A method for estimating magnetic target location by employing total field and its gradients data

In this paper, we present a magnetic target localization method by measurement of total field and its spatial gradients. We deduce an approximate formula of the target's bearing vector expressed by the total field and its gradients. The total field and its gradient can be measured by a scalar magnetometer array and the approximate value of the bearing vector can be calculated. An iterative method is introduced to improve the localization accuracy of the magnetic target. Simulations experiments have been done to evaluate the performance of the proposed method. The results show that the relative errors of the bearing vector estimated by the iterative method can be kept below the level of 5%. In addition, when difference root-mean-square (RMS) noise is added to the magnetometers, the relative errors of the bearing vector only vary from 0.8 to 6%, which indicates that the proposed method has a high tolerance to the noise of the magnetometers.