Research On Metal Prospecting VLF Method Based On Software Radio

The VLF method is of very low frequency electromagnetic method of symbol shorthand,reading and writing for VLF method.VLF method plays a very important role in the investigation and orientation of underground metal mineral deposits.However,the demand of modern society and the degree of exploration and development are gradually increasing,and the amount of the exposed ore and the shallow ore is slowly declining,resulting in the difficulty of exploration increase accordingly.This has forced us to make more accurate survey and positioning of concealed metal ore bodies,therefore,it is urgent to put forward a new geophysical prospecting plan which is combined with the application of the VLF method and software radio technology.VLF signal in the communication process in low attenuation,phase stability and VLF method,sensitivity high,low cost,no need to construct their own field emission source,so very low frequency electromagnetic method without like general electric survey that need to build power,wire and other equipment,so it is widely used in search for mineral resources,groundwater,tectonic belt,navigation etc.With the development of science and the need of the construction of our country,the demand for metal minerals has been increased.Therefore,the research and prediction of the spatial structure of the metal deposits have become the focus of the modern society.This thesis focuses on the research of the prospecting method based on the very low frequency method of the software radio.The method is based on the design of the receiver based on the software radio technology.Design is divided into three parts,the overall design scheme,hardware design and software design.The receiver uses the Russian VLF navigation system Alpha emission of high power and high precision VLF signal as field source,due to differences in the resistivity and magnetic susceptibility of the ore deposit and surrounding rock,the electromagnetic wave signal of these powerful,encountered metal mineral conductor will produce electric and magnetic induction with two times the electromagnetic wave field the signal amplitude and phase of alienation,Through the antenna,anti aliasing filter,A/D converter and other hardware devices for selectively receiving,and finally by the digital signal processor is analyzed and calculated the change of induced electromagnetic field amplitude and phase volume,electromagnetic field vertical component,horizontal component and polarization angle and determine the precise location of zero crossings,comprehensive geological reasoning plus accurate,lay the foundation for the low resistance abnormal body.Therefore,the VLF method based on software radio is desirable,simple,economical and reliable.