Design And Implementation Of The Signal Generator Of IFTEM Type Time-domain Fixed-wing Airborne Electromagnetic System

The time-domain fixed-wing aircraft electromagnetic method is based on fixedwing aircraft as the carrier, in flight process, through the transmit coil around theaircraft producing a large launch magnetic coil, stimulate the earth to produce asecondary induction field, and then using the electromagnetic field theory to explainthe secondary field response to get the geological structure of the body informationhundreds of meters depth.After half a century of development, foreign time-domainfixed-wing airborne electromagnetic method and the instrument system has becomemature, The method have achieved a good application in Census of metal ore body,alarge area of geological mapping, the field of hydrogeology, engineering geology,exploration and environmental monitoring, but the domestic fixed-wing airborneelectromagnetic method and the instrument has been lagging development.In1970s,Changchun College of Geology,Heilongjiang Geological Bureau and other unitsresearch and develop the first set time-domain airborne electromagnetic system-M-1induction pulse transient airborne electromagnetic instrument,In1977,the instrumentwas through a national identification, due to various reasons, the system has not beenable to put into actual production, Later country has not been carried out relatedresearch, So far our country still does not have a time-domain fixed-wing airborneelectromagnetic survey system which was putted into actual production.This article rely on the major projects of National863Program “airbornegeophysical survey system” sub-topic “time-domain fixed-wing airborneelectromagnetic exploration systems research and development”,In this article,I made a research on the control part of the domestic iFTEM time-domain fixed-wing airborneelectromagnetic survey system,Researching the Bipola combination wave transmittingcircuit, the characteristics of the emission system control signal, the hardware part andsoftware part of the signal generator,how to write the driver of signal generator, how towrit the control programe using LabVIEW. These studies has academic value andpractical significance to improve the exploration ability of our resources and instrumentresearch of domestic time-domain fixed-wing AEM, and it is also conducive tonarrowing the research gap with foreign countries in this field.The major work in the paper:1.Analysis and calculate bipolar combination waveof the iFTEM transmitting circuit principle.2. Analyzing the characteristics of thecontrol signals which were used to imeplement bipolar combination wave by thelaunch system.3. Choose Altera Corporation EP1C6T144C8chip as the main chip ofthe signal generator,and use Verilog hardware description language to complete thedesign and simulation of the signal generator software debugging.4. Completing thehardware design and debug of the signal generator based on PC104bus.5.Writing anddebugging signal generator’s driver code.6.Using LabVIEW design a beautifulinterface and PC control program which is easy to operate.The final results of the paper is to design a signal generator based on PC104includes a complete hardware and software systems,The signal generator has beensuccessfully applied to domestic iFTEM type time-domain fixed-wing airborneelectromagnetic survey system.This essay is organized as follows:The first chapter introduces the researchbackground, research significance, the development and current situation of the statusquo at home and abroad as well as the signal generator of time-domain fixed-wingairborne electromagnetic survey system; The second chapter describes the iFTEMemission system components, the waveform of the system transmitted, Bipolarcombination wave transmitter circuit and the characteristics of the driving signal of thelaunch system; The third chapter describes the hardware components of the signalgenerator and system hardware circuit and made a presentation and analysis of thesystem hardware circuit; The fourth chapter details the signal generator FPGA softwaredesign and simulation, and analysis and test signal synchronization; The fifth chapterintroduces the driver development tools and design of the driver design of the signalgenerator; Chapter6describes how to use LabVIEW to design the control interface.