Calibrating a 3-Axis Accelerometer Instrument with a Less Accurate Calibration Device: Part 2

This paper is Part 2 of Reference 1. Reference 1 described a full model for the calibration device (CD) and an ideal model for the 3-axis accelerometer instrument (3xAI), with the purpose of showing how the residual misalignments in the CD are transferred to the instrument coefficients when using the conventional calibration methods. In addition, it showed a method to potentially eliminate this transfer by using symmetrical calibration points with additional mounting orientations, regardless of the alignment state of the CD. This paper expands on Part 1 by showing a new math model for the instrument that is congruent with the physics of the measurements, and a very good approximation for the CD equations. With these new models, it is possible to obtain the instrument coefficients with algebra rather than curve fitting. This new method shifts the importance from knowing the angle input to high accuracy in conventional calibrations, to the importance of repeating the same angle setpoints (regardless of the CD misalignments) for each of the instrument mounting orientations.