Putting the NGVA Data Model to work with OpenDDS

Anyone building sub-systems for the NATO Generic Vehicle Architecture (NGVA) may well note the lack of documentation on how to actually implement DDS and the NGVA Data Model. Most resources stop at theory. A white paper from Spectra Defense Technologies closes that gap with a real, working example built around the Spectra video recorder.

What NGVA sets out to solve

NGVA, defined in STANAG 4754, standardizes how sub-systems integrate on military land vehicles. The goal is simpler, more cost-effective and more agile integration, with lower risk and shorter deployment timelines. The standard covers architecture approach, power infrastructure, data infrastructure, crew terminal software architecture, data model, safety, and verification and validation. The white paper focuses on two pieces: the data exchange mechanism and the data model itself.

Why DDS is the backbone

NGVA relies on Data Distribution Service (DDS), a middleware built for data-centric sharing between machines and applications using a publish-subscribe pattern. DDS handles message addressing, marshalling, flow control and retries. Because NGVA requires implementations to follow the DDSI-RTPS interoperability protocol, sub-systems built on different DDS vendors can still talk to each other. That vendor flexibility is part of what makes the standard useful across a multi-supplier defense ecosystem.

For this project, Spectra engineers selected OpenDDS: an open-source, license-free implementation that supports DDSI-RTPS and places no obligation on users to redistribute source code.

Building from the ground up

The white paper walks through the full technical path, starting with building OpenDDS on CentOS Linux 7.8, then generating C++ code from two NGVA Data Model modules: Video and LDM Common. The Video module contains structures for controlling video devices; LDM Common holds structures shared across every module in the standard.

One detail worth noting for anyone attempting this themselves: the modules downloaded from the official NGVA site included IDL files for RTI Connext, not OpenDDS. Getting them to work with OpenDDS required adding “@topic” annotations before each data structure used as a topic, a small but necessary modification the paper documents structure by structure.

Three applications, one system

To prove the concept, Spectra built three applications that publish and subscribe across DDS topics:

• A video streaming application, which publishes stream information and responds to start and stop requests
• A video recording application, which publishes sink information and starts recordings when it receives a matching stream ID
• A controller application, which coordinates between the two by matching sink and stream IDs and issuing the requests that start recording and streaming

The white paper includes full system diagrams showing exactly how these applications communicate over DDS topics, down to the specific ID fields each message carries. For engineers evaluating how NGVA compliance might work in their own systems, this is the part worth studying closely.

The takeaway

The conclusion is straightforward: DDS itself is not complicated to use once it is running. The real variable is the NGVA Data Model implementation path. If a DDS supplier already provides usable IDL files, the work is minimal. If IDL files need to be generated from UML models using NGVA translators, the effort scales up depending on the chosen DDS implementation.

For teams evaluating NGVA integration or looking for one of the only detailed, hands-on references on this exact combination of standards, the full white paper covers build commands, IDL processing steps, and complete topic-level system diagrams that go well beyond what fits here.

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FAQ

What is NGVA?

NGVA, or NATO Generic Vehicle Architecture, is an open standard defined in STANAG 4754. It standardizes how sub-systems integrate on military land vehicles, covering areas such as architecture approach, power infrastructure, data infrastructure, crew terminal software architecture, the data model, safety and verification and validation.

What DDS implementation does the white paper use, and why?

The white paper uses OpenDDS, an open-source DDS implementation that is free of licensing fees, supports the DDSI-RTPS interoperability protocol NGVA requires, and does not obligate users to redistribute their source code.

Which parts of the NGVA Data Model does the example cover?

It covers the Video module, which contains data structures for controlling video devices, and the LDM Common module, which contains data structures shared across all NGVA modules.

What did Spectra actually build to prove the concept?

Three applications: a video streaming application, a video recording application and a controller application. Together they publish and subscribe to DDS topics to start and stop video streaming and recording on the Spectra video recorder.

What makes NGVA implementation complex, if DDS itself is simple?

Complexity depends on whether usable IDL files already exist for the chosen DDS supplier. If they do, implementation is straightforward. If IDL files must be generated from the NGVA UML models using NGVA translators, the effort increases depending on the DDS implementation chosen.