The Design And Implementation Of Distributed Micro-Seismic Data Acquisition Node

With the development of science and technology,geophysical exploration technology is getting more and more attention,ecspecially the micro-seismic monitoring technology.As an important safety monitoring method,it has been widely used in many fields such as underground space development,mining,bridge construction,tunnel construction,dammonitoring,underground energy storge and hydrofracturing method energy ming.The microseismic data acquisition node is the key component of the microseismic monitoring system.Its performance,data acquisition quality and synchronization of data acquisition with other nodes have a crucial impact on the location and analysis of microseismic events.At present,the development of micro-seismic monitoring equipment in our country is slow,and most of the instruments rely on the import.Most of the instruments are not only expensive but also have poor versatility for different construction environments.In view of this,it is significant to develop our own micro-seicmic which are high-precision,highperformance,low-cost and versatility.This thesis with Zynq-7000 series FPGA as its dominant component by using the idea of hardware and software collaborative design,presenting a scheme of multi-channel microseismic data acquisition node.The main resesrch contents are as follows: 1?Designed highfidelity signal conditioning circuit,the original signal of the sensor is adjusted by 1~64,and converted into a differential signal to improve the anti-interference ability.2?To meet with requirements of multi-channel parallel acquisition,32-bit high-precision A/D conversion control IP core based on AXI bus is developed by the Vivado platform using the Verilog HDL and top-down design method.This IP core has achived strict parallel synchronous acquisition and sampling channel tailoring and expansion.3?In order to maximize the performance of the chip to obtain the best system control effect,the ARM processor loads the embedded linux operating system,using multi-threaded progarming technology to design the related peripheral driver and application program design under Eclipse platform.4?To ensure that the collected data can be transmitted and stored in real time,efficiently and stably,create data transmission and storage threads respectively.The collected data is stored to an external SD card while being transmitted over long distances via Ethernet based on TCP/IP protocol.At the same time,the mechanism of double-buffer ping-pong operation is adopted in the thread,which avoids the thread scheduling causing an access conflict to the data buffer.5?Setting up an FTP server in embedded Linux facilitates data recovery during debugging.6?In order to achieve synchronous acquisition between multiple nodes,porting the PTP network clock synchronization protocol in the application layer of the embedded Linux system,and adding the PTP protocol patch to the Linux kernel make it to obtain timestamp information at the MAC layer.Compare with the dedicated clock chip design scheme,this design scheme reduces the hardware cost and improves the versatility of the hardware device,and improves the synchronization precision compared with the pure software implementation of the PTP protocol.The experimental results show when input referred noise is less than 3uV,the crosstalk between the channels is up to-115 dB,at the sampling rate of 1ksps.The average synchronization accurcay between nodes reaches sub-microsecond level which satisfies the design requirements.