A Real-time Electromagnetic Localization System

This paper presents a fixed location pose estimation system based on electromagnetic fields. The sensor system is comprised of an electromagnetic field exciter mounted on a moveable platform and a stationary magnetic field sensor. The sensed data is used to estimate the relative pose of the exciter, and consequently, the pose of the moving platform. The proposed systems' accuracy increases with decreasing distance and can consequently be helpful for landing scenarios or to be fused with existing approaches showing opposing characteristics. Conductive objects in the vicinity of the sensor system, potentially the target platform itself, cause a change of magnetic field due to induced eddy currents. The introduced concept analytically models known conductive and ferromagnetic structures while maintaining realtime capabilities as required in many tracking applications. The system concept consists of analog front-ends, an analog signal conditioning stage, sampling followed by digital signal processing, and an Extended Kalman Filter that continuously updates the pose estimate. The performance of the developed concept is verified using an experimental demonstrator. It is shown that electromagnetic field-based pose estimation can act as a close-range pose measurement system while providing real-time functionality.