Magnetic Target Positioning Based on Differential Errors Compensation

This article investigates the accurate positioning problem of a magnetic target in full space. The commonly used positioning approaches rely on the classical scalar triangulation and ranging (STAR) method based on the magnetic gradient tensor (MGT). In these STAR-based approaches, the MGT is approximated by the sensor differentials, which introduces ineliminable errors into the positioning results. To improve the localization accuracy, an iterative differential errors compensation positioning (DECP) method is proposed in this article. The DECP method establishes the error compensation models for the MGT and the gradient of the tensor invariant, and iteratively updates the target's position and magnetic moment to approach the true values. The proposed method is evaluated in both simulations and real-world experiments. The simulation results show that the positioning errors of the DECP method are much smaller than those of four STAR-based benchmark methods, and it is able to improve the positioning accuracy by 42.4%-86.5% in different field experiments, which demonstrates the effectiveness and robustness of the proposed method.