Parameter Estimates of Magnetic Dipole Source Using Extended Two-Dimensional Orthonormal Basis Functions

Abstract

We have proposed an alternative method for calculating the six parameters (three position parameters and three magnetic moment parameters) of a magnetic dipole source using extended two-dimensional orthonormal basis functions (2D-OBFs). In this method, a 2D-OBF decomposition is performed on the total-field anomaly generated by the magnetic dipole to obtain parameters defined as energy. The horizontal position estimate of the dipole is determined by identifying the peak of the energy distribution. By using peaks corresponding to two different initial vertical distance estimates (the distance from the dipole to the observation plane), the final vertical distance estimate can be analytically calculated. The magnetic moment vector is then obtained by solving the corresponding analytical equation. Thus, all six magnetic dipole parameters can be calculated simultaneously. We comprehensively demonstrated the characteristics and effectiveness of the proposed method through testing with synthetic and field data. Additionally, we conducted a comparative analysis to evaluate the similarities and differences between the proposed method and the Euler deconvolution method in field data testing. Although the 2D-OBF method requires further practical application testing, we are confident in its potential for detecting magnetic dipole sources, particularly in providing reliable initial parameter estimates for iterative optimization inversion.