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GNSS

Updated on Mar 13, 2026

The GNSS menu in VBOX Setup, connected to a VBOX 3iS Dual Antenna RTK, contains GNSS receiver information and provides the ability to set the dynamic mode, DGNSS mode, leap second, elevation mask and to perform a GNSS coldstart. From the GNSS menu, you can also configure the Dual Antenna settings. 

VBOX Setup - VB3iSDR - GNSS - Settings

Under this area, you can view information about the GNSS receiver and perform a GNSS coldstart. More information on GNSS coldstart is available here.

The leap second value can be changed if required. This was increased to 18 seconds as of December 2016 - more information on this is available here.

Allows you to change the elevation mask, selectable from 10 – 25° (10° by default). If the testing area has nearby trees or buildings, you may benefit from increasing this value to reduce the effect of multipath. More information on this is available here.

Note: Increasing this value will reduce the number of satellites the VBOX will be able to use.

VBOX Setup - VB3iSDR - GNSS - Settings_Optimisation (Cropped)

This option allows you to change the sensitivity of the GNSS engine.

  • High dynamics (default) - For high dynamic applications such as brake stop testing.
  • Medium dynamics - Suitable for all other testing.
  • Low dynamics - For less dynamic applications, such as steady state speed measurement or coastdown testing. 
VBOX Setup - VB3iSDR - GNSS - Settings - DGNSS Mode (Cropped)
VBOX Setup - VB3iSDR - GNSS - Settings - DGNSS Mode_Baud Rate

This option allows you to select whether the VBOX 3iS uses differential GNSS. Use the drop-down menus to select the desired mode and baud rate.

  • Mode  - lets you select the desired
    • None (default) - Differential GNSS is off.
    • CMR (2 cm RTK) - 2 cm correction (Trimble standard message type).
    • RTCMv3 (2 cm RTK) - 2 cm correction (RTCM standard message type). This is the recommended setting.
    • NTRIP - Internet-based subscription service, more information on this can be found here.
    • MB-Base - Mode for use in Moving Base ADAS applications.
    • MB-Rover - Mode for use in Moving Base ADAS applications.
    • RTCM (40 cm) - the VBOX 3iS receives RTCM corrections via a Racelogic telemetry module and a locally placed Base Station. Contact Racelogic or your local agent for more details.
    • SBAS - SBAS differential corrections are received from the nearest Geo-stationary GPS-SBAS satellite.
       
  • RS232 baud rate - Sets the DGNSS serial rate, and is available to select when a DGNSS mode option other than None is selected. To ensure that the VBOX 3iS receives the DGNSS correction signal, the correct RS232 baud rate must be set. All Racelogic blue-boxed radios use 115200 kbit/s, Satel grey-boxed radios use either 19200 kbit/s or 38400 kbit/s.
 

This area is used to configure the Dual Antenna mode of VBOX 3iS.

VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled

 

Dual Antenna
Enable or disable Dual Antenna mode.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled (Cropped)
Antenna Separation
Apply an antenna separation distance.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_Antenna Separation (Cropped)
Orientation
Switch between Pitch and Roll measurements during testing.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_Orientation (Cropped)
Centre of gravity slip offset
Configure the slip translation offset from the centre of gravity point for the vehicle to the GNSS antenna.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_COG OffSet (Cropped)
Front left slip offset
Configure the slip translation offset from the front left reference to the GNSS antenna.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_FL Offset (Cropped)
Front right slip offset
Configure the slip translation offset from the front right reference to the GNSS antenna.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_FROffset (Cropped)
Rear left slip offset
Configure the slip translation offset from the rear left reference to the GNSS antenna.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_RL Offset (Cropped)
Rear right slip offset
Configure the slip translation offset from the rear right reference to the GNSS antenna.
VBOX Setup - VB3iSDR - GNSS - Dual Antenna - Enabled_RR Offset (Cropped)
 

This area is used to set non-standard settings in the GNSS engine. This should only be used under advice from a Racelogic support technician.
 

VBOX Setup - VB3iSDR - GNSS - Engineering Diagnostics (Cropped)