Improvement Of Capacitance Sensor Based On AEMT

In recent years,the demand of geophysics is not only limited to shallow and qualitative exploration,but also requires deep and quantitative results,which requires the development of geophysical methods and instruments.For example,based on magnetotelluric method,AMT,CSAMT and so on are derived.In recent years,some scholars have proposed the Air Electric Field Magneto-Telluric method.Compared with other magnetotelluric methods,AEMT uses capacitance instead of grounding electrode,This method can improve work efficiency and solve the problem of low efficiency of traditional contact measurement method when people are facing complex geological environment;according to the effect of previous generations of capacitive sensors,the stability and capacitance value need to be improved.The improvement of capacitance sensor in AEMT method and the corresponding research are the main research contents of this paper.Firstly,this paper introduces the basic principle of AEMT method.On this basis,according to the shortcomings of previous generations of capacitive sensors,a new generation of capacitive sensor is made,which improves the capacity and stability of the sensor,and uses the new sensor to measure Aether instrument.Before the formal data acquisition,the acquisition time,filter parameters and electrode selection test of Aether instrument are carried out,and the sampling rate range is determined according to the sampling theorem,and the appropriate acquisition parameters are obtained.In the same section,the AMT and AEMT methods are used respectively.The AMT method uses metal electrode and unpolarized electrode for comparative test.After the data is collected,the preprocessing is carried out with the processing software pr MT of ether,including FFT windowing and robust impedance estimation,and good noise reduction effect is obtained.FFT windowing can reduce the problem of frequency leakage,Robust estimation can be used to eliminate "flying point" data in areas with large interference while maintaining authenticity.After that,the obtained data are inverted,and three inversion results are obtained,and these results are compared and analyzed.Finally,according to the test of the interference characteristics of the capacitive sensor,it is concluded that the interference degree of the capacitive sensor is inversely proportional to the frequency,and the greater the interference is,the more serious the interference is to the low frequency.