GNSS Antenna Lever Arm Offsets

The purpose of lever arm offsets are to transfer the position received at the GNSS antenna, to the camera sensor. This article explains how these measurements are referenced in ASPSuite. If you are using an AirGon supplied antenna mount, the default offsets in ASPSuite should be used.

  • Z Offset
    • Starts at antenna phase center (3 cm above the base of the antenna, not the base of the ground plane) and is positive down to the camera sensor.
    • For Inspire 2, M200/ 210, and P4P users, measure to the pivot point of the gimbal.
    • For DSLR users, measure to the focal plane mark on the camera and add the length of the lens being used (ex. 28mm lens = .028m from focal plane to nodal point)
    • Be sure the camera is in the same position as it will be when flying a mission.
  • X Offset
    • The X offset is aligned with the heading of the aircraft and should be measured to the center of the camera sensor.
    • The X offset is positive if camera center is forward of the GPS antenna. The offset is negative if camera center is behind the GPS antenna.
  • Y Offset
    • The Y offset is perpendicular to the heading of the aircraft and should be measured to the center of the camera sensor.
    • The offset is positive if the camera is right of the antenna. The offset is negative if the camera is left of the GPS antenna.
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