System for three dimensional positioning and tracking
First Claim
1. A system for indicating a disturbance in an electromagnetic field, the system comprising:
- a plurality of transmitters operative to transmit a corresponding plurality of alternating electromagnetic fields within a three-dimensional space; and
at least one sensor arranged to be fixed to at least one corresponding portion of a moving object whose position it is sought to monitor, each of said at least one sensors comprising;
an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of each of the plurality of alternating electromagnetic fields;
an accelerometer operative to independently measure at least one component of the acceleration of the moving object; and
a digital signal processor for storing at least one characteristic of each of the plurality of electromagnetic fields as received by the electromagnetic field receiver, and at least one characteristic of the acceleration as measured by the accelerometer, wherein said digital signal processor is adapted to transmit the at least one stored characteristic of each of the plurality of electromagnetic fields to a Kalman filter and calculate therefrom a first estimate of at least one component of the position and orientation of the moving object;
transmit the at least one stored characteristics of each of the plurality of electromagnetic fields and the at least one characteristic of the acceleration as measured by the accelerometer to the Kalman filter, and calculate therefrom a second estimate of at least one component of the position and orientation of the moving object; and
compare said first and second estimates for a discrepancy indicating a disturbance in the electromagnetic field, wherein a discrepancy indicating a disturbance in the electromagnetic field comprises a discrepancy of greater than the expected absolute accuracy of the measurement of the position and orientation of the moving object.
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Accused Products
Abstract
A system for tracking and positioning a moving object, the system including a plurality of transmitters operative to transmit alternating electromagnetic fields within a three-dimensional space and at least one sensor arranged to be fixed to at least one corresponding portion of a moving object whose position it is sought to monitor. Each of said at least one sensors includes an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of the alternating electromagnetic fields, an accelerometer to independently measure at least one component of the acceleration of the moving object; and a digital signal processor. The digital signal processor is adapted to store at least one characteristic of the electromagnetic fields as received by the electromagnetic field receiver, and at least one characteristic of the acceleration as measured by the accelerometer, and to transmit the stored characteristics to a Kalman filter, and to compute therefrom an estimate of at least one component of the position and orientation of the moving object.
128 Citations
26 Claims
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1. A system for indicating a disturbance in an electromagnetic field, the system comprising:
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a plurality of transmitters operative to transmit a corresponding plurality of alternating electromagnetic fields within a three-dimensional space; and
at least one sensor arranged to be fixed to at least one corresponding portion of a moving object whose position it is sought to monitor, each of said at least one sensors comprising;
an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of each of the plurality of alternating electromagnetic fields;
an accelerometer operative to independently measure at least one component of the acceleration of the moving object; and
a digital signal processor for storing at least one characteristic of each of the plurality of electromagnetic fields as received by the electromagnetic field receiver, and at least one characteristic of the acceleration as measured by the accelerometer, wherein said digital signal processor is adapted to transmit the at least one stored characteristic of each of the plurality of electromagnetic fields to a Kalman filter and calculate therefrom a first estimate of at least one component of the position and orientation of the moving object;
transmit the at least one stored characteristics of each of the plurality of electromagnetic fields and the at least one characteristic of the acceleration as measured by the accelerometer to the Kalman filter, and calculate therefrom a second estimate of at least one component of the position and orientation of the moving object; and
compare said first and second estimates for a discrepancy indicating a disturbance in the electromagnetic field, wherein a discrepancy indicating a disturbance in the electromagnetic field comprises a discrepancy of greater than the expected absolute accuracy of the measurement of the position and orientation of the moving object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 24, 25, 26)
a position determination unit operative, based on the signed amplitude values determined by the envelope detector module, to provide an output indication of the positions of each electromagnetic field receiver.
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26. A system according to claim 25 wherein said envelope detector module comprises a plurality of envelope detectors each including a phase locked loop, (PLL).
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12. A method for indicating a disturbance in an electromagnetic field, the method comprising:
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positioning a plurality of transmitters operative to transmit alternating electromagnetic fields within a three-dimensional space; and
affixing at least one sensor to at least one corresponding portion of a moving object whose position it is sought to monitor, each of said at least one sensor comprising;
an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of the alternating electromagnetic fields; and
an accelerometer operative to independently measure at least one component of the acceleration of the moving object;
storing at least one characteristic of the electromagnetic fields as received by the electromagnetic field receiver, and at least one characteristic of the acceleration as measured by the accelerometer, transmitting the at least one stored characteristic of the electromagnetic fields to a Kalman filter and calculating therefrom a first estimate of at least one component of the position and orientation of the moving object;
transmitting the at least one stored characteristic of the electromagnetic field and the at least one characteristic of the acceleration as measured by the accelerometer to the Kalman filter, and calculating therefrom a second estimate of at least one component of the position and orientation of the moving object; and
comparing said first and second estimates for a discrepancy indicating a disturbance in the electromagnetic field, wherein a discrepancy indicating a disturbance in the electromagnetic field comprises a discrepancy of greater than the expected absolute accuracy of the measurement of the position and orientation of the moving object. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
said electromagnetic field receiver is operative to receive at least one component, lying along the at least one active axis respectively, of each of the plurality of alternating electromagnetic fields; - and
said storing step comprising storing at least one characteristic of each of the plurality of electromagnetic fields as received by the electromagnetic field receiver.
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Specification