US20080117025A1 - RFID System and Method for Wirelessly Interfacing With an Interrogator - Google Patents

RFID System and Method for Wirelessly Interfacing With an Interrogator Download PDF

Info

Publication number
US20080117025A1
US20080117025A1 US12/016,900 US1690008A US2008117025A1 US 20080117025 A1 US20080117025 A1 US 20080117025A1 US 1690008 A US1690008 A US 1690008A US 2008117025 A1 US2008117025 A1 US 2008117025A1
Authority
US
United States
Prior art keywords
interrogator
transceiver
tag
rfid
reliable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/016,900
Inventor
John Tuttle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Round Rock Research LLC
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/990,915 external-priority patent/US5500650A/en
Priority claimed from US10/938,917 external-priority patent/US20050040961A1/en
Application filed by Individual filed Critical Individual
Priority to US12/016,900 priority Critical patent/US20080117025A1/en
Publication of US20080117025A1 publication Critical patent/US20080117025A1/en
Assigned to ROUND ROCK RESEARCH, LLC reassignment ROUND ROCK RESEARCH, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MICRON TECHNOLOGY, INC.
Assigned to MICRON TECHNOLOGY, INC. reassignment MICRON TECHNOLOGY, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KEYSTONE TECHNOLOGY SOLUTIONS, LLC
Priority to US13/460,694 priority patent/US20120274450A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W28/00Network traffic management; Network resource management
    • H04W28/16Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H04W28/18Negotiating wireless communication parameters
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/0008General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10019Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.
    • G06K7/10079Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02Alarms for ensuring the safety of persons
    • G08B21/0202Child monitoring systems using a transmitter-receiver system carried by the parent and the child
    • G08B21/023Power management, e.g. system sleep and wake up provisions
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02Alarms for ensuring the safety of persons
    • G08B21/0202Child monitoring systems using a transmitter-receiver system carried by the parent and the child
    • G08B21/0241Data exchange details, e.g. data protocol
    • G08B21/0258System arrangements wherein both parent and child units can emit and receive
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02Alarms for ensuring the safety of persons
    • G08B21/0202Child monitoring systems using a transmitter-receiver system carried by the parent and the child
    • G08B21/0266System arrangements wherein the object is to detect the exact distance between parent and child or surveyor and item
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W84/00Network topologies
    • H04W84/18Self-organising networks, e.g. ad-hoc networks or sensor networks

Definitions

  • the invention relates generally to RF identification tags and interrogators, that is, to systems for identifying objects by communication between a radio frequency transceiver mounted on each object (RF identification “tag”) and a radio frequency transceiver “interrogator”. More specifically, the invention relates to such a system in which one or more human operators each has his own interrogator, and in which the 2-way communication range between each operator's interrogator transceiver and the tags is adjusted so as to prevent communications between the interrogator and more distant tags.
  • Radio frequency identification (RFID) systems have been proposed for identifying tagged objects for such purposes as taking inventory or tracking movements of objects being transported. Examples are described in commonly assigned U.S. Pat. Nos. 5,300,875; 5,365,551; and 5,448,110.
  • RFID systems generally employ a passive or active RF transceiver, called a “tag”, mounted on each object to be identified or tracked.
  • An interrogator transceiver periodically transmits RF interrogation signals.
  • a tag Upon receiving an interrogation signal, a tag responds by transmitting a response signal containing data which identifies the object and contains any other information which may have been stored or programmed in the tag.
  • Conventional RFID systems provide little or no interactive feedback in response to actions performed by handling personnel. Specifically, conventional RFID systems lack any means for discriminating in favor of an individual tagged object a human operator is working with at any given moment; instead, conventional RFID systems generally would confuse the operator by providing information regarding all the tagged objects in the vicinity. Furthermore, if a number of personnel are working close to each other, conventional RFID systems cannot direct information about a tag to the specific individual who is handling the tagged object.
  • the present invention is a method of adjusting the 2-way communication range of an RFID system to assist a human operator to individually handle and interrogate a plurality of tagged objects, such as suitcases, which each include an RFID tag transceiver.
