Reference pad for position sensing

摘要

A method for position tracking includes attaching a location pad to a body of a subject and introducing into the body of the subject a first position transducer. A procedure is performed on the body of the subject using a medical tool, to which a second position transducer is fixed. Magnetic fields are transmitted between the location pad and first and second position transducers. Responsively to the magnetic fields, first and second position signals are generated. The signals are indicative of coordinates of the first and second position transducers relative to the location pad. The first and second position signals are processed so as to determine a disposition of the tool relative to the first position transducer.