In today’s technology-rich battlefield, new threats emerge and change quickly. Rapidly responding to new threats in this dynamic environment is one of the primary drivers behind the DoD mandate to adopt a Modular Open Systems Approach (MOSA) for procurement across the Army, Air Force, and Navy. The MOSA mandate drives a modular approach to system design that lowers the cost of integration and speeds the deployment of new capabilities to address emerging threats.

The MOSA directive has greatly accelerated the adoption of open system standards, such as the U.S. Army CCDC C5ISR Center’s Army’s Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) Modular Open Suite of Standards (CMOSS) and the Sensor Open Systems Architecture (SOSA) Technical Standard, supported by the Tri-Services and led by The Open Group’s SOSA Consortium. Defense system integrators need to understand the MOSA mandate and become familiar with leading MOSA-aligned standards, such as CMOSS and SOSA, before developing system solutions.

The Importance of MOSA

While the MOSA philosophy delivers many benefits to DoD procurement efforts, such as lowered costs, greater interoperability, and faster deployment, it can be a challenge for system designers to understand the interrelationship between the recent mandate and the leading open standards that are aligned to support it. The following overview is intended to provide a basic introduction to the MOSA philosophy and some of the most important MOSA-aligned standards, such as CMOSS, SOSA, FACE, HOST, MORA, OpenVPX, and VICTORY.

The Modular Open Systems Approach

“[An open system architecture]uses a technical architecture that adopts consensus-based standards supporting a modular, loosely coupled, and highly cohesive system structure that includes the publishing of key interfaces within the system and relevant design disclosure.” (DAU Glossary)

Figure 1. MOSA Principles/Benefits

MOSA, which is now the DoD’s preferred method for implementation of open systems, is also required by United States law. Title 10 U.S.C. 2446a.(b), Sec 805 states that all major defense acquisition programs (MDAP) are to be designed and developed using a MOSA.

Major defense programs must employ a modular design that uses major system interfaces between a major system platform and a major system component, between major system components, or between major system platforms. The modular design must be subjected to verification to ensure major system interfaces comply with, if available and suitable, widely supported and consensus-based standards. Adherence with MOSA directives results in a system architecture that allows severable major system components at the appropriate level to be incrementally added, removed, or replaced throughout the life cycle of a major system platform to afford opportunities for enhanced competition and innovation.

DoD is now actively pursuing MOSA in the life cycle activities of its Major Defense Acquisition Programs and Major Automated Information Systems, to keep pace with the rapid evolution in technology and threats that require faster cycle time for fielding and modifying warfighting capabilities.

Figure 2. THe SOSA approach to leveraging existing open standards.

A key enabler for MOSA is the adoption of an open business model, which requires doing business in a transparent manner and leveraging the collaborative innovation of numerous participants across the DoD enterprise, to share risk, maximize reuse of assets, and reduce ownership cost. MOSA allows the DoD to incrementally acquire warfighting capabilities, including systems, subsystems, software components, and services, with more flexibility, competition, and innovation. The key goals of MOSA include:

  • Significant cost savings or avoidance;

  • Schedule reduction and rapidly deploy new technology;

  • Opportunities for technical upgrades and refresh;

  • Increased interoperability, including system of systems interoperability and mission integration;

  • Additional benefits during the sustainment phase of a major system.

MOSA Enabling Standards

It’s important to keep in mind that MOSA is not itself a standard, but rather a procurement philosophy for which a number of existing aligned standards serve as instantiations. These MOSA enabling standards are widely accepted, supported and consensus-based, and set by recognized standards organizations or the marketplace.

Examples of MOSA Enabling Standards:

Figure 3. Curtiss-Wright’s MOSA-based CMOSS/SOSA Starter Kit (CSSK), designed for use on ground combat vehicle (GCV) platforms, speeds the development and demonstration of CMOSS/SOSA solutions with a pre-integrated 4-slot SOSA-aligned 3U VPX system that combines an A-PNT module, VICTORY network module, single board computer and power supply unit.

CMOSS: CMOSS is a suite of standards developed and maintained by the US Army to support Army procurements that respond to program office schedules and needs. CMOSS solutions facilitate a Universal A-Kit that enables project managers to field capabilities as cards into a common chassis, while eliminating the need for platform specific integration. Using CMOSS, capabilities can be fielded as cards in common chassis and antennas/amplifiers using existing cabling. CMOSS is divided into a software layer, functional decomposition layer, hardware layer and network layer, with MOSA aligned standards identified to realize each layer.

CMOSS standards support the reduction of the size, weight and power of C5ISR and EW systems while increasing the flexibility and adaptability of these systems. For example, CMOSS reduces the SWaP footprint of C4ISR systems through shared resources for external sensors, antennas, and amplifiers. It enables rapid technology insertion using best of breed capabilities to address emerging requirements and lays the foundation for enhanced interoperability and simultaneity amongst C4ISR capabilities.

