ANEP-82 message specification for the CMS to IDATS data link

What it is

ANEP-82, "Message Specification for Data Link between Combat Management Systems and IDATS," is a NATO Allied Naval Engineering Publication. It defines the message protocol used to send ship sensor data from a Combat Management System (CMS) to the NATO FORACS programme's Integrated Data Acquisition Test System (IDATS), which the FORACS Project uses "to collect and process sensor data during sensor accuracy tests." It is a wire-format specification for a single test interface, not a management system, a quality-assurance standard or a physical handling procedure.

The document is addressed to "the developer and the integrator of a national interface between the nation's CMS and NATO FORACS IDATS," and it names who carries that job in practice: the filtering system's implementation "is the CMS vendor's responsibility in accordance with the nation's interests and requirements." It reaches that developer through STANAG 4710, the agreement nations ratify to use it; ANEP-82 itself is the technical content that agreement covers, not something a supplier is bound by on its own account.

Two message types and a small syntax

There are only two message types: a Sensor Data Message, carrying "one observation from one data source," and a Time Synchronization Message, carrying the CMS clock's current time so IDATS can check it has not drifted. Every message is ASCII text built from comma-separated data-item segments, each a colon-separated run of a descriptor token, an optional unit qualifier, and an optional extra descriptor. Two rules cut across the whole syntax: duplicate descriptors are not allowed within one message, and a sensor data message always carries a time-of-validity segment: one that lacks it "cannot be processed" at all.

Transport, timing and the checksum

The interface runs over serial RS-232 (9600 baud minimum, each message opening with $SIIS, and ending on a line feed) or Ethernet, where each UDP packet carries exactly one message to a default port of 4100. Timing is tight in one place: a time-synchronization message has to reach IDATS-IC with a total acquisition-and-transmission latency "not exceeding 20 ms," because IDATS treats the value as the CMS's actual clock reading. A checksum is optional and recommended only for serial links, computed as an 8-bit exclusive-OR across the message.

The token vocabulary, and its legacy corner

Most of the document's length is two reference tables: the data-item descriptors (bearing, range, position on each axis, depression/elevation angle, height, latitude and longitude with a choice of geodetic datum, heading, pitch, roll, sound velocity and more) and the units they carry. Reading only the worked examples in Annex A risks missing something Annex B states plainly: pitch and roll still appear in the table but the document says each "remains in the list of descriptors for backward compatibility," while the current tokens, pire and rore, "must be used instead." A CMS can also send data outside the approved list through a user-defined descriptor, which IDATS records but does not otherwise process.

How conformance actually works

ANEP-82 sets out no certification, accreditation or audit scheme, and no external body assesses an implementation against it. Conformance is functional: an interface either produces messages IDATS-IC can parse correctly, or it does not. The document's own examples of this are blunt. A message missing its time-of-validity segment cannot be processed at all, and a descriptor the CMS invents outside the approved list is simply parsed and filed away, with no further processing applied to it. The only real proof an implementation works is that IDATS receives, timestamps and processes what a ship's interface sends it during an actual FORACS test.

What it does not cover

ANEP-82 is explicit that "the interface between CMS and IDATS is not covered by any other NATO publication," so there is no separate standard governing this specific link. It also leans on STANAG 4222, "Method of expressing navigation accuracy," for the axis convention behind several position tokens, and it does not attempt to define that convention itself. Annex A's worked message examples are stated to be indicative, not exhaustive: they do not "cover all the different messages that can be output by a CMS."

ANEP-82 is published by the NATO Standardization Office and listed in the NATO Standardization Document Database free of charge. NATO's documents are not sold by ComplyTrain and we host no copies of them.

Standards it references

• ANEP-31Background