Patent ID: 6400139
Filing Date: 2002-06-04
Classification: A61B,G01S,G06F

Abstract:
Apparatus for determining the position and orientation of an object within a bounded volume of interest in the presence of electromagnetic distortion, the apparatus comprising:a real source of an electromagnetic field having measurable magnetic induction-vector components; one or more stationary witness sensors supported near or within the volume of interest, each witness sensor being operative to measure the induction-vector components using a fixed known position and orientation; one or more probe sensors supported on the object for measuring the induction-vector components; and a processor in communication with each witness sensor and each probe sensor, the processor being operative to perform the following functions: a) compute the characteristics of at least one effective electromagnetic source, the effective source being defined as a model source which would produce the field in the vicinity of each witness sensor similar, or identical, to the field generated by the real source, along with electromagnetic distortion present in the volume, b) receive the induction-vector components measured by each probe sensor, and c) compute the position and orientation of the object by applying the spatial and electromagnetic magnetic characteristics of the effective source to the induction-vector components measured by each probe sensor.