Entity

Source file	schemas/entity.schema.json
$id	https://synapsecommand.local/cdm/1.0.0/entity.schema.json
CDM schema version	1.0.0
SHA-256 of source	55d02434c12074c145da2364eb0be9a31a7d85625bcfa1dcb974b428af4d2299

Anything that exists on the map, at a stated time, with stated confidence.

Fields

Field	Type	Required	Description
affiliation	Affiliation	yes
attributes	object	no	Source-specific fields the CDM has no home for. The never-drop bag: park data here rather than discarding it.
confidence	number | null	no	0..1. None = unknown; 0 means certainty-that-not, which is a claim. Default null. (≥ 0; ≤ 1)
entity_id	string (uuid)	yes	Stable across updates — derived, see ids.derive(). Never drawn at random.
entity_type	EntityType	yes
integrity	Integrity | null	no	PQC signature block — designed, not yet populated. Default null.
kinematics	Kinematics | null	no	Default null.
object_kind	"entity"	no
position	Position | null	no	None = position unknown. NEVER a Position holding zeros. Default null.
schema_version	string	no	Semver of the CDM this object was written against. Default "1.0.0".
source	SourceRef	yes	Which adapter produced this object. Required on every kind.
source_ids	array<SourceId>	yes	Every external identifier this object is known by. At least one, on EVERY kind — see the class docstring. (min items 1)
symbol	string | null	no	MIL-STD-2525D SIDC, 20 digits. None when the source states no symbol — see symbology.sidc_from_affiliation() for deriving one. Default null.
valid_from	string	yes	When this state began. (pattern ^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}Z$)
valid_to	string | null	no	When it ceased. None = still current / open-ended. Default null. (pattern ^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}Z$)

:::info additionalProperties: false Unknown keys are rejected. That is safe only because the CDM pairs strictness with a declared escape hatch — Entity.attributes and Event.payload accept anything — so an adapter never has to choose between dropping a field and failing validation. :::

Referenced definitions

Every $ref on this page resolves to one of these, inlined here so the page is a complete reference and not a starting point for chasing pointers.

Affiliation

Maps to MIL-STD-2525 standard identity — see models.standard_identity().

Four members, not 2525's seven: PENDING, ASSUMED_FRIEND and SUSPECT are judgements a fusion layer makes, not facts an adapter can read off a wire format. An adapter that invented ASSUMED_FRIEND would be doing business logic, which adapters may not do. The source's own wording is preserved in attributes when it is finer than this.

Closed vocabulary — a value outside this list is invalid, and UNKNOWN is a

member rather than a null wherever the enum has one.

Value
FRIENDLY
HOSTILE
NEUTRAL
UNKNOWN

EntityType

Closed vocabulary — a value outside this list is invalid, and UNKNOWN is a

member rather than a null wherever the enum has one.

Value
UNIT
PLATFORM
SENSOR
FACILITY
EVACUEE_GROUP
INTERFERENCE_SOURCE
OVERLAY_OBJECT
UNKNOWN

Integrity

DESIGNED, NOT IMPLEMENTED — the field the PQC signature will occupy.

No crypto happens in this package (tests/test_cdm_boundary.py asserts the package imports no crypto module). The field exists from day one so that turning signing on is a value change rather than a schema change: a schema change would be a MAJOR bump rippling through every store and every consumer, and would arrive exactly when the signing work is already late.

algorithm is a free string rather than an enum, naming what the platform's ledger already uses — ML-DSA-87 for entry signatures, SLH-DSA for checkpoints. Free, because the algorithm that replaces those is not knowable now, and an enum would make the migration a MAJOR bump for a value nobody reasons over programmatically.

All three fields or none. A block holding a signature with no algorithm is unverifiable, and an unverifiable signature that LOOKS present is worse than an absent one: it reads as assurance to everything downstream that does not check.

Field	Type	Required	Description
algorithm	string	yes	e.g. ML-DSA-87, SLH-DSA-SHAKE-256s. (min length 1)
chain_hash	string	yes	Hash binding this object to the chain. (min length 1)
signature	string	yes	(min length 1)

additionalProperties: false — unknown keys are rejected. Source-specific fields belong in the declared extension bags (Entity.attributes, Event.payload).

