Design Of Electromagnetic Integrative Receiver For Full Gradient Measurement

Electromagnetic method is an important geophysical means to detect the earth,but it is insufficient in terms of resolution and anti-jamming ability.Based on the magnetic method and gravity method,Jilin University has put forward a new method which named Frequency domain full electromagnetic gradient method to settle the matter,and we designed a new Receiver for frequency-domain full electromagnetic gradient.The paper studied the basic theory of full electromagnetic gradient and the data processing method.The main study is:1)The paper put forward the Frequency domain full electromagnetic gradient method and introduced the theory of transverse and longitudinal gradient.We used the Comsol software to simulate the gradient signals.The results show that full electromagnetic gradient method has advantages on Interference suppression and resolving power.Besides,the theory provides the basis of the design of acquisition system.2)Based on the theory of full electromagnetic gradient,the paper designed the new acquisition circuits of transverse and longitudinal gradient.The circuits consist of the low noise analog amplifier,filter,supply circuits and A/D data acquisition circuit.We designed a calibration circuit to measure the factor of data channels and to complete data correction.3)The system control software was designed.The paper studied the use of horizontal gradient field and vertical gradient data of apparent resistivity method and used matlab to complete resistivity compute.4)The paper tested the technical indicators of acquisition system,and used the system to complete practical application in Jiangsu and Jilin province.The comparison results with V8 system and JLEM air-ground system proved the validity of full electromagnetic gradient system.