ESTIMATION OF UNCERTAINTY CONTRIBUTION OF TRANSVERSE SENSITIVITY AND VIBRATION DISTRIBUTION ON PRIMARY ACCELEROMETER CALIBRATION

摘要

Primary accelerometer calibration is carried out under the assumption that a vibration exciter gives a rectilinear motion to an accelerometer to be calibrated. However practical vibration given by the vibration exciter includes parasitic motion such as transverse, rocking, and bending motion. The parasitic motion especially gives two serious effects on primary calibration results, transverse sensitivity effect and vibration distribution effect. Transverse sensitivity effect is caused by an inner product of the vectors of both transverse motion and transverse sensitivity. On the other hand, the vibration distribution effect is caused by motion disturbance and relative difference between acceleration at sensing point of accelerometer and at the spot sensed by the interferometer. These uncertainty sources have close interaction between vibration exciter and accelerometer, and close interaction between vibration exciter and the laser interferometer, respectively. Therefore, it is very difficult to estimate independently their uncertainty contribution. In this study, we propose simple methods to estimate uncertainty contribution due to these effects in the primary calibration, respectively. The proposed methods would enable more practical estimation of uncertainty budget.