Research And Application Of A New Type Of Geomagnetic Signal Acquisition System

With the development of modern society,people's demand for water resources is increasing day by day.Both in terms of water quality and quantity,it is difficult to meet the development needs of our country.The reduction of high-quality surface water sources has become an inevitable trend,which has a certain impact on people's production and life.Under this condition,the detection and exploitation of groundwater sources are extremely important.At the same time,the detection of groundwater sources is also of great significance to engineering construction and other aspects,which can avoid potential safety hazards and ensure construction efficiency.Therefore,in this thesis,in view of these situations,combined with magnetotelluric water exploration technology,a set of geomagnetic signal acquisition system for groundwater resources detection is developed to ensure that the geomagnetic signal can be collected and processed accurately and effectively.The main content of this paper is as follows.Firstly,the principle of water exploration based on magnetotelluric method is studied.Magnetotelluric method is a kind of geomagnetic physical survey method based on the natural alternating electromagnetic field,which aims to study the electrical structure of the earth.It plays an increasingly significant role in engineering safety and water resources detection.Secondly,a new water detector based on Raspberry Pi 3B+ is studied.Carried out the hardware selection design and system function realization.The water detector collects two-way geomagnetic signals through traditional electromagnetic induction sensors and magnetoresistive sensors,and passes a series of processing such as passive filtering,amplification,and analog-to-digital conversion,finally stored in the Raspberry Pi 3B+ for water exploration data processing.Thirdly,digital signal processing is carried out on the collected multi-point geomagnetic signals,including the design and simulation test of digital low-pass filters and notch filters,FFT transformation and spectrum analysis,correlation analysis and power spectrum of the two signals Analyze.Then extract data from the frequency spectrum or power spectrum of each collection location at a certain frequency interval to form a color matrix geological structure map,which is used to judge the geological structure of the measured area.Through analysis,the basic situation of groundwater in the area can be obtained,which can provide a basis for the positioning of drilling wells.Finally,the instrument is used to conduct water exploration experiments in three areas,and the corresponding data are analyzed to obtain the corresponding color matrix geological structure map.Then,according to the opinions of experts,the location of drilling wells is determined.The experimental results show that the method studied in this thesis basically meets the demand of water output on the demand side.