Fast and precise solving of non‐linear optimisation problem for field calibration of triaxial accelerometer

Abstract

Unlike laboratory calibration methods, filed calibration methods are not time consuming, costly and do not need laboratory equipment, so they can be used in any environment for calibration of low-cost MEMS accelerometers. The magnitude of gravity vector in static state is used as a reference in the calibration process. Then a cost function is defined which is non-linear and complex. So, in order to simplify this equation, a novel change of variables is proposed which converts this non-linear optimisation problem to a linear least square (LLS) method and a non-linear equation solving. After minimisation of this cost function using LLS method, bias, scale factor and non-orthogonality of the accelerometer are estimated and it is compared with two other field calibration methods. The results of simulations show good performance of proposed method. For online estimation of these coefficients, recursive least squares method is also utilised. Finally, simulations in MATLAB have shown that they converge to the true values.