Motion tracking techniques for RFID tags
First Claim
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1. A method comprising:
- receiving a sequence of readings from a radio frequency identification (RFID) tag;
determining a received signal strength indicator (RSSI) for each reading in the sequence of readings;
generating a first sequence of RSSIs based upon the RSSIs determined for the sequence of readings; and
determining motion-related information for the RFID tag based upon the first sequence of RSSIs and reference information, the motion-related information comprising information indicative of a path of motion of the RFID tag and information indicative of a direction of motion of the RFID tag along the path, the reference information comprising a plurality of RSSI vectors, each vector comprising a sequence of RSSIs and being associated with information indicative of a path of motion and a direction of motion;
wherein determining the motion-related information comprises;
determining, from the plurality of RSSI vectors, a RSSI vector having a smallest Euclidian distance to the first sequence of RSSIs; and
outputting a path of motion and a direction of motion associated with the determined RSSI vector as the path of motion and the direction of motion of the RFID tag.
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Abstract
Techniques for tracking the motion of an RFID tag using signal strength information. A single antenna of an RFID reader may be used to take a sequence of readings from an RFID tag in motion. A signal strength indicator (e.g., received signal strength indicator (RSSI)) is determined for each reading. The sequence of RSSIs is then used to estimate a path of motion of the RFID tag and the direction of motion of the RFID tag along the path.
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Citations
10 Claims
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1. A method comprising:
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receiving a sequence of readings from a radio frequency identification (RFID) tag; determining a received signal strength indicator (RSSI) for each reading in the sequence of readings; generating a first sequence of RSSIs based upon the RSSIs determined for the sequence of readings; and determining motion-related information for the RFID tag based upon the first sequence of RSSIs and reference information, the motion-related information comprising information indicative of a path of motion of the RFID tag and information indicative of a direction of motion of the RFID tag along the path, the reference information comprising a plurality of RSSI vectors, each vector comprising a sequence of RSSIs and being associated with information indicative of a path of motion and a direction of motion; wherein determining the motion-related information comprises; determining, from the plurality of RSSI vectors, a RSSI vector having a smallest Euclidian distance to the first sequence of RSSIs; and outputting a path of motion and a direction of motion associated with the determined RSSI vector as the path of motion and the direction of motion of the RFID tag. - View Dependent Claims (2, 3)
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4. A system comprising:
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a reader comprising an antenna; and a data processing system communicatively coupled with the reader; wherein the reader is configured to; take, using the antenna, a sequence of readings from an radio frequency identification (RFID) tag; and determine a received signal strength indicator (RSSI) for each reading in the sequence of readings; wherein the data processing system is configured to; generate a sequence of RSSIs based upon the RSSIs determined for the sequence of readings; and determine motion-related information for the RFID tag based upon the sequence of RSSIs and reference information, the motion-related information comprising information indicative of a path of motion of the RFID tag and information indicative of a direction of motion of the RFID tag along the path, the reference information comprising a plurality of RSSI vectors, each vector comprising a sequence of RSSIs and being associated with information indicative of a path of motion and a direction of motion; wherein to determine the motion-related information, the data processing system is further configured to; determine, from the plurality of RSSI vectors, a RSSI vector having a smallest Euclidian distance to the first sequence of RSSI; and output a path of motion and a direction of motion associated with the determined RSSI vector as the path of motion and the direction of motion of the RFID tag. - View Dependent Claims (5, 6, 7)
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8. A system comprising:
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a memory configured to store a sequence of signal strength indicators (RSSIs) corresponding to a sequence of readings taken from a radio frequency identification (RFID) tag; and a processor coupled with the memory, the processor configured to determine motion-related information for the RFID tag based upon the sequence of RSSIs, the motion-related information comprising information indicative of a path of motion of the RFID tag and information indicative of a direction of motion of the RFID tag along the path. wherein the memory is configured to store reference information comprising a plurality of RSSI vectors, each vector comprising a sequence of RSSIs and being associated with information indicative if a path of motion and a direction of motion; and the processer is configured to; determine, from the plurality of vectors, a vector with smallest Euclidian distance to the sequence of RSSIs corresponding to the sequence of reading taken from the RFID tag; and output a path of motion and a direction of motion information associated with the determined vector as the path of motion and the direction of motion of the RFID tag. - View Dependent Claims (9)
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10. A system comprising:
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a memory configured to store a sequence of signal strength indicators (RSSIs) corresponding to a sequence of readings taken from a radio frequency identification (RFID) tag; and a processor coupled with the memory, the processor configured to determine motion-related information for the RFID tag based upon the sequence of RSSIs, the motion-related information comprising information indicative of a path motion of the RFID tag and information indicative of a direction of motion of the RFID tag alone the path, wherein the memory is configured to store reference information comprising a plurality of RSSI vectors, each vector comprising a sequence of RSSIs, each vector associated with a label indicative of a path of motion and a direction of motion; and the processor is configured to; determine a set of multiple vectors from the plurality of vectors with smallest Euclidian distances to the sequence of RSSIs corresponding to the sequence of readings taken from the RFID tag; determine, from labels associated with the set of vectors, a label associated with most vectors in the set of vectors; and output a path of motion and direction of motion information indicated by the determined label as the path of motion and the direction of motion of the RFID tag.
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Specification