A method for positioning multiple weak magnetic target signals under the interference of strong magnetic sources

When locating multiple magnetic targets, the interference between each magnetic dipole is often ignored, we propose a method to detect and locate multiple weak magnetic target signals under the interference of strong magnetic sources. First, under different burial depths, the influence of shallow magnetic sources and deep magnetic sources on each other was studied and the conclusion was drawn that shallow targets are less affected by deep targets, while deep targets have the opposite effect; and the normalized source strength (NSS) is introduced into the concept of magnetic inclination in the terrain field, this simultaneously utilizes the insensitivity of magnetic inclination to burial depth and the isotropy of NSS to amplify the signal characteristics of submerged deep targets, and initially obtains the horizontal position of the measured target; the idea of locating shallow targets first, removing the interference of shallow targets, and then locating deep targets is proposed, The results of positioning were fitted and optimized by moth Moth-Flame Optimization (MFO), and the accuracy of positioning was improved. In the simulation, compared with the total magnetic field intensity (TMI), the root mean square error (RMSE) of the positioning results of the three measured targets after using the proposed method is reduced from 0.2820, 0.1831 and 0.3972 to 0.0112, 0.0145 and 0.0326, the positioning error of deep target is greatly reduced, which proves the feasibility of the proposed method, in the actual experiment, the positioning accuracy of the deep measured magnetic source is also improved.