SYSTEMS, METHODS AND APPARATUS FOR DETERMINING DIRECTION OF MOTION OF A RADIO FREQUENCY IDENTIFICATION (RFID) TAG
First Claim
1. A method for determining a direction of motion of a Radio Frequency Identification (RFID) tag when moving along a detection path, the method comprising:
- receiving, at an antenna tilted at a tilt angle with respect to the detection path, response signals at different times from the RFID tag;
measuring a plurality of RSSI samples of the response signals received from the RFID tag;
generating a plurality of RSSI/time data points for each of the RSSI samples, wherein each RSSI/time data point defines a measured RSSI value for a particular RSSI sample versus a time that particular RSSI sample was measured;
determining the direction of motion of the RFID tag based on the plurality of RSSI/time data points.
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Abstract
The present disclosure describes a system, methods and apparatus for determining a direction of motion of an RFID tag. An RFID reader is provided that includes an antenna that is tilted at a tilt angle with respect to a detection path. Response signals from the RFID tag are received at the antenna at different times, and an RSSI sample of each response signal is measured. Based on the RSSI samples, an RSSI/time data point is generated for each of the RSSI samples. Each RSSI/time data point defines a measured RSSI value for a particular RSSI sample versus a time that particular RSSI sample was measured. Based on the plurality of RSSI/time data points, the direction of motion of the RFID tag can be determined.
64 Citations
20 Claims
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1. A method for determining a direction of motion of a Radio Frequency Identification (RFID) tag when moving along a detection path, the method comprising:
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receiving, at an antenna tilted at a tilt angle with respect to the detection path, response signals at different times from the RFID tag; measuring a plurality of RSSI samples of the response signals received from the RFID tag; generating a plurality of RSSI/time data points for each of the RSSI samples, wherein each RSSI/time data point defines a measured RSSI value for a particular RSSI sample versus a time that particular RSSI sample was measured; determining the direction of motion of the RFID tag based on the plurality of RSSI/time data points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A Radio Frequency Identification (RFID) reader designed to determine a direction of motion of an RFID tag when moving along a detection path, the RFID reader comprising:
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an antenna tilted at a tilt angle with respect to the detection path, and being designed to receive response signals at different times from the RFID tag; a processor designed to;
measure a plurality of RSSI samples of the response signals received from the RFID tag, generate a plurality of RSSI/time data points for each of the RSSI samples, wherein each RSSI/time data point defines a measured RSSI value for a particular RSSI sample versus a time that particular RSSI sample was measured, and determine the direction of motion of the RFID tag based on the plurality of RSSI/time data points. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system, comprising:
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a Radio Frequency Identification (RFID) tag; a detection path; and a portal comprising an RFID reader designed to determine a direction of motion of the RFID tag when moving with respect to the RFID reader along the detection path, the RFID reader comprising; an antenna tilted at a tilt angle with respect to the detection path so that it points into the portal or out of the portal, and being designed to receive response signals from the RFID tag at different times; a transmitter designed to transmit interrogation signals from the antenna; a receiver designed to receive response signals from the RFID tag via the antenna; and a processor designed to;
measure a plurality of RSSI samples of the response signals received from the RFID tag, generate a plurality of RSSI/time data points for each of the RSSI samples, wherein each RSSI/time data point defines a measured RSSI value for a particular RSSI sample versus a time that particular RSSI sample was measured, and determine the direction of motion of the RFID tag based on the plurality of RSSI/time data points. - View Dependent Claims (18)
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- 19. A system according to claim 19, wherein the antenna is a directional antenna.
Specification