Method and apparatus for localization of RFID tags
First Claim
1. A method for a tag to facilitate the determination of its location, comprising:
- transmitting at a predetermined time interval from the tag an identifier associated with the tag;
determining if tag has been moved to a different position using one or more sensors associated with the tag; and
expending energy from the tag responsive to the movement determination as the tag participates in an operation that locates the tag in the different position.
1 Assignment
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Accused Products
Abstract
A method and apparatus for an RFID tag to facilitate the determination of its location while at the same time minimizing the energy drain on the tag'"'"'s battery. At predetermined intervals, the tag transmits its identifier along with status information. If the status indicates that the tag is in a new location, the tag will then expend additional battery energy by participating in the determination of its location. The distance from an interrogator to the tag is determined by transmitting two signals from the interrogator that propagate at different velocities. By determining the difference in arrival times at the tag of the two signals, the distance from the interrogator to the tag can be determined.
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Citations
20 Claims
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1. A method for a tag to facilitate the determination of its location, comprising:
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transmitting at a predetermined time interval from the tag an identifier associated with the tag;
determining if tag has been moved to a different position using one or more sensors associated with the tag; and
expending energy from the tag responsive to the movement determination as the tag participates in an operation that locates the tag in the different position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for an interrogator to determine a tag location, comprising:
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receiving at a predetermined time interval from the tag an identifier associated with the tag;
receiving an indication that the tag has changed position; and
performing a location operation in response to the indication that the tag has changed position. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A computer program product for use by a tag to facilitate the determination of its location, tangibly stored on a computer readable medium, comprising instructions operable to cause a programmable processor to:
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transmit at a predetermined time interval from the tag an identifier associated with the tag;
determine if tag has been moved to a different position using one or more sensors associated with the tag; and
expend energy from the tag responsive to the movement determination as the tag participates in an operation that locates the tag in the different position.
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19. A computer program product for use by an interrogator to determine a tag location, tangibly stored on a computer readable medium, comprising instructions operable to cause a programmable processor to
receive at a predetermined time interval from the tag an identifier associated with the tag; -
receive an indication that the tag has changed position; and
perform a location operation in response to the indication that the tag has changed position.
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20. A tag capable of assisting in the determination of its location, comprising:
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a first transmitter capable of sending an identifier associated with the tag at a predetermined time interval from the tag;
a motion sensor and timer capable of determining if tag has been moved to a different position within a predetermined interval measured by the timer; and
a second transmitter that receives signals traveling at a second velocity compared with a first velocity of signals received by the first transmitter that determines a location of the tag in a new position responsive to the motion sensor.
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Specification