A high-precision long-distance magnetic induction through-the-earth positioning method

To achieve through-the-earth positioning for mine rescue, A high-precision long-distance magnetic induction through-the-earth positioning method was proposed. A loop energized coil placed horizontally underground was used as the positioning signal transmitter, and two three-axis orthogonal magnetic core coils at different positions on the ground were used as the receivers. Using the characteristic that the horizontal components of the positioning signals point to the axis of the loop coil of the transmitter, a triangle including the receivers and the positioning signal vectors was constructed. The horizontal two-dimensional azimuth of the transmitter was calculated by using the sine theorem. When determining the depth of the transmitter, mathematical tools such as vector decomposition and coordinate transformation were first used to split the positioning signal vector. Then, the law that the intensity of each component of the positioning signal varies with the transmission distance was discussed. After the one-to-one corresponding relationship between the positioning signal strength and the transmitter depth was established, the transmitter depth by using the iterative calculation was determined. The simulation results show that using the positioning methods, the through-the-earth positioning method can achieve extremely high-precision through-the-earth positioning at depth of 1 000 m. © 2021, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.