Robust Electromagnetic Pose Estimation ...

A wire-less electromagnetic field-based sensor system is proposed which enables tracking of moving objects e.g. drones. The gathered up to 6-degrees of freedom information is complementary to existing sensing principles e.g. GPS or vision-based systems. Additionally, it can be used for stand-alone navigation or non-invasive localization of medical devices inside the human body. The sensor system is comprised of an exciter and a sensor. The exciter can be mounted on a moving robot and generates an electromagnetic field. The field is measured by the sensor and subsequently, the pose of the exciter with respect to the sensors’ pose is estimated. Conductive objects in the vicinity of the sensor alter the measured magnetic field due to induced eddy currents. In general, unmanned aerial vehicles or wheeled robots mainly consist of conductive materials, which causes a significant estimation error. This paper introduces an interference aware electromagnetic near-field based pose estimation approach. Specifically, the change of magnetic field due to close conductive and ferro-magnetic objects is modelled. Iterative numerical solutions of Maxwell’s equations, based on e.g. Finite Element Method, are avoided. Instead, an analytic expression of the change of magnetic field due to present eddy currents is given. The advantages of the proposed concept for model based low-complexity pose estimation concepts is shown using an Extended Kalman Filter. It is observed, that the tracking performance using the introduced model outperforms the traditional model in eddy current scenarios significantly.