  The calibration of MEMS triaxial gyroscopes is crucial for achieving precise
attitude estimation for various wearable health monitoring applications.
However, gyroscope calibration poses greater challenges compared to
accelerometers and magnetometers. This paper introduces an efficient method for
calibrating MEMS triaxial gyroscopes via only a servo motor, making it
well-suited for field environments. The core strategy of the method involves
utilizing the fact that the dot product of the measured gravity and the
rotational speed in a fixed frame remains constant. To eliminate the influence
of rotating centrifugal force on the accelerometer, the accelerometer data is
measured while stationary. The proposed calibration experiment scheme, which
allows gyroscopic measurements when operating each axis at a specific rotation
speed, making it easier to evaluate the linearity across a related speed range
constituted by a series of rotation speeds. Moreover, solely the classical
least squares algorithm proves adequate for estimating the scale factor,
notably streamlining the analysis of the calibration process. Extensive
numerical simulations were conducted to analyze the proposed method's
performance in calibrating a triaxial gyroscope model. Experimental validation
was also carried out using a commercially available MEMS inertial measurement
unit (LSM9DS1 from Arduino nano 33 BLE SENSE) and a servo motor capable of
controlling precise speed. The experimental results effectively demonstrate the
efficacy of the proposed calibration approach.
