A Novel Magnetic Multitarget Localization Method Based on Energy Mutation Detection

Multi-target localization methods based on survey area data have significant efficiency advantages in applications such as unexploded ordnance detection. However, the existing methods still have many problems, including the target detection accuracy depends on the prior information, the parameter estimation accuracy is affected by the number of targets, the localization result is sensitive to the change of the magnetic moment direction, and the horizontal localization accuracy exhibits significant anisotropy. To solve these problems, this study proposes a novel magnetic multi-target localization method based on energy mutation detection. The method first transforms magnetic anomaly gradient vertical to the survey line into the energy domain using two-dimensional orthogonal basis functions, generating a new energy function. Then, the energy mutation detection method is used to identify target energy within local energy peaks. Finally, the target’s horizontal coordinates are determined based on the peak locations. Simulation results demonstrate the proposed method’s significant advantages over the total field two-dimensional orthogonal basis function method. At a noise standard deviation of 20 nT/m, the method reduces the root mean square errors (RMSEs) of localization results in X- and Y-directions by 88.6% and 86.0%, respectively, while decreasing anisotropy in horizontal localization accuracy by 92.8%. Moreover, the method exhibits enhanced robustness to magnetic moment direction variations. In multi-target localization experiment, all targets were successfully identified, confirming the efficacy of the energy mutation detection method. Field experimental results closely match simulation data, underscoring the method’s practical utility.