Systematic calibration method for the nonlinear coefficients of triaxial accelerometers

A novel nonlinear model of triaxial accelerometers is proposed to conveniently compensate the squared and cross-coupling errors. On the one hand, the error effect on the alignment performance which is caused by the parameter alteration of accelerometers can be ignored. On the other hand, the relative precise attitudes can be obtained by laser gyroscopes. Consequently, a systematic calibration method for the accelerometer parameters is designed where no precise inertial setup is needed. First, the specific force measurement errors of triaxial accelerometers caused by the parameter alteration are sufficiently observed by a multi-rotation scheme on a three-axis turntable. Second, the observed quantities are selected as two parts, named as the specific force difference between the adjacent positions in the horizontal channel and the residual gravity in each vertical channel. Then a linear observation equation as the alteration of scale factors, misalignments, biases, squared coefficients and cross-coupling coefficients is established. Due to the deficiency that the systematic calibration method is closely related to the attitude errors, the sensitivity property of parameter estimation accuracy as different levels of attitude errors is also analyzed. The simulation results illustrate that the relative estimation errors are less than 1% on the condition that the attitude errors are less than 1 arc-min. This proves the effectiveness of the proposed systematic calibration method.