None-Asphericity-Error Method for Magnetic Dipole Target Detection

There is always a relative motion between the magnetometer and the magnetic target. Especially when both are moving, in certain scenarios, the magnetometer is demanded to have the capability of point-by-point and real-time positioning. In this letter, we deduce normalized gradient formulas based on the total field gradient (TFG) and the tensor module gradient (TMG) of the target, respectively. In addition, we analyze the capability of these two formulas to determine the direction of the target. Afterward, the none-asphericity-error method based on the union of aforementioned formulas (TFG-TMG) is proposed. Simulation results show that the union method has no asphericity error on magnetic target localization as well as evaluating the magnetic moment of' the target. Even in some noisy environment, the direction error is smaller than 1 degrees and the mean error of the magnetic moment is smaller than 5% of the magnetic moment of the target.