Difference between revisions of "Compass"

Revision as of 11:49, 19 September 2017

The Compass internally utilizes the accelerometer and magnetometer to estimate the device orientation in relation to the magnetic north. As the compass is vulnera-ble to external influences, it is recommended to disable the Compass in the pres-ence of strong magnetic fields.

Characteristics

      •	Provides orientation in world coordinate system.
      •	The error in orientation estimation is characterized by an offset between real and estimated device orientation. Typically an accuracy of 10-20° is achieved. 
        In the presence of strong magnetic fields orientation estimation is unusable. 
      •	Pose estimation suffers from noticeable jitter if Compass is used as the only orientation source.
      •	The orientation is updated with roughly 250Hz.
      •	Orientation estimation is not responsive and suffers from noticeable delays.
      •	Requires accelerometer and magnetometer.

Compass Calibration

To compensate the offset between real and estimated device orientation, the com-pass offset can be calibrated, by one of these three mechanisms:

      •	Manually specify the compass offset in the Settings.
      •	Once the Compass Calibration Button in the POI View is clicked, the Compass will behave as if the current heading was north.
      •	Once an AR-Marker used for device pose estimation is scanned, the Compass offset is automatically calibrated.