  This paper presents an efficient in-field calibration method tailored for
low-cost triaxial MEMS gyroscopes often used in healthcare applications.
Traditional calibration techniques are challenging to implement in clinical
settings due to the unavailability of high-precision equipment. Unlike the
auto-calibration approaches used for triaxial MEMS accelerometers, which rely
on local gravity, gyroscopes lack a reliable reference since the Earth's
self-rotation speed is insufficient for accurate calibration. To address this
limitation, we propose a novel method that uses manual rotation of the MEMS
gyroscope to a specific angle (360{\deg}) as the calibration reference. This
approach iteratively estimates the sensor's attitude without requiring any
external equipment. Numerical simulations and empirical tests validate that the
calibration error is low and that parameter estimation is unbiased. The method
can be implemented in real-time on a low-energy microcontroller and completed
in under 30 seconds. Comparative results demonstrate that the proposed
technique outperforms existing state-of-the-art methods, achieving scale factor
and bias errors of less than $2.5\times10^{-2}$ for LSM9DS1 and less than
$1\times10^{-2}$ for ICM20948.