Kinematics

Motion. Every field optional, and absent means UNKNOWN, never zero.

This is the AIS sentinel lesson in schema form: 0 kt is measured stillness, 0 deg is a course due north, 0 m/s climb is level flight. All three are real measurements, so none of them can double as "no data" — the adapter translates the source's sentinel to None.

Field	Type	Required	Description
climb_mps	number | null	no	Metres per second, negative = descending. Default null.
course_deg	number | null	no	Degrees true, [0, 360). Default null. (≥ 0; < 360)
speed_mps	number | null	no	Metres per second. Default null. (≥ 0)

additionalProperties: false — unknown keys are rejected. Source-specific fields belong in the declared extension bags (Entity.attributes, Event.payload).

Position

A fix. Both coordinates required — that is how the null-never-zero rule is structural.

An unknown position is the ABSENCE of this object (entity.position is None), never a Position holding zeros. Because lat and lon are required here, an adapter cannot express "unknown" as (0, 0) even by accident: it has to either omit the Position or state a real coordinate. Coordinate zero is a real point in the Gulf of Guinea, and a contact painted there is a contact that does not exist.

accuracy_m absent means unknown accuracy, NOT perfect accuracy. Zero would mean a fix with no error, which no sensor produces.

Field	Type	Required	Description
accuracy_m	number | null	no	Metres, 1-sigma. None = unknown, never 0. Default null. (≥ 0)
alt_m	number | null	no	Metres HAE. None = unknown. Default null.
lat	number	yes	WGS84 decimal degrees. (≥ -90; ≤ 90)
lon	number	yes	WGS84 decimal degrees. (≥ -180; ≤ 180)
position_source	PositionSource	yes	How the fix was obtained — the field that survives GNSS denial.

additionalProperties: false — unknown keys are rejected. Source-specific fields belong in the declared extension bags (Entity.attributes, Event.payload).

PositionSource

How the position was obtained. Load-bearing in a GNSS-denied environment.

This is the field that lets a commander tell a fix from a guess. When PNTMAP reports jamming over an area, every GNSS-sourced position inside that area becomes suspect and every INERTIAL or MANUAL one does not — a distinction that is impossible to make after the fact if the adapter flattened them all to "position".

Closed vocabulary — a value outside this list is invalid, and UNKNOWN is a

member rather than a null wherever the enum has one.

Value
GNSS
INERTIAL
MANUAL
ESTIMATED

SourceId

One external identifier for an object — the provenance mapping.

A list of these, not one, because the same object arrives from several systems: the same vessel is an MMSI to AIS, a track number to STANAG 4676 and a UID to TAK. Fusion joins them later; the adapter's job is to record which name its own system used, and never to overwrite another system's entry.

Field	Type	Required	Description
external_id	string	yes	That system's own identifier. (min length 1)
system	string	yes	The external system, e.g. PNTMAP, TAK. (min length 1)

additionalProperties: false — unknown keys are rejected. Source-specific fields belong in the declared extension bags (Entity.attributes, Event.payload).

SourceRef

Which adapter produced this object, from which system, and whether it is real.

synthetic is required and has no default. Every fixture in this repository is synthetic and every scenario package is too (TR-12), and the platform keeps the synthetic and live layers apart over one interface — so an object that does not say which layer it belongs to cannot be filed. A default of false would silently promote exercise data to operational data, which is the dangerous direction; a default of true would silently demote live data and hide it from an operator. There is no safe default, so there is no default.

Field	Type	Required	Description
adapter	string	yes	Adapter name, e.g. pntmap. (min length 1)
adapter_version	string	yes	Adapter semver. (min length 1)
synthetic	boolean	yes	true for anything not from a real source (TR-12).
system	string	yes	The external system this came from. (min length 1)

additionalProperties: false — unknown keys are rejected. Source-specific fields belong in the declared extension bags (Entity.attributes, Event.payload).