海洋实时电磁探测采集系统设计

Design of real⁃time electromagnetic detection and acquisition system for marine

海洋电磁探测是水下目标非声探测的研究热点。针对水下目标电磁探测的实时计算和高速传输需求,提出一种基于SoC FPGA的海洋实时电磁探测采集系统(ROEM/SoC FPGA)。系统主控采用内嵌ARM Cortex⁃A9处理器的SoC FPGA,包括HPS端和FPGA端。HPS端搭建基于嵌入式Linux操作系统的系统软件,实现多通道电磁数据的时频分析和实时传输,时频分析采用短时傅里叶变换方法,实时传输采用基于MQTT和TCP/IP的网络传输;FPGA端搭建数字逻辑实现多通道电磁数据同步采集;FPGA端与HPS端通过AXI总线互联。与传统的“低功耗MCU+FPGA”电磁探测采集系统相比,具有较强的数据实时计算和传输能力,测试结果表明,设计的ROEM/SoC FPGA系统能够有效完成多通道电磁数据的时频分析和网络传输,对采样率为125 Hz的10 min单通道电磁场数据的时频分析计算耗时约为2634 ms,网络传输速率可达14.5 MB/s,可以满足水下目标电磁探测的应用需求。

Marine electromagnetic detection is a research hotspot of underwater target non⁃acoustic detection.A marine real⁃time electromagnetic detection and acquisition system based on SoC FPGA(ROEM/SoC FPGA)is proposed for the real⁃time calculation and high⁃speed transmission requirements of underwater target electromagnetic detection.SoC FPGA with embedded ARM Cortex⁃A9 processor is used for the main control of the system,including HPS(hardware processor system)terminal and FPGA terminal.At the HPS terminal,system software based on embedded Linux operating system is built to realize time⁃frequency analysis and real⁃time transmission of multi⁃channel electromagnetic data.The short⁃time Fourier transform method is adopted for the time⁃frequency analysis,and network transmission based on MQTT(message queuing telemetry transport)and TCP/IP is adopted for the real⁃time transmission.At the FPGA terminal,digital logic is built to realize the synchronous acquisition of the multi⁃channel electromagnetic data.The FPGA terminal and HPS terminal are connected by AXI bus.In comparison with the traditional electromagnetic detection and acquisition system″low⁃power MCU+FPGA″,the designed system has stronger real⁃time data calculation and transmission capabilities.The test results show that the designed ROEM/SoC FPGA system can effectively complete the time⁃frequency analysis and network transmission of multi⁃channel electromagnetic data.The time⁃frequency analysis and calculation of 10 min single⁃channel electromagnetic field data with a sampling rate of 125 Hz takes about 2634 milliseconds,and the network transmission rate can reach 14.5 MB/s,which can meet the application requirements of underwater electromagnetic detection.