Can magnetic fields accurately measure positions of ferromagnetic objects?
Many creatures in nature, including butterflies, newts and mole rats, use the Earth's inherent magnetic field lines and field intensity variations to determine their geographical position. A research team at the University of Minnesota has shown that the inherent magnetic fields of ferromagnetic objects can be similarly exploited for accurate position measurements of these objects. Such position measurement is enabled in this research by showing that the spatial variation of magnetic field around an object can be modeled using just the geometry of the object under consideration. Using this model of magnetic field variation with position and measuring the magnetic field at the sensor's location, the position of the ferromagnetic object is calculated.