Improving Gyroscope’s Noise Performance By Embedding it in a Closed-Loop Involving Multiple Accelerometers

Abstract

This work introduces an inertial measurement unit (IMU) architecture which combines several three-axis accelerometers and a three-axes gyroscope to provide an increased accuracy, low-noise measurement of the angular velocity. This is an extension of gyroscope-free IMUs, which use only accelerometers to measure the linear acceleration and translate it to angular velocity by solving a system of differential equations. Existing architectures cannot compensate for the accelerometers’ bias which integrated is translated to a constant drift of angular velocity. The proposed system exploits the basic operating principles of the gyroscope-free IMUs and uses a three-axis gyroscope in a closed-loop configuration to compensate for the effect of the accelerometers’ bias. Focusing on a very popular and highly cited IMU, the stability of the proposed system is proved analytically. Simulation results indicate that the proposed architecture excels in terms of noise performance; in the upper frequency range, it presents up to 30dB less noise at its output compared to the gyroscope.