Functions
Ref. Model
I/O Data
SubAIMs
JSON MData
Profiles
Ref. Software
Conformance
Performance
1 Functions
The MAS Spatial Attitude Generation (CAV-MSA) AIM:
| Receives | Spatial Data | From the CAV’s motion sensors. |
| Produces | Spatial Attitude | To Ice Condition Analysis, MAS Response Analysis, and outside the MAS. |
The AIM gives the Spatial Attitude of the CAV by dead reckoning, from the motion sensors only: at each Spatial Data, the distance run since the last from the odometer; the heading turned over it from the gyroscope’s yaw rate; the position moved along the mean heading. Velocity comes from the speedometer, acceleration from the accelerometer, pitch and roll from the inclinometers. What the steered wheels report is not how the CAV moved, and is not used.
The frame is the MAS’s own: east and north metres from where the CAV was at the start, its initial heading given. What the MAS cannot know – an odometer that reads long, the bias of the gyroscope – is in the accuracy it states, which grows with the distance run. Spatial Attitude Generation in the ESS anchors it with GNSS.
2 Reference Model
Figure 1 depicts the Reference Model of the MAS Spatial Attitude Generation (CAV-MSA) AIM.
Figure 1 – The MAS Spatial Attitude Generation (CAV-MSA) AIM
3 I/O Data
Table 1 specifies the Input and Output Data of the MAS Spatial Attitude Generation (CAV-MSA) AIM.
| Input | Data Type | Description |
|---|---|---|
| Spatial Data | Spatial Data | Odometer, speedometer, accelerometer, inclinometers and gyroscope. |
| Output | Data Type | Description |
| Spatial Attitude | Spatial Attitude | The CAV’s Spatial Attitude by dead reckoning, on the MAS’s frame. |
4 SubAIMs
No SubAIMs.
5 JSON Metadata
https://schemas.mpai.community/CAV2/V2.0/AIMs/MASSpatialAttitudeGeneration.json
6 Profiles
No Profiles.
7 Reference Software
The reference software reckons the Spatial Attitude from the odometer, the gyroscope’s yaw rate, the speedometer, the accelerometer and the inclinometers, on the MAS’s own frame, its accuracy growing with the distance run. It is part of the reference software of CAV-TEC V2.0 (see N4195, An introduction to the reference software): C# on .NET 10, released under the BSD 3-Clause licence, obtained from MPAI.
Tested with the Motion Actuation Subsystem, Stage 1: the Spatial Attitude against the ground truth.
8 Conformance Testing
Table 2 provides the Conformance Testing Method for the MAS Spatial Attitude Generation (CAV-MSA) AIM: the data it receives and produces. If a schema references other schemas, conformance of data for the primary schema implies that data referencing a secondary schema shall also validate against that schema, if present, and conform with the Qualifier, if present.
| Receives | Spatial Data | Shall validate against the Spatial Data schema. |
| Produces | Spatial Attitude | Shall validate against the Spatial Attitude schema. |
