2.3 | GNSS Receiver & IMU Compatibility

The requirements below outline the important components and considerations for using a GNSS receiver with COMMAND.
StarFire RTK, NMEA 0183 Fixed RTK over RS232 serial, or NMEA 2000 Fixed RTK output over ISOBUS/CANBUS.
Suitable adapters are available to connect RS232 or CANBUS and 12V external power to the COMMAND harnessing system. 
Ruggedised and suitable for earthmoving machine control applications.
Receivers being used with COMMAND must be capable of RTK positioning calculations. 
NMEA 2000 (CANBUS)
COMMAND is able to interface with GNSS receivers supporting NMEA 2000 standard output over ISOBUS/CANBUS for position feedback including but not limited to Case Vector Pro, New Holland PLM Cygnus & Trimble NAV 900/960 receivers.
Supported NMEA 2000 PGNs
129029 - GNSS Position Data
129539 - GNSS DOPs
129025 - Position, Rapid Update
129026 - COG & SOG, Rapid Update
129028 - Altitude Delta, Rapid Update
Position Update Rate 
A minimum position update rate of 5 Hz is required. 10 Hz is recommended.
NMEA 0183 (RS232 Serial)
COMMAND is able to interface with any receiver capable of providing NMEA 0183 standard sentences over RS232 serial for position feedback. The sentences below are required at a minimum for usage with COMMAND. 
Required Sentences
GGA -  Time, position, and fix related data
GSA -  GNSS DOP and active satellites
VTG - Actual track made good and speed over ground
Optional Sentences
RMC - Position, Velocity, and Time
ZDA - UTC day, month, and year, and local time zone offset
Position Update Rate 
A minimum message rate of 5 Hz is required. 10 Hz is recommended. 
RS232 Baud Rate
The RS232 baud rate can be selected in COMMAND as 19200, 38400, 57600, and 115200 bps. A baud rate of 38400 is recommended.
John Deere StarFireTM
COMMAND is able to interface with all modern StarFire receivers over ISOBUS/CANBUS for position feedback, including StarFire 3000, 6000, 7000 & 7500 models.
Differential GNSS or SF corrected signals e.g. SF3 are NOT considered suitable for implement position feedback as position accuracy and repeatability are insufficient.
Compatible Cross-slope / Roll / Tilt Sensors
For users making use of Cross-slope control using the COMMAND ECU's second output function, we recommend the use of the T3H-E003 COMMAND Inclination Sensor – TARS-B to ensure that the angle sensor being used is robust and accurate for automatic implement control.
T3H-E003 - COMMAND Inclination Sensor
A TARS-B inertial measurement unit configured by T3RRA can be used to provide reliable feedback on the pitch and roll angle of the implement and can be mounted on the scraper for automatic Cross-slope control when using receivers such as Case IH Vector Pro or Trimble NAV 900.
StarFireTM TCM (Terrain Compensation Module)
COMMAND can make use of the in-built StarFire TCM, which provides feedback on pitch and roll angle of the receiver. The StarFire TCM can be selected as a Cross-slope / Tilt sensor but we cannot guarantee the accuracy / bias drift of the sensor and generally recommend the use of T3H-E003 shown above.