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I noticed that if I call the startDeviceMotionUpdates method of the CMMotionManager class and then rotate the device and put it back on the table the reported device attitude is changing constantly, every time the reported rotation matrix is different from the last time. Has anyone else noticed the same behavior ?

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How different is each successive matrix? –  Lou Franco Apr 20 '12 at 15:51
@Lou It shows about 10 degrees of rotation around z axis when being still on the table in 2 minutes with update rate of 100 Hz. –  sadegh Apr 20 '12 at 15:57
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Do you have a link to any file or reference which might be useful backing up your answer? –  C4 - Travis Apr 22 '12 at 20:03
@C4-Travis no specific link, but you can search for intertial navigation systems and their errors, and the fact that from time to time they need to be checked with an external source. I noticed the drift is only occuring in yaw component and I'm trying to fix it by taking into account the magnetic field that is an external source. –  sadegh Apr 23 '12 at 4:06
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