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    BMI088 bias jump around 0dps

    BMI088 bias jump around 0dps



    I am evaluating BMI088 for navigation applications.

    I need to verify the gyro nonlinearity error within a relatively small angular range (-10dps to +10dps).

    The test was done in the following steps.

    1. The sensor was fixed on a rate table. The rate table rotated from -10 dps to 10 dps with a step of 0.1 dps. The rate table stayed at each step for 12s.
    2. Collect gyro output when the rate table stayed at constant angular rate, and the gyro output was averaged to remove noise.
    3. Compare the Z axis gyro output with the rate table set rate.

      3.1 The gyro output was first calibrated using best fitting straight line to correct scale factor and bias error.

      3. 2 The calibrated gyro output at each step was compared with the set value to calculate the error which is considered as nonlinearity.

    4. The test was repeated for three times.

     We can clearly see that when the rate table rate crosses 0dps, there is a jump in the gyro output.  We tested a few units and all the units show similar behavior.

    It seems there is some ADC error. Could any one help to explain and provide some kind of configuration to fix this? Thank you.

    nonlinearity errornonlinearity error




    12 REPLIES 12

    Community Moderator
    Community Moderator

    Hello dxglaw,

    Is your rate table a standard test tool?

    Hello BSTRobin,

    Yes, it is a standard tool and should be accurate enough.

    Actually, we simultaneously tested many types of IMUs including BMI088 and BMI160. All other units seem fine.

    BMI160 also has nonlinearity issue, but different from BMI088. Please see fig below. However, since we will not use BMI160 in navigation application, I didn't include this in the original post.


    As a comparison, I also provided results from another low-cost IMU.



    Community Moderator
    Community Moderator

    Hello dxglaw,

    In order to evaluate the nonlinearity (error) value of BMI088, could we now what gyroscope range you set?

    BMI088 gyroscope range.png

    Hi BSTRobin,


    The FSR is 500 dps. I believe the nonlinearity error should be well with in spec because integral nonlinearity is specified here.


    However, the issue I mentioned seems a systematic error and should be able to be fixed.