Appendix G: Frame Identifiers (Normative)

SpatialDDS represents reference frames using the FrameRef structure:

struct FrameRef {
  uuid uuid;           // globally unique frame ID
  string fqn;          // optional fully-qualified name, e.g. "earth-fixed/map/cam_front"
};

UUID Rules

  • uuid is authoritative for identity.
  • fqn is an optional human-readable alias.
  • Implementations MUST treat uuid uniqueness as the identity key.
  • Deployments SHOULD establish well-known UUIDs for standard roots (e.g., earth-fixed, map, body) and document them for participants.

Name and Hierarchy Rules

  • fqn components are slash-delimited.
  • Reserved roots include earth-fixed, map, body, anchor, local.
  • A FrameRef DAG MUST be acyclic.

Manifest References

Manifest entries that refer to frames MUST use a FrameRef object rather than raw strings. Each manifest MAY define local frame aliases resolvable by fqn.

Notes

This appendix defines the authoritative encoding for FrameRef. Additional derived schemas (e.g. GeoPose, Anchors) SHALL refer to this definition by reference and MUST NOT re-declare frame semantics.