The Design Of Electromagnetic Data Acquisition Instruments For Marine CSEM Prospecting

With the rapid development of economy, human relying on the earth’s resourcesis increasing day by day. Resources on land have been unable to meet the needs thehigh-speed development of the economy. Because of its huge economic potential,more and more countries pay more attention to the marine resources. Especially inChina’s demand for energy is rising year by year. The energy crisis has affected thecountry’s economic stability and sustainable development. Developing theelectromagnetic data recorder system with independent intellectual property rights isan important measure to enhance the seabed resource exploration capacity. Thissubject originates from the development and research of system equipment marinecontrolled source which belongs to the National High-Tech Research andDevelopment Program (863Torch Program)(2012AA09A201) and Research on thekey technology of the deep-sea observation systems which belongs to ShandongProvince Science and Technology Development Program (2011GHY11535).Combining with the project in the process of research and development technicalaccumulation, with ultra-low noise, low frequency chopper amplifier and highprecision, low drift clock technology for the protection, the design of high precision Σ-Δ A/D converter and FPGA+ARM technology to complete the electromagnetic datarecorder system with high resolution, low noise, low frequency weak signalamplification.This paper mainly research on electromagnetic data recorder data acquisitionstation. Electromagnetic data recorder is applied to amplify the signal ofelectromagnetic sensor which receives back. Then recorder is synchronized a pluralityof Σ-Δ ADC by using the technology of FPGA. The collected data is passed to theARM by using the FSMC bus. Data is stored to CF card by using the ARM withFATFS file system. This design integrates the low noise frequency chopper amplifier,programmable amplifier, multiple sampling rate of24Σ-Δ ADC, high reliability ofdata storage. Recorder synchronous acquisition between more than one collectionstations with high precision clock control unit. Data recorder system improve the dataprocessing speed and accuracy, optimize the whole system hardware circuit designwith using FPGA as the core of the digital design.In this paper, the design of the whole system makes detailed theoretical analysis and completes the software and hardware design from the topic research significance,the domestic and foreign research dynamic, implementation methods and technicalaspects. Thesis mainly made the following findings: Completed the hardwareschematic design of electromagnetic data recorder, processed into PCB and completedthe debugging of hardware circuit, using Verilog HDL language completed control ofthe FPGA logic design and completed the simulation demonstrate, finished alldesigned and completed the debugging of the software based on ARM platform. Thealignment of the whole system and did a series of tests in the field to complete theperformance of the project is put forward.The main innovative system design: the digital logic design method based onFPGA, decreases in the aspect of hardware circuit design, save the cost and improvethe real-time performance and reliability of the system, and the software part is easyto the simulation and test, using high precision of24for Σ-Δ ADC improves theresolution of data gathering and dynamic range, design a set of intelligent powermanagement system, effectively reduce the power consumption of the system. Usingclock calibration system for high precision clock calibration temperaturecompensation module, improves the precision of the clock.