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    BNO055 calibration routine values

    BNO055 calibration routine values

    New Poster

    Hey everyone!

    I'm working on a university project using BNO055 in order to come up with a filter algorithm for MEMS IMUs. I recorded some data while the chip lay exactly horizontal on the ground as to examine the remaining offsets after the calibration routine and found small offsets (~ 0.2 m/s^2). As I'm trying to find the "true" offset, I would like to get the raw, uncalibrated accelerations out of my data. I saved the calibration profile for each of my experiments, but I'm not sure as how to interpret the numbers given in the calibration profile. For example, I have  "calibrationData.accel_offset_x = -21", what does the -21 mean? Is it maybe bits in relation to the sensitivity given in the data sheet? 

    Also, I was wondering if you could give my any more information about how the calibration algorithm in the firmware works exactly?

    And, last but not least: Can you tell me how to interpret the "radius" parameter in the calibration profile?

    Thanks in advance!


    3 REPLIES 3

    Community Moderator
    Community Moderator

    Hello LouisaG,

    Ideally, the offset of the x-axis is 0. The actual output will be different from the ideal case, - 21 is the difference between and 0.

    Usually, after the calibration is successful, read the profile and save it, and write the profile when necessary.

    BNO055 reuse of calibration profile.png

    Hello BSTRRobin,

    thanks for your answer. I'm aware that the actual output will never be the ideal value - that's why the sensors need calibration after all. Unfortunately, the screenshot from the manual doesn't help me with my problem. 

    I've conducted several experiments with different calibration routines. Now I want to compare the data and the offsets from the experiments, therefore I need to know how to translate the offset values given in the calibration profile (e.g. -21) to values in m/s^2 for the accelerometer or deg/s for the gyro. Where can I find this conversion factor?

    Community Moderator
    Community Moderator

    Hello LouisaG,

    You could see accel, gyro data conversion in BNO055 data sheet "3.6.4 Sensor calibration data".


    BNO055 ACC unit settings.png


    BNO055 GYRO unit settings-1.png

    BNO055 GYRO unit settings-2.png