An aeromagnetic compensation coefficient-estimating method robust to geomagnetic gradient

Most existing methods used in aeromagnetic compensation assume a constant geomagnetic field. These methods do not take into consideration the geomagnetic gradient, which can reduce the accuracy of the estimated coefficients of the Tolles-Lawson model. In practice, aside from the magnetic interference from the aircraft, a residual component of the geomagnetic field is contained in the filtered magnetic field signal. In this letter, the component of the geomagnetic field in the filtered magnetic field signal is modeled as a function of the longitude, latitude, and altitude of the aircraft. The linear equation for estimating the coefficients is then extended by combining the Tolles-Lawson model with the proposed model. Simulation results indicate that the proposed method is able to include the variance caused by the geomagnetic gradient into the Tolles-Lawson model calculation and results in a better aeromagnetic compensation.