A Pseudo-adaptive Hum Filter to Suppress Rotor Noise In High-resolution Airborne Magnetic Data

A unique filtering approach designed to eliminate helicopter rotor noise on aeromagnetic data without affecting the frequency content of signal provides a powerful harmonic noise suppression tool for data acquired with modern large dynamic range recording systems. This three-step approach—polynomial fitting, bandpass filtering, and rotor noise synthesis—significantly reduces the rotor noise and does not alter the spectra of signals. The approach to modeling the rotor noise is stable and efficient. Real data examples demonstrate this method can suppress rotor noise by more than 90% when implemented in an aeromagnetic data processing flow.