Adaptive Suppression Method for Aeromagnetic Interference Based on Dual Magnetic Sensors

Aeromagnetic compensation plays an important role in airborne magnetic anomaly detection. In recent years, aeromagnetic compensation has developed from the initial coarse compensation stage to the current refined compensation stage. With the deepening of the understanding of interference sources, the compensation accuracy is progressively improved. Nevertheless, further enhancement is confronted with the problems of unknown interference sources and strong coupling. Facing this problem, this paper proposes an adaptive noise suppression algorithm based on dual magnetic sensors (ANSD). First, a general compensation model (GCM) is adopted to compensate the magnetic data collected by the dual magnetic sensors installed on the aircraft to remove the magnetic interference that can be modeled and compensated. Then, a noise suppression method is developed by making use of the correlations in the recombined data which amplifies both the common components of the magnetic field data from the two sensors and the differential components of the remaining magnetic field data. Considering the time-varying nature of the magnetic noise, an adaptive noise suppression algorithm is formed by continuously solving the filtering parameters through a sliding window. Field tests demonstrate that this algorithm can effectively reduce the magnetic interference, the standard deviation of the residual magnetic interference after processing is consistently held below 8 pT in the calibration flight, and the magnetic interference compensation ability is about two to three times more than that of the traditional magnetic compensation method.