Accurate and Efficient Localization With a Uniaxial Rotating Permanent Magnet

Existing magnetic localization methods are often fall short to achieve the high accuracy and robustness. Therefore, we propose an accurate and efficient 6-DoF localization method using a uniaxial rotating permanent magnet (URPM). In the proposed method, a stepper motor and a permanent magnet are applied to produce the magnetic field containing the extremely low-frequency (ELF) magnetic waves. Subsequently, the magnetic field and the pole orientation of permanent magnet are detected by a magnetic sensor and an encoder to collect the meta data of localization information. After that, the tracking algorithm is proposed to convert the meta data to the 3-D position and orientation. The innovations of this method mainly contain three components: first, as the ELF magnetic waves are employed, the generated magnetic field with a wide range is able to be measured by the sensors under simplified hardware settings. Second, we apply the magnetic dipole model, combined with the geometric constraints derived from our uniaxial rotating structure design, to construct the analytic localization module of tracking algorithm to calculate the real-time 6-DoF localization. Third, the cross-loss function is introduced into the localization refinement module of tracking algorithm to improve the method’s accuracy and reliability. Extensive experiments have been conducted to evaluate the proposed method. The results demonstrates its high localization accuracy over a large operation range, and robustness to magnetic interferences. Therefore, our approach outperforms the conventional methods and has a good potential for various tracking applications.