  • An RFID interrogator transceiver preferably mounted on the operator, periodically broadcasts interrogation messages. Any tag transceiver which is within 2-way communication range of the interrogator receives the broadcasted message and responds by transmitting an identifying message containing data identifying the tagged object.
  • the interrogator transceiver receives the response message from the tag and presents to the operator the identifying data contained in the response message, typically via an aural transducer or visual display.
  • the 2-way communication range between the interrogator transceiver and the tag transceivers is adjusted to only slightly exceed the closest distance between the interrogator and the tag while the operator is handling the tagged object. Consequently, other tagged objects will remain outside the communication range and will not respond to interrogation messages. Therefore, the operator can be confident that the identifying information he receives from the interrogator pertains to the individual tagged object which the operator currently is handling, rather than pertaining to other tagged objects nearby.
  • the interrogator transceiver can be mounted anywhere on the operator's person so as to leave both of the operator's hands free for handling the tagged objects.
  • the interrogator can be mounted on the person's belt.
  • the interrogator can have an antenna mounted separately, preferably on the operator's wrist band or similarly near the person's hand, so that the operator can extend his hand toward a tagged object to bring the antenna within close communication range of the RFID tag on the object. This allows reducing the communication range so as to minimize the possibility of responses from RFID tags other than the one associated with the individual tagged object which the operator currently is handling.
  • a second embodiment of the invention does not necessarily limit the interrogator to communicating with a single tag as in the first embodiment. Instead, an objective of the second embodiment is to prevent one operator's interrogator from communicating with tagged objects being handled by other operators working nearby in the same facility.
  • the 2-way communication range between one operator's interrogator and the tags is adjusted so that all tagged objects being handled by other operator personnel are outside the range. Unlike the first embodiment, the 2-way communication range between the interrogator and the tags need not be so short that only one tagged object at a time can be within the range.
  • FIG. 1 is a schematic depiction of an airport baggage sorting facility employing the present invention.
  • FIG. 2 is a block diagram of an REID tag transceiver used in the present invention.
  • FIG. 3 is a block diagram of an RFID interrogator transceiver used in the present invention.
  • FIG. 4 is a schematic depiction of the reliable, unreliable, and zero two-way communications zones surrounding an interrogator transceiver.
  • the invention will be described in the context of an exemplary implementation, depicted in FIG. 1 , in which the human operators 10 are baggage handler personnel working in an airport baggage sorting facility, and the tagged objects 12 are airline baggage.
  • the invention is equally applicable to any other objects to which RFID tags may be attached.
  • a number of baggage handler personnel 10 are responsible for loading a large number of suitcases 12 and other baggage pieces into various freight containers 14 , where each freight container has been designated to be loaded on a specific aircraft flight.
  • An operator's job is to read the designated flight number and/or destination from a tag 16 attached to each suitcase and then to load the suitcase in the correct freight container.
  • Personnel at the airport passenger check-in counter attach an RFID tag 16 to each suitcase 12 .
  • the RFID tag is mounted near a handle 18 of the suitcase so that an operator's hand will be as close as possible to the tag when the operator grasps the handle to pick up the suitcase.
  • the tag may be attached to the handle by a strap 19 , as shown in FIG. 4 .
  • a semiconductor memory 38 within the tag is programmed to store information on the itinerary of the suitcase, such as flight number, time, and destination.
  • the tag's memory may be programmed with additional information such as the name of the owner and special handling instructions.
  • the tag's memory can be programmed by any conventional means for storing data in a memory device connected to an RF transceiver.
  • the RF communications protocol used by the tag transceiver can include commands for storing data, so that such commands could be transmitted to the tag's transceiver by a transmitter used by airport check-in personnel.
  • the tag may include physical connectors for connecting the tag to a conventional memory programming apparatus used by airport check-in personnel.
  • the sorting facility includes a plurality of freight containers 14 , each container being labelled with the flight number of an aircraft whose baggage is to be loaded into that container by the baggage handler personnel (i.e., the operators). After the operators load the appropriate baggage into a container, the container is wheeled from the baggage sorting facility to the aircraft, where other baggage handler personnel transfer the baggage from the container to the aircraft. The process is performed in reverse when the aircraft reaches its destination.
