Abstract: Based on a portable transient electromagnetic system, we use a dipole model with a differential evolutionary algorithm to investigate the effects of target size, depth and inclination angle on the accuracy of its characterization, using the electromagnetic characteristics of a calibrated unexploded bomb as a reference. The experimental results show that for a target with an inclination angle of 0毅, the characteristic response is more concentrated in the head of the target and the result is smaller than the calibration value, when for an inclination angle of 90°, the characteristic response is the sum of the characteristic responses of all parts of the target, so the characteristic response increases with the increase of the inclination angle. The larger the depth, the higher the applicability of the dipole model, and the closer the characteristic response is to the calibration value. The larger the depth, the higher the applicability of the dipole model, the closer the characteristic response to the calibration value, and the better the consistency of the inversion results under different inclination angles. The larger the size of the target, the more the target is affected by the change of inclination angle, the better the consistency of the characteristic response from all angles of the small-size target, and the better it matches the calibration results. In summary, factors such as size, depth and inclination angle lead to errors in the results of the feature response, but in general do not affect the classification of targets based on the dipole model. 

Key words:  ')">

 , unexploded ordnance, transient electromagnetic, differential evolution algorithm, dipole model, characterization