基于频率域三维等效源的磁梯度张量转化方法

针对传统空间域条件下等效源计算方法中存在参数设计复杂、受噪声影响较大的问题，提出基于频率域等效源的磁梯度张量正则化转化方法。给出基于频率域地下水平长方体层的磁梯度张量正演理论，为频率域的反演计算提供理论基础；构建频率域三维等效源，并利用迭代法自适应确定地下网格划分深度与精度，实现计算过程的自动化。采用C范数正则化选择方法对地下等效源模型的磁梯度张量数据进行正演计算，提高了计算结果的稳定性。仿真和试验结果表明，在噪声条件下，该方法能够准确还原磁性异常体的磁梯度张量数据，具有较好的抗噪性以及计算效率。

Magnetic Gradient Tensor Transformation Method Based on Three-dimensional Equivalent Source in Frequency Domain

A magnetic gradient tensor transformation method based on three-dimensional equivalent source in frequency domain is proposed for the complex design and great noise effect of the equivalent source calculation method under the condition of traditional space domain. Firstly,a magnetic gradient tensor forward modeling theory of the underground horizontal rectangular parallelepiped layer based on the frequency domain is proposed, which provides a theoretical basis for the inversion calculation of frequency domain. And then a three-dimensional equivalent source of frequency domain is constructed, and the iterative method is used to determine the depth and precision of the underground mesh division, which realizes the automation of the calculation process. Finally, the C-norm regularization selection method is used to perform forward calculation on the magnetic gradient tensor data of underground equivalent source model, which improves the stability of the calculated results. The simulated and experimental results show that the proposed method can accurately reflect the magnetic gradient tensor data of magnetic anomalies under noise conditions, and has good noise immunity and computational efficiency.