关键词: 磁性目标, 强剩磁, 磁化方向, 磁总场模量, 奇异值分解, 无偏风险估计

Abstract: A three-dimensional focusing inversion approach of magnetic target is proposed for the effect of remanent magnetization on the true magnetization direction in the process of inversion. For an isolate magnetic source, its magnetization direction is estimated, and then the estimated magnetization direction is incorporated into an inversion algorithm. For multi-magnetic sources, the direct inversion of the total modulus data is made. Total modulus data depends weakly upon magnetization direction. In the iterative process, the depth weighting matrix and minimal support matrix are added in the inversion model of Tikhonov regularization theoretical framework to obtain the objective function and avoid the multiple solutions of inversion problem. Objective function is calculated by singular value decomposition, and the unbiased predictive risk estimator principle is used to adaptively determine the regularization parameter in the iterative process, thereby realizing the iterative process automation. Simulated and experimental results show that the proposed inversion method can reflect the outline form of magnetic anomaly and has good model resolution in the presence of significant remanence. Key

Key words: magnetictarget, significantremanence, magnetizationdirection, totalmodulusdata, singularvaluedecomposition, unbiasedpredictiveriskestimator