Systems and methods to determine kinematical parameters using RFID tags
First Claim
1. A method implemented in a radio frequency identification (RFID) system, the method comprising:
- identifying, by an RFID reader, an RFID tag using an interrogating electromagnetic wave generated at an antenna of the RFID reader according to an interrogating signal from the RFID reader;
receiving, in the RFID reader, a radio frequency signal from the RFID tag during interrogation of the RFID tag, wherein the received radio frequency signal is a reflection of the interrogating signal from the RFID tag, wherein the radio frequency signal is generated by the RFID tag by switching an antenna of the RFID tag between an absorptive mode and a reflective mode;
generating a profile signal of a combination of the received radio frequency signal and the interrogating signal;
determining magnitude of a portion of the profile signal corresponding to the antenna of the RFID tag being in the reflective mode; and
determining a kinematical parameter of the RFID tag relative to the RFID reader based on the magnitude of the portion of the profile signal, wherein the determining of the kinematical parameter of the RFID tag comprises;
identifying a plurality of characteristic points of the profile signal; and
determining a time period of the plurality of characteristic points to compute a speed of the RFID tag.
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Accused Products
Abstract
Systems and methods to determine kinematical parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, one of a population of RFID tags is selectively instructed by an RFID reader to backscatter the interrogating electromagnetic wave and thus allow the RFID reader to measure the position, speed, acceleration, jerk of the object to which the tag is attached. The RFID reader combines the signal representing the backscattered interrogating electromagnetic wave and the signal representing the interrogating electromagnetic wave transmitted by the RFID reader to determine or monitor one or more of the kinematical parameters of the object.
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Citations
30 Claims
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1. A method implemented in a radio frequency identification (RFID) system, the method comprising:
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identifying, by an RFID reader, an RFID tag using an interrogating electromagnetic wave generated at an antenna of the RFID reader according to an interrogating signal from the RFID reader; receiving, in the RFID reader, a radio frequency signal from the RFID tag during interrogation of the RFID tag, wherein the received radio frequency signal is a reflection of the interrogating signal from the RFID tag, wherein the radio frequency signal is generated by the RFID tag by switching an antenna of the RFID tag between an absorptive mode and a reflective mode; generating a profile signal of a combination of the received radio frequency signal and the interrogating signal; determining magnitude of a portion of the profile signal corresponding to the antenna of the RFID tag being in the reflective mode; and determining a kinematical parameter of the RFID tag relative to the RFID reader based on the magnitude of the portion of the profile signal, wherein the determining of the kinematical parameter of the RFID tag comprises; identifying a plurality of characteristic points of the profile signal; and determining a time period of the plurality of characteristic points to compute a speed of the RFID tag. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method implemented in a radio frequency identification (RFID) system, the method comprising:
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identifying, by an RFID reader, an RFID device using an interrogating electromagnetic wave generated at an antenna according to an interrogating signal from the RFID reader; receiving, in the RFID reader, a radio frequency signal from the RFID device during interrogation of the RFID device; generating a profile signal of a combination of the received radio frequency signal and the interrogating signal; and determining a position of the RFID device relative to the RFID reader based on the profile signal and a wavelength of the interrogating electromagnetic wave corrected according to a relative speed between the RFID device and the RFID reader. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method implemented in a radio frequency identification (RFID) system, the method comprising:
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identifying, by an RFID reader, an RFID tag using an interrogating electromagnetic wave generated at an antenna according to an interrogating signal from the RFID reader; receiving, in the RFID reader;
a radio frequency signal from the RFID tag during interrogation of the RFID tag;generating a profile signal of a combination of the received radio frequency signal and the interrogating signal; and determining a kinematical parameter of the RFID tag relative to the RFID reader based on the profile signal, including identifying a plurality of characteristic points of the profile signal; and determining a time period of the plurality of characteristic points to compute a speed of the RFID tag; wherein the determining of the time period comprises; sampling the profile signal at a predetermined time interval; counting characteristic points during one or more time periods of the predetermined time interval using the sampled profile signal; determining a time period outside the plurality of characteristic points; and eliminating the time period that is outside the plurality of characteristic points from the one or more time periods of the predetermine time interval to obtain the time period of the plurality of characteristic points. - View Dependent Claims (19)
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20. A radio frequency identification (RFID) system, comprising:
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an RFID tag; and an RFID reader within a radio communication range from the RFID tag, the RFID reader configured to identify the RFID tag using an interrogating electromagnetic wave generated according to an interrogating signal having a predetermined frequency and to receive a radio frequency signal from the RFID tag during interrogation of the RFID tag, the RFID reader to sample, at a predetermined time interval, a profile signal of a combination of the received radio frequency signal and the interrogating signal having the predetermined frequency to generate a sampled profile signal, the RFID reader further configured to use the sampled profile signal to identify a plurality of characteristic points of the profile signal and determine a time period of the plurality of characteristic points to compute a speed of the RFID tag. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A radio frequency identification (RFID) system, comprising:
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an RFID device; and an RFID reader within a radio communication range from the RFID device, the RFID reader configured to identify the RFID device using an interrogating electromagnetic wave generated according to an interrogating signal and to receive a radio frequency signal from the RFID device, the RFID reader further configured to determine a kinematical parameter of the RFID device relative to the RFID reader using a combination of the received radio frequency signal and the interrogating signal;
wherein the RFID reader comprises;a digitizer to digitize the received radio frequency signal, a digitizer to digitize the interrogating signal, and a logic unit to compute exclusive OR between the digitized received radio frequency signal and the digitized interrogating signal to generate the combination.
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27. A radio frequency identification (RFID) reader, comprising:
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an oscillator to generate an interrogating signal; at least one antenna coupled to the oscillator to generate an interrogating electromagnetic wave according to the interrogating signal; at least one receiver coupled to the at least one antenna to generate at least one received signal according to the interrogating electromagnetic wave backscattered from an RFID tag, wherein the interrogating electromagnetic wave to be backscattered is generated according to the interrogating signal having a predetermined frequency; and a processor coupled to the oscillator and the at least one receiver to identify the RFID tag and to determine a position of the RFID tag based at least in part on a profile signal of one combination of the interrogating signal having the predetermined frequency and the at least one received signals; wherein the processor is configured to determine the position based on; identifying a plurality of characteristic points of the profile signal; and determining a time period of the plurality of characteristic points to compute a speed of the RFID tag. - View Dependent Claims (28, 29)
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30. A machine readable medium storing instructions configured to instruct a radio frequency identification (RFID) system to:
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select an RFID tag from a plurality of RFID tags using an interrogating electromagnetic wave generated according to an interrogating signal from an RFID reader; receive a radio frequency signal generated according to the interrogating electromagnetic wave backscattered from the selected RFID tag, wherein the interrogating electromagnetic wave is generated according to the interrogating signal having a predetermined frequency; generate a profile signal of the received radio frequency signal mixed or summed with the interrogating signal having the predetermined frequency; and determine a kinematical parameter of the RFID tag relative to the RFID reader based on identifying a plurality of characteristic points of the profile signal and determining a time period of the plurality of characteristic points to compute a speed of the RFID tag.
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Specification