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RACELOGIC Support Centre

4.2 GNSS – VBOX Setup with VBOX 3iS Single Antenna RTK (v1)

The GNSS menu in VBOX Setup, connected to a VBOX 3iS Single 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.

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GNSS Information 

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

GNSS Settings 
Leap Second

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.


Elevation Mask

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.

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GNSS Optimisation

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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. 

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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.

Engineering diagnostics

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.

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