Electromagnetic position single axis system
AssigneeBiosense, Inc.
InventorAssaf Govari
Life of this patent
Estimating the term…
Abstract
A system for determining the position of a medical device having a sensor comprises a plurality of field radiators wherein each field radiator has a plurality of radiator elements. Each radiator element generates a magnetic field such that each magnetic field is distinct from one another due to the use of a different frequency through simultaneous energizing of the radiator elements. A signal processor is operatively connected to the field radiators and the sensor of the medical device for receiving a sensing signal from the sensor indicative of the magnetic field sensed at the sensor. Alternative field radiator arrangements are also provided in conjunction with a novel algorithm utilizing a global convergent technique.
Claims31
A system for determining the position of a medical device having a sensor, said system comprising:
- a plurality of field radiators, each field radiator having a plurality of radiator elements, each radiator element generating an electromagnetic field distinct from one another through simultaneous energizing of said radiator elements;
- a signal processor operatively connected to said field radiators and said sensor of said medical device, said signal processor receiving a sensing signal from said sensor indicative of the electromagnetic field sensed at said sensor, said sensing signal defining a measured electromagnetic field at said sensor, said signal processor also having a desired range of accuracy for said system stored therein, said signal processor including:
- (a) an initial position estimator for establishing an initial position estimate for said sensor;
- (b) a magnetic field calculator for calculating the electromagnetic field at said initial position estimate;
- (c) a steepest descent calculator for calculating a steepest descent of said calculated electromagnetic field to said measured electromagnetic field;
- and
- (d) a new position estimate calculator for calculating a new position estimate of said sensor based on said steepest descent;
- wherein said signal processor determines said position of said sensor when said new position estimate of said sensor is within said desired range of accuracy.
A system for determining the position of a medical device having a sensor, said system comprising:
- a plurality of field radiators, each field radiator having a plurality of radiator elements, each radiator element generating an electromagnetic field distinct from one another through simultaneous energizing of said radiator elements;
- a signal processor operatively connected to said field radiators and said sensor of said medical device, said signal processor receiving a sensing signal from said sensor indicative of the electromagnetic field sensed at said sensor, said sensing signal defining a measured electromagnetic field at said sensor, said signal processor also having a desired range of accuracy for said system stored therein, said signal processor including:
- (a) an initial position estimator for establishing an initial position estimate for said sensor;
- (b) a magnetic field calculator for calculating the electromagnetic field at said initial position estimate;
- (c) a global converger for determining the minimum field at said sensor based on a direction of the initial position estimate;
- and
- (d) a new position estimate calculator for calculating a new position estimate of said sensor based on said steepest descent;
- wherein said signal processor determines said position of said sensor when said new position estimate of said sensor is within said desired range of accuracy.
A method of determining the position and orientation of a sensor relative to a plurality of field radiators of known location, each of said field radiators comprising a plurality of co-located radiator elements, each radiator element generating an electromagnetic field distinct from one another through simultaneous energizing of said radiator elements, said sensor producing sensing signals indicative of a measured electromagnetic field at said sensor, said method comprising the steps of:
- (a) establishing a desired range of accuracy;
- (b) determining an initial estimate of sensor position and orientation;
- (c) calculating an electromagnetic field at the estimated sensor position and orientation;
- (d) calculating the steepest descent from the calculated electromagnetic field at the estimated sensor position and orientation to the measured electromagnetic field at the sensor;
- (e) calculating a new estimate for said sensor position and orientation from said steepest descent;
- (f) iterating steps (c)-(e) based on said newly calculated sensor position and orientation estimate of step (e) to refine the sensor position and orientation estimate.
A method of determining the position and orientation of a sensor relative to a plurality of field radiators of known location, each of said field radiators comprising a plurality of co-located radiator elements, each radiator element generating an electromagnetic field distinct from one another through simultaneous energizing of said radiator elements, said sensor producing sensing signals indicative of a measured electromagnetic field at said sensor, said method comprising the steps of:
- (a) establishing a desired range of accuracy;
- (b) determining an initial estimate of sensor position and orientation;
- (c) calculating an electromagnetic field at the estimated sensor position and orientation;
- (d) determining a minimum electromagnetic field at said sensor based on a direction of the initial position estimate using a global convergent technique;
- (e) calculating a new estimate for said sensor position and orientation based on said minimum electromagnetic field;
- (f) iterating steps (c)-(e) based on said newly calculated sensor position and orientation estimate of step (e) to refine the sensor position and orientation estimate.
Dependencies are inferred from the claim text.