Research Of High-precision Seismic Signal Acquisition System Based On MEMS Accelerometer

Nowadays, the acquisition of seismic data plays a more and more important role inproduction and practice. The applications of collecting seismic data include earthquakeearly warning, seismic exploration and so on. Traditional sensor cannot meet therequirements of high-precision seismic data collecting. While the sensor based on MEMSwith its wide dynamic range, small size and high sensitivity is more suitable for seismicacquisition system.This paper develops a high-precision seismic acquisition system based on MEMSacceleration sensor, and realizes the function of high-precision data acquisition, datastorage and data access. With the algorithm of STA/LTA and fixed-window AIC, thissystem realizes the P-wave detection and evaluation of the arrival time of P-wave. Thedevelopment of seismic data acquisition system includes hardware design and softwaredesign.The hardware part includes design of analog circuit and digital circuit. In analogcircuit, the differential signal conditioning circuit is used to deal with the voltage signal fromsensor, which then will be inputted into the24bits AD converter. In digital part STM32microcontroller is used to drive the TF card circuit and the LCD. In layout design, analogcircuit and digital circuit are isolated in order to decrease the interference form each other.Magnetic coupling is used to isolate the commmunication interface between analog anddigital circuit and the ground of these two parts are connected only in place of systempower.In the software part, under the sampling rate of50Hz the program realizes the displayof real-time seisimic waveform on the LCD, real-time data store in the specific file on the TFcard and data access. The alogrithm part realizes the detection of the arrival of P-wave andthe evaluation of arrival time of P-wave. The major work is as follows.1. This paper designs two different data store modes—Low-power store mode andcontinuous store mode, with both modes10000seismic datas can be collected withsampling interval of20ms and stored in specific file in TF card. These two modes arerealized by different implementation principles and they are suitable for functioning underdifferent conditions.2. This paper designs the data access alogrithm according to the format of the datastored in specific file. 3. This paper uses STA/LTA algorithm to detect the arrival of P-wave. And theoperations including ordered data store and access in the aglorithm are realized by usingcircle buffer. Fixed time window AIC aglorithm is used in order to evaluate more accuratearrival time of P-wave. The result of these earthquake early warning aglorithm is displayedon LCD in real-time manner.The seismic data acquisition system is tested at last. The result shows that incontinnuous store mode the minimum resolution of system is50uv. System is responsiveand the quality of reconstructed waveform on LCD is good. The test result undersimulating environment shows the P-wave detection algorithm functions well. And thisdesign provide a feasible solution for seismic data acquisition system.