1 Definition
Global Navigation Satellite System (GNSS) Data for a constellation of satellites that transmit positioning and timing data to GNSS receivers to determine their location.
2 Functional Requirements
GNSS Data can come from four GNSSs – GPS (US), GLONASS (RU), Galileo (EU), BeiDou (CN) and two regional systems – QZSS (Japan) and IRNSS or NavIC (India). Position accuracy depends on the GNSS system.
3 Syntax
https://schemas.mpai.community/CAV2/V1.0/data/InputGNSS.json
4 Semantics
Label | Size | Description |
Header | N1 Bytes | GNSS Data Header |
– Standard | 9 Bytes | The characters “CAV-IGN-V” |
– Version | N2 Bytes | Major version – 1 or 2 Bytes |
– Dot-separator | 1 Byte | The character “.” |
– Subversion | N3 Bytes | Minor version – 1 or 2 Bytes. |
InputGNSSID | N4 Bytes | Identifier of Input GNSS Data. |
GNSSSensorID | N4 Bytes | Identifier of GNSS Sensor. |
InputGNSSTimeSpace | N5 Bytes | Total duration of Input GNSS Data. |
– Duration | N6 Bytes | Duration of GNSS Data Block. |
– SpatialAttitude | N7 Bytes | CAV’s Spatial Attitude when getting Data. |
InputGNSSData | N8 Bytes | Set of Input GNSS Data |
– InputGNSSFormatID | N9 Bytes | Format ID of Input GNSS Data. |
– InputGNSSDataLength | N10 Bytes | Data Length of Input GNSS Data in Bytes. |
– InputGNSSDataURI | N11 Bytes | Location of Input GNSS Data. |
InputGNSSAttributes[] | N12 Bytes | Set of Input GNSS Data Attributes |
– InputGNSSAttributeID | N13 Bytes | ID of Attribute of Input GNSS Data |
– GNSSAttributeFormatID | N14 Bytes | ID of Attribute Format of Input Audio Data |
– InputGNSSAttributeLength | N15 Bytes | Number of Bytes in Input GNSS Data |
– InputGNSSAttributeDataURI | N16 Bytes | URI of Data of Input GNSS Data |
5 Data Formats
Some data formats are:
- GPS Exchange Format (GPX): an XML schema providing a common GPS data format that can be used to describe waypoints, tracks, and routes.
- Environment Geodetic System (WGS): definition of the coordinate system’s fundamental and derived constants, the ellipsoidal (normal) Earth Gravitational Model (EGM), a description of the associated Environment Magnetic Model (WMM), and a current list of local datum transformations.
- International GNSS Service (IGS) SSR: format used to disseminate real-time products to support the IGS (igs.org) Real-Time Service. The messages support multi-GNSS and include corrections for orbits, clocks, DCBs, phase-biases and ionospheric delays. Extensions are planned to also cover satellite attitude, phase centre offsets and variations and group delay variations.
6 To Respondents
Respondents are requested to:
- Comment on the functional requirements.
- Propose Data Formats and Attributes for use in the future Technical Specification: Data Types, Formats, and Attributes (MPAI-TFA).