Why Do Gyroscopes Drift?

The gyroscope drift is mainly due to the integration of two components: a slow changing, near-dc variable called bias instability and a higher frequency noise variable called angular random walk (ARW). These parameters are measured in degrees of rotation per unit of time. The yaw axis is most sensitive to this drift.

What is gyro drift?

the movement of the axis of rotation of a spinning body around another axis, outside the body and at an angle to it: an effect exhibited by a spinning top or gyroscope.

Why does an IMU drift?

The IMU orientation is usually obtained by integrating the angular velocity measured with the gyroscope [6,11,13,14,15,16,17]. This allows for immediate detection of orientation changes but leads to a drift of the estimated orientation over time, e.g., due to gyroscope bias [18].