Noise reduction of calibration system for micro-vibration measurement

Abstract Micro-vibration is an important measurement target in various fields, such as infrastructure health monitoring or satellite operation. In this study, the effect of background noise in calibrating vibration sensors at small amplitudes is discussed. The primary noise sources in the calibration system are the seismic vibration, self-noise of the laser interferometer, and cyclic error. A vibration isolation system was introduced, and the laser interferometer was replaced to reduce the noise sources. These upgrades reduced the background noise down to 10−7 (m/s2)/Hz1/2 around 10 Hz. Using the system, a servo accelerometer was calibrated with an acceleration amplitude of 0.01 m/s2. The calibration repeatability below 0.1% for the sensitivity was achieved between 0.4 Hz and 100 Hz.