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Low-cost Calibration of Inertial Measurement Unit for Accurate Position Estimation

This paper presents a low-cost calibration method for inertial measurement units (IMU) to accurately estimate their orientation, velocity and position. A general purpose IMU measures the specific force and angular velocity but suffers from bias, nonlinearity, and non-orthogonality, thus leading to large errors. Conventional calibration methods require expensive reference platforms and high-end calibration sensors. The low-cost calibration method developed in this paper requires no additional equipment but a series of measurements with the IMU sensor briefly resting on different orientations. A new post-measurement signal processing method is then proposed to calibrate the IMU sensor which achieves an order of magnitude better accuracy in position estimation. The new method is implemented in a small data logger housed in a sphere with 20 mm diameter.