The CMOSS Software Layer

Figure 4. The SOSA-aligned VPX3-670 A-PNT card integrates a CSAC, IMU, and GBGRAM Type-II SAASM/M-Code receiver. External network-enabled sensors can also be added and integrated with the pntOS software.

CMOSS has adopted frameworks that abstract the hardware from the software to enable software portability and reuse. These frameworks include:

  • FACE: The Open Group’s Future Airborne Capability Environment (FACE) Consortium defines standards for avionics and general purpose computing

  • REDHAWK: The National Security Agency’s (NSA) REDHAWK is a software-defined radio (SDR) framework designed to support the development, deployment, and management of real-time software radio applications. It provides tools that allow development and testing of software modules called “Components” and composition of Components into “Waveform Applications” that can be seamlessly deployed on a single computer or multiple network-enabled computers. REDHAWK is released to Open Source Software (OSS) and is available to the public.

The CMOSS Functional Decomposition Layer

  • MORA: The Army’s Modular Open RF Architecture (MORA) core objective is to logically decompose radio frequency (RF) systems for efficiency, flexibility, reusability, and scalability while enabling management, health monitoring, and sharing of raw and/or processed data. It provides a decomposition for radios, establishes the radiohead construct, remoting the amplifier with the antenna so that antennas, amplifiers and RF resources on the platform can be shared. MORA is an extension of the Army’s Vehicular Integration for C4ISR/EW Interoperability (VICTORY) architecture.

The CMOSS Hardware Layer

  • OpenVPX: The CMOSS hardware layer adopts the Open-VPX standard, defined by the VITA trade association’s VITA Standards Organization (VSO). Based on VITA’s VPX standards, which define 3U and 6U modules, it is focused on system-level requirements to improve interoperability and reduce customization, testing, cost, and risk. OpenVPX was created to answer this system-level need. OpenVPX defines a set of system implementations within VPX, including multiple planes for Utility, Management, Control, Data and Expansion

The CMOSS Network Layer:

  • VICTORY: The Army’s Vehicular Integration for C4ISR/EW Interoperability (VICTORY) standard establishes the network data bus on the platform and allows the discovering and sharing of services such as PNT. It enables pooled radio resources such as antennas and amplifiers for Communications, EW and SIGINT systems. VICTORY enables shared processing resources such as computers and displays, and shared data services such as PNT. It provides a foundation for enhanced interoperability and simultaneity between C5ISR systems and enables the rapid insertion of new technology and capabilities.

HOST: The US Navy’s HOST Standard provides the hardware framework for developing open embedded systems for U.S. military defense systems, including communications systems, mission computing systems, Positioning Navigation and Timing (PNT) systems, and Electronic Warfare (EW) systems. HOST started as an OpenVPX standard for computing-oriented rugged electronics, while CMOSS began as an OpenVPX standard for RF oriented electronics. HOST uses commercial-off-the-shelf (COTS) technology to develop a non-proprietary and publicly available architecture standard, allowing unlimited access to all necessary information to produce aligned hardware and modules.

OMS: The US Air Force’s Open Mission Systems (OMS) is a government-owned non-proprietary mission system architectural standard that enables affordable technical refresh and insertion, simplified mission systems integration, service reuse and interoperability, and competition across the lifecycle. It focuses on the interfaces between software services and hardware subsystems, and how data is exchanged across those interfaces. It allows the rapid integration of new sensor capabilities, subsystems/payloads and services.

SOSA: Supported by the tri-services, the Army, Air Force, and Navy collaborate under the SOSA Consortium to develop a holistic open architecture that leverages existing standards, maximizes economies of scale, and provides the flexibility to rapidly insert the latest capabilities to achieve Future Force Modernization. SOSA fosters interoperability of sensor processing hardware and software to eliminate vendor lock and proprietary architectures, thereby lowering the cost and speed the deployment of new capabilities and ideas from more technology providers to address threats. The SOSA Consortium builds on existing open standards, both government-based and industry-based, including CMOSS, OpenVPX, HOST, MORA and VICTORY.

The over 100 members of the Open Group SOSA Consortium bring together DoD, industry, and academia under a rigorous consensus-based approach for standards development. The Army strives to maintain alignment between CMOSS and the SOSA Technical Standard, and accordingly, SOSA leverages CMOSS development, and US Army CMOSS developers serve in many key roles within the consortium.

Highlighting the importance of these MOSA-aligned standards, the Secretary of the Army was asked to provide a briefing to the House Committee on Armed Services, by December 30, 2021, on plans for the establishment of a governance system for CMOSS that includes the formal assignment of responsibility, authority, and accountability for the development of CMOSS standards and their enforcement. The Committee directed that the briefing should include how such a governance system incentivizes programs of record to ensure their compliance with current and future CMOSS requirements.

This article was written by Jason DeChiaro, Technical Product Manager and Jacob Sealander, Director of Engineering and Advanced Systems, Curtiss-Wright Defense Solutions (Ashburn, VA). For more information, visit here .