NMEA-GN-VTG

Description:

Standard NMEA: Course over ground and ground speed.

Configuration:

• NMEA-GN-VTG_GNSS for combined (average) output from both receivers

  • The course over ground and speed over ground are computed from the average position and velocity between GNSS1 and GNSS2. Note that this is not the same as the average of the individual COG and SOG.

  • The positioning mode is from the “best” receiver

• NMEA-GN-VTG_GNSS1 for output from GNSS 1 receiver

  • This is the standard NMEA VTG for GNSS1.

• NMEA-GN-VTG_GNSS2 for output from GNSS 2 receiver

  • This is the standard NMEA VTG for GNSS2.

• NMEA-GN-VTG_FUSION for output from Fusion

  • The course over ground and speed over ground are from fusion.

  • The positioning mode is:

    • When fusion is using GNSS: The GNSS state (RTK fixed, RTK float, SPP) of the best GNSS receiver.

    • When fusion not using GNSS: Dead-reckoning or no-fix depending on the state of fusion.

    • When fusion is not initialized: Not-valid, no matter the state of the GNSS receivers.

• NMEA-GP-VTG_GNSS, NMEA-GP-VTG_GNSS1, NMEA-GP-VTG_GNSS2 and NMEA-GP-VTG_FUSION

  • Legacy messages. These messages also have GN constellation but the talker ID is “GP”

Notes:

• These messages does not contain any information that would let one tell them apart. Do not enable more than one of these in the same port.

• This message is according to NMEA 0183 v4.11 (and erratas).

• It uses the “GP” talker ID even though the navigation solution is multi-GNSS.

Example message:

$GNVTG,0.0,T,,M,0.0,N,0.0,K,D*08\r\n

Example message with non-standard high-precision fields:

$GNVTG,0.0000,T,,M,0.01316,N,0.02437,K,D*3F\r\n

Message fields: