may be limited by a platform’s mounts and harnesses, and the orientation of an LRU’s connectors can make finding the right space to accommodate the system a challenge.

Open standards like SOSA and CMOSS shift electronic systems away from an LRU model. Instead, a chassis can be installed to house LRMs, which can be replaced in order to upgrade functionality without changing the system’s physical footprint or peripherals. In addition, multiple functionalities can be incorporated into a single chassis, greatly reducing the number of boxes taking up space in a SWaP-constrained platform. Costs are also reduced since there are fewer pieces of equipment to maintain.

The establishment of MOSA for designing military systems has the potential to significantly change the landscape for COTS vendors and their customers. By lowering costs, fostering interoperability and competition and delivering cutting edge technologies to the battlefield faster, open standards promises to field critical new capabilities to the warfighter. Open architectures open the door to many new possibilities!