A High-Precision Magnetic Induction Through-the-Earth Positioning Scheme

Through-the-earth positioning technology plays a vital role in mine rescue. To achieve through-the-earth positioning in the complex earth that contains geomagnetic noise, water, and rocks, we design a magnetic induction through-the-earth positioning scheme that includes positioning methods and a noise reduction method. The positioning scheme achieves three-dimensional through-the-earth positioning with high precision and long distance. Using the directional characteristics of the magnetic field vector distributed by the transmitter coil horizontally placed underground, we design two positioning methods to determine the horizontal two-dimensional position and vertical dimensional position of the transmitter, respectively. Taking advantage of the extremely narrow bandwidth of the sinusoidal signal in the spectrum, we design a noise reduction method to reduce the influence of noise on positioning accuracy. The simulation results show that the positioning error of the positioning method based on the signal direction is less than that of the positioning methods based on the equations, path loss, and the optimization algorithm, and the noise reduction performance of the frequency-point amplitude acquisition method is better than that of the bandpass filter. The simulation results also show that the positioning scheme proposed in this paper can penetrate 1000 meters of the earth to achieve high-precision through-the-earth positioning with errors of less than 2 meters.