Triaxial Accelerometer Static Calibration

A new approach is studied to calibrate a low-cost, microelectromechanical system (MEMS) triaxial accelerometer. The accelerometer is modeled as a linear system with inter-axis misalignment correction. Mathematically, at least nine different equations, equivalent to nine positions of an accelerometer, are needed to solve for nine unknowns (3 scale factors, 3 zero bias, 3 misalignment angles). However, a new approach is studied to minimize the number of positions needed. Three new linear equations corresponding to each axis are formulated. To validate the equations, a triaxial accelerometer was positioned at twelve known orientations and its outputs were measured. All possible combination of positions were attempted iteratively. Singularity is identified using the principle of matrix rank. Results from twelve positions and six positions were almost identical, suggesting that six positions are adequate to solve nine unknowns.