Go to CAV-TEC V2.0 Data Types

Definition
Functional Requirements
Syntax
Semantics
Conformance
Performance

1 Definition

A Message sent by:

  • The AMS to the MAS requesting it to move the CAV along the specified Trajectory.
  • The MAS to the AMS informing it about the execution of the last AMS‑MAS Message.

2 Functional Requirements

The AMS‑MAS Message sent by the AMS to the MAS contains:

  • Trajectory – the path to be executed.
  • Command – one of the following Actions:
  • Execute: execute the Trajectory, changing the CAV’s Spatial Attitude SAA at time tA to Spatial Attitude SAB at time tB.
  • Suspend: temporarily stop executing the current Trajectory.
  • Resume: continue execution of the suspended Trajectory.
  • Change: replace the current Trajectory with a new one.

When receiving an AMS‑MAS Message, the MAS implements the requested Action and may issue a series of AMS‑MAS Messages at intermediate Positions containing:

  • CurrentTime – the current Time.
  • CAV Spatial Attitude – estimated from MAS‑internal sensors.
  • Road State – reported when significant divergence between expected and actual Spatial Attitude is detected (e.g., Ice Conditions, Submersion).
  • CAV State – current functional state of the CAV.

These updates inform the AMS about the progress of executing the AMS‑MAS Message.

In CAV-TEC V2.0 the AMS sends, with each Trajectory, the CAV’s Spatial Attitude as it knows it – GNSS and the MAS’s own estimate combined by the Environment Sensing Subsystem – and the MAS follows the Trajectory from it: the MAS executes, and where the CAV is, is known best upstream. The MAS answers each AMS-MAS Message with its own Spatial Attitude and the Road State, so that the AMS knows what the CAV can do.

3 Syntax

https://schemas.mpai.community/CAV2/V2.0/data/AMSMASMessage.json

4 Semantics

Table 1 specifies the semantics of the AMS-MAS Message Data Type.

Table 1 – Semantics of the AMS-MAS Message Data Type

Label Type Req. Description
Header string (CAV-AMM-V2.0) Yes AMS-MAS Message Header – Standard CAV-AMM-Vx.y
MInstanceID string Identifier of the M-Instance (Virtual Space) associated with this AMS-MAS Message.
UEnvironmentID string Identifier of the U-Environment (Real Space) associated with this AMS-MAS Message.
AMSMASMessageID string Yes Unique identifier of this AMS-MAS Message instance.
AMSMASMessageTime Simple Time Time this AMS-MAS Message was produced.
AMSMASMessageSpaceTime Simple Time Time this AMS-MAS Message was sent.
AMSMessage object Data in message from AMS to MAS.
AMSMessage.Trajectory Trajectory Trajectory to be executed by the MAS.
AMSMessage.SpatialAttitude Spatial Attitude The CAV’s Spatial Attitude as the AMS knows it – GNSS and the MAS’s own estimate combined – on the frame of the Trajectory: what the MAS follows the Trajectory from.
AMSMessage.Command string Command to apply to the current Trajectory. One of: Execute, Suspend, Resume, Change.
MASMessage object Data in message from MAS to AMS.
MASMessage.CurrentTime Simple Time Current Time at which this MAS Message was produced.
MASMessage.SpatialAttitude Spatial Attitude CAV Spatial Attitude estimated from MAS-internal sensors.
MASMessage.RoadState Road State Road State reported when significant divergence between expected and actual Spatial Attitude is detected.
MASMessage.CAVState CAV State Current functional state of the CAV.
DataXMData Data Exchange Metadata MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this AMS-MAS Message in a trusted data exchange context.
DescrMetadata string Human-readable descriptive metadata of the AMS-MAS Message (plain text, max 2048 characters).

5 Conformance Testing

Data conform to the AMS-MAS Message Data Type when they validate against its schema. If the schema references other schemas, data referencing a secondary schema shall also validate against that schema, if present, and conform with the Qualifier, if present.

6 Performance Assessment