Research On Electromagnetic Exploration System Based On M Sequence

With the sustained and rapid development of the economy and society,the demand for underground mineral resources,such as coal,oil and metal,is increasing.At present,the shallow mineral resources have almost been depleted.Exploring deep mineral resources has become the trend of the times.This requires the development of the electromagnetic exploration system to high precision,high reliability and deep exploration.The traditional transient electromagnetic method is the most widely used electromagnetic exploration theory at the present stage,but its low detection depth can not meet the needs of the development of the future electromagnetic exploration system.In order to meet the needs of deep exploration,the electromagnetic exploration system based on m sequence is studied in this paper:First,in order to meet the needs of deep detection,in order to meet the needs of deep detection,the multi-channel transient electromagnetic method is selected as the basic theory of the transient electromagnetic method,and the ‘multiple receivers of a transmitter' measurement system is established.In the field of excitation source signal,by comparing the characteristics of the opposite wave and pseudo-random signal,the m sequence,which is easy to produce and have good correlation,is selected as the excitation signal,and the self-correlation of the m sequence is simulated and analyzed using the MATLAB software.Secondly,in view of the slow development of the domestic electromagnetic exploration measurement system,we designed and implemented the m sequence electromagnetic exploration system.The transmitter uses the combined control of MCU and FPGA to realize the transmission of the m sequence electromagnetic signal.The receiver uses USB-4432 acquisition card,24-bit A/D acquisition technology and double stage programmable amplification filter to denoise,and realizes high resolution acquisition of electromagnetic signal.The high precision synchronous trigger of remote transmission is realized by using GPS synchronization technology.Five channels are collected synchronously.In order to improve the resolution of the measurement system,the synchronous superposition algorithm and m sequence correlation identification technology are used to deal with the signal collected by the receiver,and the signal to noise ratio of the whole system is improved.Finally,in order to verify the performance of the system,the function of the whole machine is tested: the design and analysis of the full bridge inverter drive module,the test of the transmitting waveform,the data acquisition,the data storage and the waveform replay of the receiver.