Magnetic Field Downward Continuation Iterative Method Based on Low-pass Filter

Abstract Magnetic field downward continuation is an important technique for expanding geomagnetic database, which can separate superimposed anomalies and enhance the resolution of local anomalies. However, adaptability fixed filter operator existing algorithm to wavenumber domain frequency component observed data not good enough, leads poor applicability algorithm, resulting in algorithm. The iteration method based on a low-pass proposed this paper. First, residual terms remainder first second vertical derivatives are constructed by using stability upward continuation; Secondly, operator, single parameter two-parameter designed, effects their filtering characteristics compared. At same time, cut-off order with parameters optimized update iterative value. Simulation experimental studies carried out under different source depths. results show that convergence performance better when dealing shallow field, accuracy improved 15%–25%. effectiveness magnetic verified measured data.