US 7,321,228 B2
Detection of metal disturbance in a magnetic tracking system
Assaf Govari, Haifa (Israel)
Assigned to Biosense Webster, Inc., Diamond Bar, Calif. (US)
Filed on Jul. 31, 2003, as Appl. No. 10/632,217.
Prior Publication US 2005/0024043 A1, Feb. 03, 2005
Int. Cl. G01B 7/30 (2006.01); G01C 17/38 (2006.01)
U.S. Cl. 324—207.17  [324/207.12; 702/95; 702/150] 22 Claims
OG exemplary drawing
 
1. A method for tracking an object, comprising:
(i) producing energy fields at a plurality of different frequencies in a vicinity of the object;
(ii) receiving signals that are generated at a location of the object at the different frequencies in response to the energy fields;
(iii) making multiple computations of spatial coordinates of the object based on the signals received at the different frequencies; ascertaining whether the energy fields have been perturbed by an article in the vicinity of the object by testing a convergence of the computations; and
(iv) if testing reveals a convergence of the computations then repeating steps (i) through (iv) for N repetitions, wherein N equals a plurality of times.