Is it possible to have an IMU with .01 tracking accuracy


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    The specification of 0.01 degree of IMU accuracy is unachievable in a head-mounted form factor. There is no IMU on the market that can achieve this. Further, I think it is important to point out that all IMUs drift over relatively short periods of time. That means from the moment you start tracking head position with the IMU, it is going to start drifting. There is no calibrating away this drift completely, it is a fundamental principle of IMUs. This is why AR/VR headsets have tracking cameras, tracking algorithms such as VIO or SLAM, or other reference points to help eliminate drift. The higher performance the IMU we use, the less drift it will have but they will all drift.

    For example, let’s say you have a perfect digital model of your car displayed in the glasses. The car is parked 100m away from you and you line up the model over the top of the car perfectly in the display. If you are only relying on the IMU to track head rotation then initially, as you rotate your head and come back the car would line up. But over a few minutes the car and image would start to misalign. It is up to the application designer to implement an appropriate tracking algorithm to compensate for this, for example tracking landmarks or features with a camera.

    IMU Selection for this program

    a couple options are: an IMU with integrated GPS and a standalone digital compass.

    IMU + GPS Specifications

    This unit costs approximately 3,000USD. It has a compass Heading Accuracy (with GPS) of 0.15 – 0.3 degrees. The dynamic Pitch & Roll accuracy is 0.03 degrees. The in-run bias is 5-7 degrees per hour.

    Digital Compass with IMU

    The digital compass should be less expensive, an estimate of about 800USD. It has a heading accuracy without GPS of 0.25 degrees and what they call a tilt accuracy of 0.1 degrees. They do not specify in-run bias, but assume it is worse than the previous option.

    Low Cost Comparison

    To give another example, the lower cost very small IMUs that we are integrating into our products have a dynamic accuracy of 2-7degrees for rotation.