Patent ID: 6201987
Filing Date: 2001-03-13
Classification: G01R

Abstract:
A system for determining a position of a device within a selected tracking volume, in the presence of at least one eddy current inducing structure, the system comprising:a) at least one transmit coil at a known location capable of creating a magnetic field within the selected tracking volume;b) at least one receive coil incorporated into the device being tracked for detecting changes in the magnetic field within the selected tracking volume;c) system electronics operating to supply a current of a selected amplitude, frequency and duration to the at least one transmit coil, and capable of receiving signals detected by the at least one receive coil; andd) a current correction means capable of modifying the current supplied to the at least one transmit coil by the electronics subsystem, said current correction means modifying said current by combining an ideal current with a compensation current, said compensation current being determined so that the resulting magnetic field within the selected tracking volume is substantially free of deviations from an ideal magnetic field caused by eddy currents in the at least one eddy current inducing structure.