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Difference between revisions of "Compass"


(Compass Calibration)
(Characteristics)
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== Characteristics ==
 
== Characteristics ==
  
      • Provides orientation in world coordinate system.
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* 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.  
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* 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.  
        In the presence of strong magnetic fields orientation estimation is unusable.  
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* Pose estimation suffers from noticeable jitter if Compass is used as the only orientation source.
      • Pose estimation suffers from noticeable jitter if Compass is used as the only orientation source.
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* The orientation is updated with roughly 250Hz.
      • The orientation is updated with roughly 250Hz.
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* Orientation estimation is not responsive and suffers from noticeable delays.
      • Orientation estimation is not responsive and suffers from noticeable delays.
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* Requires accelerometer and magnetometer.
      • Requires accelerometer and magnetometer.
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== Compass Calibration ==
 
== Compass Calibration ==

Revision as of 13:12, 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.