  • Each baggage handling operator 10 in the sorting facility carries a battery-powered RFID interrogator transceiver 20 , the interrogator preferably being attached to the operator's body or clothing so as to leave the operator's hands free and not obstruct the operator's movements.
  • the interrogator may be attached to a belt 22 worn around the operator's waist. (Alternatively, the interrogator may be attached to a strap or belt worn around the operator's leg, arm, or wrist.)
  • the tag 16 on the suitcase receives an interrogation signal transmitted periodically from the operator's interrogator 20 .
  • the tag 16 responds by transmitting a message containing the itinerary information stored in the tag's memory.
  • the interrogator 20 receives the message and conveys the itinerary information to the operator, preferably either visually or aurally. The operator uses the itinerary information to decide which freight container 14 the suitcase should be loaded into.
  • each of the personnel who unload baggage from the airplane preferably also carries an RFID interrogator 20 attached as described above.
  • Each interrogator carried by the unloading personnel would include memory in which a code representing the city (or airport) in which the interrogator is actually located.
  • the interrogator periodically broadcasts interrogation messages and receives a response from each tagged object picked up by the person carrying the interrogator.
  • the control logic 56 in the interrogator is programmed to compare the intended destination city transmitted by each tag with the interrogator's actual location city stored in memory 58 . If the intended and actual destinations do not match, the interrogator presents a warning signal to the unloading person to alert him that the piece of baggage he currently is unloading does not belong in that city.
  • an alternative to each unloading person carrying an interrogator is to mount a single RFID interrogator 20 at each aircraft door through which baggage is unloaded.
  • the interrogator should announce a warning if a piece of baggage exiting the door has an intended destination different from the actual destination stored in the interrogator.
  • the interrogator can be battery-powered for portability, and can be mounted near the aircraft cargo door by any means. Since the interrogator only needs to be mounted during the short time baggage is being unloaded, the mounting means can be temporary.
  • a presently preferred mounting means is a suction cup affixed to the interrogator, allowing it to be temporarily attached to the aircraft skin or door panel.
  • an interrogator transceiver adjacent to a cargo door also is useful when first loading baggage on an aircraft to verify that no baggage is loaded which was intended for a different flight.
  • the airplane flight number or similar identification should be stored in the interrogator's memory 58 .
  • the control logic 56 in the interrogator should be programmed to compare the intended flight number transmitted by each tag to the flight number stored in the interrogator memory, and then signal human personnel in the event of a discrepancy.
  • the central computer should include an RF receiver for receiving the data and a memory for storing it.
  • the data stored in the central computer is useful for tracking the progress of baggage in case of an inquiry or a lost object.
  • the RFID tag transceivers 16 and RFID interrogator transceiver 20 used in the present invention can be any conventional RFID (radio frequency identification) transceivers, examples of which are described in U.S. Pat. Nos. 4,075,632 to Baldwin et al.; 4,857,893 to Carroll; 4,862,160 to Ekchian et al.; 5,055,659 to Hendrick et al; 5,144,314 to Malmberg et al.; and 5,245,346 to Nishimura et al. The entire contents of each of these patents is hereby incorporated into this patent application.
  • FIG. 2 shows an RFID tag transceiver 16 suitable for use with the present invention.
  • An antenna 30 connects to the output of a transmitter 32 and to the input of a receiver 34 .
  • a control logic circuit 36 such as a programmable microcomputer, receives data which has been received and demodulated by the receiver 34 , provides data to the transmitter 32 with which the transmitter is to modulate the transmitted RF signal, and provides control signals to both the receiver and the transmitter.
  • the control logic circuit 36 also exchanges data with a memory 38 . All the components just described are conventionally included in an RFID tag transceiver.
  • the tag transceiver optionally includes an RF signal amplitude detector 40 . Such amplitude detectors are well known, but are not conventionally included in RFID transceivers.
  • FIG. 3 shows an RFID interrogator transceiver 20 suitable for use with the present invention.
  • the interrogator has the same components as the tag, namely, an antenna 50 , transmitter 52 , receiver 54 , control logic circuit 56 , memory 58 , and optional RF signal amplitude detector 60 .
