System and method for measuring position and orientation using distortion-compensated magnetic fields
AssigneeAscension Technology Corporation
InventorMark R. Schneider
Life of this patent
Estimating the term…
Abstract
An electromagnetic tracking system (600) and a distortion compensation method (500) that utilize a lead-lag network model to compensate for position and orientation distortion caused by eddy currents formed in one or more conductive distorters (330, 658A-C) located within a tracking environment during electromagnetic tracking of one or more objects (612). the method is adaptive relative to the amount of distortion cause by the conductive distorters.
Claims19
A method of locating an object, comprising the steps of:
- a) generating at least one magnetic field;
- b) sensing said at least one magnetic field so as to generate at least one frequency response;
- c) representing said at least one frequency response in terms of at least one lead-lag network;
- and
- d) determining at least one of position and orientation of the object as a function of said at least one lead-lag network;
- wherein step c) comprises representing said at least one frequency response as a transfer function, Hsensor(s), that is a function of parameters k, pj and zj, said transfer function being:
- H
- sensor
-
- (
- s
- )
- =
- k
-
- ∑
- j
-
- s
- +
- z
- j
- s
- +
- p
- j
- .
A method of locating an object, comprising the steps of:
- a) receiving at least one frequency response of at least one magnetic field sensor;
- b) representing said at least one frequency response in terms of at least one lead-lag network;
- and
- c) determining at least one of position and orientation of the object as a function of said at least one lead-lag network;
- wherein step b) comprises representing said at least one frequency response as a transfer function, Hsensor(s), that is a function of parameters k, pj and zj, said transfer function being:
- H
- sensor
-
- (
- s
- )
- =
- k
-
- ∑
- j
-
- s
- +
- z
- j
- s
- +
- p
- j
- .
A computer readable medium containing computer instructions for determining the location of an object, said computer instructions comprising:
- a) a first set of instructions for receiving at least one frequency response of at least one magnetic field sensor;
- b) a second set of instructions for representing said at least one frequency response in terms of at least one lead-lag network;
- and
- c) a third set of instructions for determining at least one of position and orientation of the object as a function of said at least one lead-lag network;
- wherein said second set of instructions comprises instructions for representing said at least one frequency response as a transfer function, Hsensor(s), that is a function of parameters k, pj and zj, said transfer function being:
- H
- sensor
-
- (
- s
- )
- =
- k
-
- ∑
- j
-
- s
- +
- z
- j
- s
- +
- p
- j
- .
A system for determining the location of an object, comprising:
- a) at least one magnetic field sensor;
- and
- b) a processor having an input operatively configured to receive at least one frequency response of said at least one magnetic field sensor, said processor operatively configured to:
- i) represent said at least one frequency response in terms of at least one lead-lag network;
- and
- ii) determine at least one of position and orientation of the object as a function of said at least one lead-lag network
- wherein said processor is operatively configured to represent said at least one frequency response as a transfer function, Hsensor(s), that is a function of parameters k, pj and zj, said transfer function being:
- H
- sensor
-
- (
- s
- )
- =
- k
-
- ∑
- j
-
- s
- +
- z
- j
- s
- +
- p
- j
- .
Dependencies are inferred from the claim text.