GNSS antenna must be fixed with respect to the sensor. It should have a clear view of sky. 

Dual antenna systems considerations

Dual antenna systems installation requires special care in order to obtain optimal performance:

  • Use two antennas of the same type, connected to same cables with identical lengths
  • Both antennas must be turned the same way (connectors or North mark oriented in same direction with respect to the vehicle)
  • Both antennas must have a clear view of sky
    • In case some masks caused by the vehicle cannot be avoided, it should be minimized, and both antenna should share the same masks. In other words, it's important that both antenna see the same satellites.
  • Small patch antennas must be placed on a ground plane, and ideally, more than 20cm away from the ground plane edges

  • The Baseline (distance between two antennas) should be maximized for best performance, although it is possible to operate on short baseline:
    • 30cm will typically lead to sub-degree heading accuracy
    • At least one meter is recommended in manned vehicles (as soon as the vehicle size allows this).
    • 2m or more is recommended for high precision applications

GNSS lever arm measurement

Once installed, both GNSS antenna lever arms must be measured. 

The GNSS lever arm is the signed distance, expressed in the vehicle coordinate frame, FROM the sensor's center of measurement, TO the GNSS antenna phase center. It must be measured within 5cm accuracy.


Dual GNSS antennas installation in the vehicle with corresponding lever arm along vehicle X axis

Dual GNSS antennas installation in the vehicle with corresponding lever arm along vehicle Y axis