Calibration of a Multi-sensor Inertial Measurement Unit with Modified Sensor Frame

Calibration of the inertial measurement units (IMU) used in navigation systems are crucial for ensuring accuracy of a navigation solution. It is common to discuss what calibration means, techniques, and algorithms can be utilized and implemented. For cost-effective measurement units it is desirable to use calibration means and approaches which are not expensive yet capable of providing sufficient accuracy. This paper thus focuses on multi-sensor inertial measurement unit which utilizes a modified sensor frames. Unlike the common IMUs which consist of 3-axial accelerometer and gyroscope frames, the proposed concept of the multi-sensor unit consists of ten modified accelerometer frames supplemented by an unmodified gyro frame. The modified frames of accelerometers are optimized for differential analogue signal processing in order to increase signal-to-noise ratio and hence overall sensing precision. Since the proposed concept of the measurement unit includes higher number of sensing frames it is required to develop a novel "easy to do and implement" calibration method which is the contribution of this paper. The proposed calibration approach was experimentally verified and results confirmed its usability.