Correction of misalignment errors in the magnetic gradient tensor measurement system and its application in localization

Abstract

The magnetic gradient tensor measurement system (MGTMS) is critical for detecting and localizing ferromagnetic targets. However, its localization accuracy is closely linked to measurement precision, which is often compromised by sensor misalignment errors. To mitigate these errors, this study proposes a practical calibration method using a standard magnetic source, achieving effective misalignment correction with minimal system alteration. The proposed method is validated through both simulations and localization experiments. Simulation results indicate that the root mean square error (RMSE) of the calibrated tensor values is reduced by three orders of magnitude compared to the uncalibrated state. Experimental results further demonstrate that the average localization error decreases from 0.040 m to 0.019 m after calibration, corresponding to a 52.5% improvement in positioning accuracy. These results highlight the potential of improving the accuracy of MGTMS-based target localization in practical applications.