Abstract：A series of vibration tests with different frequencies are conducted on a shake table to clarify the characteristics of low-frequency measurement. We analyze the results from two aspects: power spectral density of acceleration and displacement derived from integration of acceleration. We find that accurate displacement can be recovered by double-integration of acceleration(with appropriate high-pass filtering) on the condition that the frequency of vibration signal is above 0.05 Hz. In order to recover accurate displacements of vibration signals, especially in low frequency, we combine GNSS and accelerometer. The results show that this shake table system is an appropriate platform for earthquake monitoring studies; the lower limit of accelerometer low-frequency measurement is around 0.03-0.05 Hz, and the result provides reference for the proper choice of cut-off period for data processing of accelerometers as well. Meanwhile, the data fusion of GNSS and accelerometer data can combine the strength of each instrument and make the displacement derived more accurate and reliable.
LI Chenghong,LI Tao,LI Guangcai et al. Low-Frequency Signals Measurement Characteristics of Accelerometers and Its Combination with High-Rate GNSS for Earthquake Monitoring[J]. jgg, 2019, 39(12): 1293-1298.
