Design of an airborne concentric frequency-domain electromagnetic induction system for shallow subsurface geophysical exploration

Abstract

For the exploration of shallow and small subsurface targets, rigid-beam helicopter-borne electromagnetic systems are often inconvenient or costly, whereas man-portable or ground-based systems are difficult to operate in complex terrain. An airborne concentric frequency-domain electromagnetic system with an unmanned rotorcraft as a flying platform is proposed to avoid the problems of low security in conventional helicopter-borne electromagnetic method and low efficiency in ground-based electromagnetic method for the exploration of shallow subsurface targets. Compared with the series mode of man-portable system, the currents of transmitting and bucking coils are assumed to be separately and continuously adjustable, which can reduce sensitivity of the small errors of the system. In this paper, the principle of canceling the primary magnetic field is analyzed. The design index of the physical parameters of the sensor is determined. The simulation experiment of layered earth model is carried out to verify the feasibility of the proposed system.

KEYWORDS:

• Airborne frequency-domain electromagnetic (FEM) method
• primary magnetic field
• shallow subsurface exploration
• layered earth model

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 42074152].

Notes on contributors

Changsheng Liu

Changsheng Liu received his B. Sc. Degree from Central South University in 2003 and Ph. D. degree from Jilin University in 2009. Now he is professor and vice President of college of instrument and electrical engineering, Jilin university. His main research interest is electromagnetic detection method and apparatus.

Zhuowei Li

Zhuowei Li is a doctoral student of Jilin University, Changchun, China. She received a bachelor's degree from Jilin University in 2018. Her main research interest is the theoretical analysis of frequency-domain airborne electromagnetic system.

Jianglan Bai

Jianglan Bai is a graduate student of Jilin University, Changchun, China. She received a bachelor’s degree from Heilongjiang Institute of Technology in 2018. Her main research interests data processing of Airborne magnetotelluric method.

Jie Liang

Jie Liang received the B.S. degree from the Guangdong University of Technology in 2015, and the M.S. degree from Henan Normal University in 2018. She is currently pursuing the Ph.D.degree in Jilin University. Her research interest including imaging methods for use in semi-airborne frequency domain electromagnetic surveys.

Shuxu Liu

Shuxu Liu is a graduate student of Jilin University, Changchun, China. He received a bachelor’s degree from Changchun University of Science and Technology in 2020. His main research interests hardware design of frequency domain electromagnetic detection system.