Calibration of Accelerometers for the Measurement of Microvibrations

摘要

The accelerometers used for the measurement of microvibrations or microgravity applications, such as active control of space structures, attitude control, scientific payloads, or even on-Earth testing of structures at very low-excitation levels, require a dedicated calibration procedure that includes the gravitational effects. Otherwise, on-Earth calibrations can be inaccurate due to the collateral projection of the local gravity onto the sensitive axis. An on-Earth calibration technique for the 10~(-7)-10~(-2)-g amplitude range and 0-100-Hz frequency range is described. Special attention has been given to the modeling of gravitational effects on the response of the calibration device and the accelerometer itself. The sensitivity and resolution tests performed on piezoelectric accelerometers show the accuracy and the potential of this technique. Typical scale factor uncertainty, which has been carefully analyzed, is of the order of 2% at acceleration levels of 10~(-5) g.