Sensor Orientation

By default, the PX4 should be oriented such that the arrow labeled “front” is on top and pointed toward the front of the airframe. Sometimes however it is necessary to mount the board in a different orientation, for example: upside down. In this case it is necessary to inform the firmware of the non-standard orientation. This is may be done with the following parameters.

SENS_BOARD_ROT

This parameter defines the rotation of the FMU board relative to the platform. Possible values are:

  • 0 = No rotation
  • 1 = Yaw 45°
  • 2 = Yaw 90°
  • 3 = Yaw 135°
  • 4 = Yaw 180°
  • 5 = Yaw 225°
  • 6 = Yaw 270°
  • 7 = Yaw 315°
  • 8 = Roll 180°
  • 9 = Roll 180°, Yaw 45°
  • 10 = Roll 180°, Yaw 90°
  • 11 = Roll 180°, Yaw 135°
  • 12 = Pitch 180°
  • 13 = Roll 180°, Yaw 225°
  • 14 = Roll 180°, Yaw 270°
  • 15 = Roll 180°, Yaw 315°
  • 16 = Roll 90°
  • 17 = Roll 90°, Yaw 45°
  • 18 = Roll 90°, Yaw 90°
  • 19 = Roll 90°, Yaw 135°
  • 20 = Roll 270°
  • 21 = Roll 270°, Yaw 45°
  • 22 = Roll 270°, Yaw 90°
  • 23 = Roll 270°, Yaw 135°
  • 24 = Pitch 90°
  • 25 = Pitch 270°

Fine Tuning

The orientation may also be fine tuned to correct for sensor board misalignment or minor calibration errors. Tuning using the following parameters is preferable to using the transmitter's trim controls for correcting persistent drift bias often seen in multirotors. The X,Y and Z axes are fixed relative to the board itself. As seen in the diagram, rotating the board will change their orientation with respect to the airframe's Roll, Pitch, and Yaw axes.

The two rotations are applied consecutively (SENS_BOARD_ROT and this rotation). The values here therefore define a rotation by a delta defined in the NED frame.

SENS_BOARD_X_OFF

Rotation, in degrees, around PX4FMU's X axis. The axis directions are printed on the board itself.

SENS_BOARD_Y_OFF

Rotation, in degrees, around PX4FMU's Y axis. The axis directions are printed on the board itself.

SENS_BOARD_Z_OFF

Rotation, in degrees, around PX4FMU's Z axis. The axis directions are printed on the board itself.

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