MOSA, SOSA & More: The Rise of Mil/Aero Open Standards

On the modern battlefield, computing power is just as important as firepower. The demand for signal processing is rapidly increasing, with everything from electronic warfare systems to sensor fusion requiring massive leaps in capabilities.

Traditional proprietary architectures can no longer keep pace with these demands. Instead, the defence sector is turning toward open standards and modular architectures. The U.S. Department of Defence has mandated this approach through initiatives like the MOSA and SOSA.

While open standards promise greater interoperability, faster technology insertion, and reduced lifecycle costs, their implementation requires careful navigation of technical complexities and integration challenges.

Key Defence Industry Initiatives

The defence sector’s push toward open standards is being driven by four major initiatives:

MOSA (Modular Open Systems Approach) is a DoD-mandated strategy that promotes the use of modular and interoperable components in defence systems. It encourages architectures where subsystems can be upgraded or replaced independently, reducing costs and improving adaptability. This approach contrasts with traditional proprietary “black box” designs, which limit flexibility and vendor choice.

SOSA (Sensor Open Systems Architecture) establishes a standardised framework for integrating military sensor and processing systems. It ensures that components, such as radar modules, signal processors, and electronic warfare systems, can interoperate regardless of the manufacturer.

FACE (Future Airborne Capability Environment) standardises how avionics software operates across different airborne platforms. By defining a common software environment, FACE reduces development costs and enables greater reuse of mission applications across various aircraft.

VICTORY (Vehicular Integration for C4ISR/EW Interoperability) addresses integration challenges in military vehicles by standardising networked interfaces for communication, power distribution, and data sharing. Instead of each new system requiring its own dedicated connections, VICTORY leverages Ethernet-based networking to allow components—such as radios, sensors, and GPS units—to share resources efficiently, reducing redundancy and complexity.

Technical Standards at Work

These initiatives are implemented through several key technical standards, illustrating the evolution of military computing architectures. This evolution can be seen in the transition from VME to VPX to OpenVPX standards.

The original VME standard, which originated in the early 1980s and is exemplified by a range of products from companies like Sundance, served defence needs for decades.

Figure 1: Sundance’s range of VME boards and TIM modules.

The SMT328, introduced in the late 1990s, demonstrates the final iteration of the standard, i.e. VME64 with a 64-bit backplane that could support up to four TIM-40 Modules. This Module standard was the frontrunner for the many newly released “Systems-on-Modules” on the market. TIM-40 provided a mixture of TI’s Floating-Point DSPs, FPGAs, and DAQs. However, VME’s limited bandwidth was inadequate for modern defense applications requiring high-speed sensor processing and data fusion, so a new standard was required.

Figure 2: Sundance’s SMT328 is a classic VME board.

This limitation led to the development of VPX , which replaced VME’s parallel bus architecture with high-speed serial communications. The transition to VPX enabled significantly higher throughput and better system integration. The modern variation is called OpenVPX, which became VITA 65 in 2019 and furthered these capabilities by defining standardised profiles that ensure interoperability between different vendors’ products.

Etion Create’s VF365 illustrates the capabilities enabled by OpenVPX. This 3U module integrates an Altera Arria 10 SoC FPGA with dual-core ARM processors and TI’s KeyStone Octo-Core DSP technology delivers the processing power needed for applications like radar signal processing and electronic warfare. Its architecture supports high-speed serial interfaces, multiple memory types (DDR3, QDRII+), and standardised VITA FMC mezzanine sites for I/O flexibility.

OpenVPX modules come in two primary form factors: 3U and 6U. The 3U form factor (like the VF365) measures approximately 100x160mm, offering a compact solution with low thermal resistance, ideal for space-constrained applications. The larger 6U form factor (233x160mm) provides more real estate for complex systems requiring additional processing elements or I/O capabilities.

Figure 3: Etion Create’s VF365 showcases the capabilities of OpenVPX.

The OpenVPX concept is a constantly evolving system, and one of the later additions is VITA46.11-2022, an upgrade to the IPMC (Intelligent Platform Management Controller). This embedded controller monitors and manages system health, power consumption, and thermal conditions, ensuring the reliable operation of OpenVPX-based systems in demanding military environments. It plays a critical role, and several vendors, like Hybrid-DSP , offer sources and development environments for board and system integrations to maintain compatibility.

Figure 4: Example of IPMC control for OpenVPX.

OpenVPX and its related specifications are maintained by VITA (VMEbus International Trade Association). This non-profit organisation develops open standards for embedded computing systems in defence, aerospace, industrial, and other high-reliability applications. Its work ensures consistency across platforms and vendors, making OpenVPX a natural fit for initiatives like MOSA and SOSA.

Real-World Implementation Challenges

While the benefits of open standards are clear, implementation brings several challenges:

• Ensuring true interoperability between different vendors’ products requires rigorous testing and validation
• Security considerations must be balanced with openness, particularly for mission-critical systems
• Standards must evolve to incorporate new technologies while maintaining backward compatibility
• Industry resistance can slow adoption, particularly when proprietary solutions offer competitive advantages

Bridging the Gap

Success with open standards requires partners who understand the technical specifications and their practical application. Sundance and Etion’s approach demonstrates this philosophy, delivering advanced signal-processing capabilities via OpenVPX platforms that leverage technologies like Altera Arria SoC FPGAs and Texas Instruments KeyStone DSPs.

This combination of cutting-edge technology and standardisation is crucial for modern defence applications. Today’s high-performance signal processing systems must meet the mandate for modular, maintainable architectures. As defence systems evolve, this alliance between performance and openness will become increasingly critical for program success.