Precise Evaluation of Frequency Response Consistency Between Accelerometers by Exciting With Dual-Frequency Vibration

Nano-gaccelerometers are used in high-precision applications where frequency response consistency across devices can outweigh individual calibration accuracy. In scenarios such as gravity gradient measurements on moving-platforms, strong motion disturbances make this consistency assessment and compensation essential, yet challenging with conventional methods. This paper proposes a method of precisely evaluating accelerometer frequency response consistency (FRC) by introducing an auxiliary reference frequency in addition to the test frequency. Two accelerometers are excited side by side during the sweep test. Systematic analysis indicates that it can significantly suppress dominant common-mode errors which result from the test apparatus, the monitoring instruments, the accelerometer under test and the susceptibility of them to the environmental conditions in such an FRC test. Experimental results demonstrate that the proposed method yields substantially more precise evaluation of the FRC than individually testing every accelerometer. A compensation filter is accordingly designed to correct the inconsistency between two self-developed accelerometers, improving amplitude consistency to better than 10 ppm and phase consistency to better than 10 μrad.