Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment
1 Definition
A Data Type representing an Object’s position, velocity, and acceleration.
2 Functional Requirements
- The Position of an Object is given by the Coordinates of a representative point of the Object.
- Cartesian and Polar Coordinate Systems are supported.
- An Object may have one of the following attributes: Speech, Audio, Visual, 3D Model, Audio-Visual, Haptic, Smell, RADAR, LiDAR, Ultrasound.
- Accuracy is the estimated absolute difference between the measured spatial values of each of CartPosition, SpherPosition, CartVelocity, SpherVelocity, CartAccel, SpherAccel and their true value.
3 Syntax
https://schemas.mpai.community/OSD/V1.5/data/Position.json
4 Semantics
Table 1 provides the semantics of Position. Each of Position, Velocity, and Acceleration can be expressed either in Cartesian (X,Y,Z) or Spherical (r,φ,θ) Coordinates.
| Header | Position Header – Standard “OSD‑OPS‑Vx.y”. |
| MInstanceID | Identifier of the M-Instance (Virtual Space) where this Position is defined. |
| UEnvironmentID | Identifier of the U-Environment (Real Space) where this Position is defined. |
| PositionID | Unique identifier of this Position instance. |
| PositionTime | Time this Position instance was produced. |
| PositionSpaceTime | Space/Time where/when this Position applies. |
| General | General classification data of the Object. |
| – CoordType | Coordinate type: one of Cartesian, Spherical, Geodesic, Toroidal. |
| – ObjectType | Type of the Object: one of Digital Human, Generic. |
| – MediaType | Media type: one of Speech, Audio, Visual, 3D Model, Audio-Visual, Haptic, Smell, RADAR, LiDAR, Ultrasound. |
| Position | |
| – CartPosition (X,Y,Z) | Cartesian position (X, Y, Z) in metres. |
| – CartPositionAccuracy (X,Y,Z) | Accuracy of each Cartesian position component (X, Y, Z) in metres. |
| – SpherPosition (r,φ,θ) | Spherical position (r, φ, θ) in metres and degrees. |
| – SpherPositionAccuracy (r,φ,θ) | Accuracy of each spherical position component (r, φ, θ). |
| Velocity of Position | |
| – CartVelocity (X,Y,Z) | Cartesian velocity (X, Y, Z) in metres/s. |
| – CartVelocityAccuracy (X,Y,Z) | Accuracy of each Cartesian velocity component (X, Y, Z) in metres/s. |
| – SpherVelocity (r,φ,θ) | Spherical velocity (r, φ, θ) in metres/s and degrees/s. |
| – SpherVelocityAccuracy (r,φ,θ) | Accuracy of each spherical velocity component (r, φ, θ). |
| Acceleration of Position | |
| – CartAccel (X,Y,Z) | Cartesian acceleration (X, Y, Z) in metres/s². |
| – CartAccelAccuracy (X,Y,Z) | Accuracy of each Cartesian acceleration component (X, Y, Z) in metres/s². |
| – SpherAccel (r,φ,θ) | Spherical acceleration (r, φ, θ) in metres/s² and degrees/s². |
| – SpherAccelAccuracy (r,φ,θ) | Accuracy of each spherical acceleration component (r, φ, θ). |
| DataXMData | MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this Position in a trusted data exchange context. |
| DescrMetadata | Human-readable descriptive metadata of the Position instance (plain text, max 2048 characters). |
5 Conformance Testing
A Data instance conforms with Position (OSD‑OPS) if:
- The Data validates against the Position’s JSON Schema.
- All Data in the Position’s JSON Schema:
- Have the specified type.
- Validate against their JSON Schemas.
- Conform with their Data Qualifiers.
6 Performance Assessment
Not part of this specification.
