STANAG 4603 modelling and simulation architecture (HLA)

What it is

STANAG 4603 is not itself a technical specification. It is the agreement by which NATO nations commit to a technical specification that lives elsewhere: the IEEE 1516 series, better known as the High Level Architecture (HLA), the framework that lets modelling and simulation (M&S) systems built by different organisations, in different countries, interoperate. Edition 3 was promulgated on 16 March 2023 and supersedes Edition 2 of 17 February 2015; the document states the only substantive change is adding SISO-STD-012 to its list of other related documents and moving to the current STANAG template, so the underlying commitment to IEEE 1516, 1516.1 and 1516.2 carries over unchanged.

The agreement exists to answer one interoperability requirement: connecting Level 3 (command and staff), Level 2 (tactical) and Level 1 (individual and crew) M&S systems that are used for operations, training and analysis, where those systems are developed by, and located in, different NATO nations.

Who it binds, and how

STANAG 4603 is addressed to participating nations and NATO bodies, not to a supplier or manufacturer directly. It binds a nation once ratified, as recorded in the NATO Standardization Document Database (NSDD); nations are invited to advise the NATO Standardization Office of their ratification and implementation intentions, and to report implementation details through NATO's electronic reporting tool afterwards. The document's own NATO Effective Date field reads "Not applicable", so there is no calendar date at which this reaches a company. A supplier meets STANAG 4603 the same way it meets any NATO architecture agreement: indirectly, when a national programme or a contract specifies HLA (IEEE 1516) compliance. That contract clause, not the STANAG itself, is where the obligation actually lands on a company building or maintaining a simulation federate.

What nations actually agree to

The STANAG's own standards section names exactly three documents participating nations agree to implement: IEEE 1516 (the HLA framework and rules), IEEE 1516.1 (the federate interface specification) and IEEE 1516.2 (the object model template specification). Those three IEEE documents, not the two pages of the STANAG, carry the actual technical interoperability requirements.

Clause 1 of the implementation section covers new development: when procuring or developing new M&S systems, a nation ensures those systems are compliant with the latest IEEE series of standards cited, based on its own national requirements. The STANAG does not itself specify how compliance is demonstrated; it leaves that to the nation.

Existing systems are not stranded by a new edition. Clause 2 lets federations built to an earlier HLA edition continue operating without being brought into conformance with the current version, so a working system is not obliged to chase every revision. The only point where nations have to actively reconcile editions is clause 3's case: an older system that has to interoperate fully with, or be conformant with, a federation on a later edition. There, the STANAG puts the decision in the hands of the two simulation managers involved, who determine the least costly or best technical approach between them. It does not prescribe which approach to take.

Clause 4 has participating nations agree to use the HLA Compliance Certification Process established by the NATO Modelling and Simulation Group (NMSG), though the STANAG names the process without describing how it works. Clause 5 is a separate, more concrete obligation: submitting details of national M&S federates and federations proposed for NATO use, and submitting equivalent details to withdraw one, both in the format set out in SRD 4603.1. Clause 6 keeps the references current: whatever edition of a cited document is currently in effect is the applicable one for developing simulation federations, and a revision to one of those documents does not require the STANAG itself to be resubmitted for ratification. An administrative note reinforces the same point for the IEEE references specifically: they should always be checked for newer versions before being applied.

How you are evaluated

Two different mechanisms sit side by side in this STANAG, and they are easy to conflate. The HLA Compliance Certification Process (clause 4) is a NATO-administered process for certifying federates and federations for NATO use; the document gives no detail on how it is run, who conducts it, or what evidence it examines, so nothing more than its name should be assumed. Separate from that, clause 5's reporting obligation is not an audit at all: nations submit details of the federates and federations they propose for NATO use, and NATO records the ratification and implementation status nations report through the NSDD and the electronic reporting tool. Neither mechanism is a certification of a company or its management system, and neither is something a vendor can hold on a customer's behalf.

Standards it references

• IEEE 1516 - the HLA framework and rules document, the specification participating nations commit to implementing. The STANAG's agreement binds on this document; it does not restate it.
• IEEE 1516.1 - the federate interface specification, one of the three documents nations agree to implement.
• IEEE 1516.2 - the object model template (OMT) specification, the third of the three.
• AAP-03 - the STANAG states its own review is conducted in accordance with AAP-03, with the result recorded in the NSDD. This governs how the STANAG's own currency is maintained, not a technical requirement on a supplier.
• IEEE 1516.4, IEEE 1730 and SISO-STD-012 are named under the STANAG's Other Related Documents heading - verification, validation and accreditation guidance; the distributed simulation engineering and execution process (DSEEP); and the federation engineering agreements template (FEAT), respectively. We do not hold catalogue pages for these three; the STANAG lists them as related reading, not as something nations agree to implement.

All three IEEE documents are published and sold by IEEE, not by NATO or by us. Copies are available from the IEEE Digital Library at www.ieee.org.

Standards it references

• AAP-03Background