Research On Synchronization Method Of Distributed Sensor Acquisition And Transmission System

Distributed sensor acquisition and transmission techniques are widely used in ocean exploration,which requires large-scale and large-range array signal acquisition.In the paper,we perform the research on key technologies of multi-node synchronization acquisition and real-time transmission,and design a distributed sensor acquisition and transmission system based on Gigabit Ethernet.The main clock synchronization and sampling pulse synchronization method between different nodes are studied.A distributed acquisition and transmission system for underwater acoustic signals is designed and implemented.Specific works are as follows:1.Several common distributed sensor acquisition and transmission technologies,such as RS485,LVDS and Ethernet,are discussed in detail,and the characteristics and adaptability of these technologies are analyzed.2.According to the requirement of large scale distributed transmission,a design scheme of distributed underwater acoustic signal acquisition and transmission system based on Gigabit Ethernet is proposed based on the analysis of these factors,such as signal bandwidth,transmission distance,power consumption,cost and so on.A system based on IEEE 1588 PTP for master clock synchronization and inter node sampling pulse synchronization based on SYNC command is proposed.A self-defined protocol stack based on UDP protocol is designed,and the upper computer software adapted to different operating systems is compiled.3.According to the specific requirements of high synchronous acquisition,we analyzes the key factors influencing the performance of synchronization in the system,and puts forward compensation of node master clock synchronization error based on PLL and FPGA frequency division sampling clock generation using internal PLL/DLL.The test results show that the system master clock synchronization accuracy is not more than 10 ns,and the command synchronization accuracy is less than 1 ?s.4.Based on FPGA,as a main chip,the design and manufacture of multi node sensor acquisition and transmission system based on UDP are achieved.The distributed synchronous data acquisition and long distance real time data transmission of large aperture linear array sonar have been realized and applied to the large aperture line array sonar data acquisition and transmission system with scale of 224 elements.