Using Blue Tridents with Nexus

Check out the Official Vicon Blue Trident support documentation for everything you need to collect your IMU data in Nexus.

Capture Rates and Data Options

The capture rate of your IMU data is dependent on the type of data you are recording and the number of sensors being used.

  • Nexus will automatically adjust the streaming data rate to the maximum possible with the options you choose and with how many sensors you connect; the onboard data capture rate is not affected by number of sensors connected to the system
  • Nexus supports the use of up to 18 Trident IMUs
  • Blue Tridents have a variety of collection modes, including 15-axes (Acc, Gyro, Mag, HighG Acc, Global Angle):

There are also two sampling rates you need to be aware of when recording Trident IMU data via Nexus. The sensors live stream data at a reduced sample rate for immediate viewing and any real-time processing that is desired, and simultaneously store data onboard at maximum sample rate for later download.

The lower live streaming rate is due to Bluetooth bandwidth limitations, the Tridents simply produce too  much data for it to all be streamed over a Bluetooth protocol. Here are some example sample rates as listed by Vicon:

  • If Global Angle is selected (fifteen axes)
    • Onboard capture rate is 225 Hz, live stream is 30 Hz
  • If Global Angle is cleared (only sensor raw data recorded – twelve axes)
    • Onboard capture rate is 1125 Hz, live stream is 30 Hz;
  • If  no HighG or GlobalAngles are selected (Nine axes)
    • Onboard capture rate is 1125 Hz, live stream is 50 Hz;
  • If HighG only is selected (three axes),
    • Onboard capture rate is 1600 Hz, live stream is 100 Hz.

Data Synchronisation

See the Official Vicon Documentation on this subject here.

The Trident IMUs are synchronised through Nexus in one of two ways:

  • Via Bluetooth – a ‘soft sync’ option, best used when the sync with other sensors/data doesn’t need to be millisecond precise. This option requires only Bluetooth connectivity, though we recommend a Bluetooth USB dongle and a USB extender to increase range and signal strength rather than your PC/laptops inbuilt functionality.
  • Via a Vicon Beacon (radio sync) – ‘hard sync’ option to sync precisely using the Vicon timecode. Requires a Vicon Beacon  – please contact us if you are interested in pursuing this option.

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