Open Architecture Field Guide

Part of the Open Architecture Field Guide. All information is derived from unclassified, publicly releasable (Distribution A) sources.

The Department of Defense has several open architectures, not one: separate standards for hardware, software, mission systems, and navigation, each owned by a different office and connected only where a program chooses. This guide maps the four families and shows how they fit.

Four families of standards sit under two non-technical drivers. Almost everything else in this guide is a piece of one of them.

Spectral Autonomy

It is not one stack

Two things sit above everything else, and neither is a technical standard. MOSA, the Modular Open Systems Approach, is an acquisition requirement written into U.S. law. It requires modular designs and open interfaces, but it does not tell a program which architecture or standard to use. JADC2, Joint All-Domain Command and Control, is an operational goal, connecting sensors and shooters across every domain. It sets the objective, not the design.

Below them, four families of standards do the actual work. They were developed separately, and they reference each other inconsistently rather than nesting into a single hierarchy.

The four families

Hardware covers the cards, chassis, backplanes, and RF paths of defense electronics. OpenVPX is the physical foundation. SOSA adds sensor and electronic-warfare requirements on top. CMOSS, HOST, MORA, and VICTORY cover service-specific and RF-specific pieces.

Software and interfaces covers how mission software is built and how systems talk to each other. FACE governs software portability across aircraft. OMS provides a mission-system abstraction layer, UCI defines the messages that move across it, and DDS is a common transport.

Government Reference Architectures are an Air Force family that defines how a whole mission system is organized: AMS-GRA for mission systems, A-GRA for autonomy, GARA for avionics integration, and W-GRA for weapons. They are separate architectures owned by different offices, not one nested set. Big Iron, the Air Force electronic-warfare architecture, was absorbed into AMS-GRA at version 14.0.

Positioning, navigation, and timing covers how a platform knows where and when it is when GPS is contested. The Army's pntOS and the shared ASPN data standard are one line of effort, and the Air Force's R-EGI is another. As of 2026, pntOS and ASPN are governed by a shared industry-government consortium.

Spectral Autonomy

A note on governance

Two kinds of standard live in these families, and the difference matters when a program bets on one. Some standards (OpenVPX, SOSA, FACE, DDS) are developed by multi-stakeholder consortia, with published specifications and formal ballot processes. Others (the Government Reference Architectures, OMS and UCI, CMOSS, MORA, VICTORY) are owned by a single service office and can change at that office's direction. Both are open, in different senses.

Spectral Autonomy

Reading this guide

Each standard and reference architecture has its own explainer.

Policy

• What MOSA Actually Requires, the statutory mandate the rest satisfy.

Government Reference Architectures

• AMS-GRA, the modular mission-systems architecture.
• A-GRA, the autonomy architecture.
• GARA, the avionics-integration architecture.
• Big Iron, the electronic-warfare architecture, now part of AMS-GRA.

Software and interfaces

• OMS, the mission abstraction layer.
• UCI, the common message set.
• FACE, the software-portability standard.
• DDS, the publish-subscribe transport.

Hardware

• OpenVPX, the physical foundation.
• SOSA, the sensor and electronic-warfare hardware standard.
• CMOSS, the Army modular suite.
• MORA, the RF-chain standard.

Positioning, navigation, and timing

• pntOS, the PNT fusion framework.
• ASPN, the shared data standard.
• R-EGI, the Air Force resilient GPS/INS.
• The PNT Standards Consortium, the new governance body.