  • the operator 10 When the operator 10 receives itinerary information for a suitcase 12 , it is important for the operator to know which suitcase the information pertains to. In the present invention, this is accomplished by limiting the transmitter power and/or the receiver sensitivity of the operator's interrogator, of the tags, or of both so that 2-way communication between the interrogator and the tags is possible only over a very short range. Specifically, the maximum range or distance across which the interrogator 20 and tags 16 can reliably communicate should be adjusted so that it is only slightly greater than the distance between the antenna of the operator's interrogator and the tag attached to the single suitcase the operator is handling. All other suitcases 12 ′ in the baggage handling facility should be outside this range.
  • the distance between the antenna 50 of the operator's interrogator and the tag 16 on a suitcase will be minimum when the operator 10 grasps the suitcase 12 to move it to the container 14 for the appropriate aircraft.
  • the reliable 2-way communication range 70 between an operator's interrogator and the nearby tags should be adjusted to only slightly exceed this minimum distance. Specifically, the reliable 2-way communication range should be adjusted so that (i) a suitcase being grasped or otherwise handled by the baggage handling operator is within the “reliable 2-way communication inner zone” surrounding the interrogator's antenna, and (ii) all other nearby suitcases 12 ′ are outside this inner zone, and preferably are outside the boundary of the “zero 2-way communication” outer zone.
  • An interrogator and tag are considered to be within reliable 2-way communication range of each other only if the tag can reliably receive RF signals from the interrogator and the interrogator can reliably receive RF signals from the tag. If RF signals can be reliably received by the interrogator from the tag, but not by the tag from the interrogator—or vice versa—then only one-way reliable communication is possible, and the interrogator and tag are not considered within reliable 2-way communication range.
  • the reliable 2-way communication range is the lesser of (a) the maximum distance over which the interrogator can reliably receive RF signals from the tag, and (b) the maximum distance over which the tag can reliably receive RF signals from the interrogator.
  • the reliable 2-way communication range can be reduced by reducing the reliable one-way communication range in either direction, that is, by reducing either the tag-to-interrogator one-way range “a” or the interrogator-to-tag one-way range “b” defined in the preceding paragraph.
  • the one-way communication range from the tags to the operator's interrogator can be reduced either by reducing the transmitter power of all the tags which otherwise could be within communication range of the interrogator or by reducing the receiver sensitivity of the interrogator.
  • the one-way communication range from the operator's interrogator to the tags can be reduced either by reducing the transmitter power of the interrogator or by reducing the receiver sensitivity of all the tags which otherwise could be within communication range of the interrogator.
  • the receiver section can include a conventional circuit 40 , 60 for detecting the amplitude of the received signal (i.e., the signal strength), and a comparator which rejects any received signal whose strength is below a certain threshold.
  • the threshold can be adjusted to adjust the communications range.
  • the comparator and threshold are implemented by suitable programming of the control logic circuit 36 , 56 .
  • the adjustments to the transmitter power and/or receiver sensitivity of the tags and interrogators can be made at the time of their manufacture.
  • the adjustments to an interrogator also can be performed when the interrogator is placed in service in a given facility, thereby permitting customization of the communication range based on the actual distances between the interrogator and the tagged objects in that facility.
  • the interrogator can include circuitry for automatically adjusting its transmitter output power and/or receiver sensitivity to achieve 2-way communication with only the single tagged object being handled at a given time.
  • a particularly preferred embodiment of the interrogator transceiver automatically adjusts the 2-way communication range by reducing its transmitter RF output power, thereby attaining the additional advantage of reducing its battery consumption.
  • the interrogator transceiver initially broadcasts an interrogation signal at a very low transmitter RF output power level. If no tag responds, the interrogator broadcasts the interrogation signal again at a higher power level. If again no tag responds, the interrogator broadcasts the interrogation signal at progressively higher power levels until either a tag responds or the interrogator reaches its maximum transmitter output power. In the latter case, the interrogator waits a certain period of time (for example, 0.2 second), then repeats the process starting with the lowest power level.
  • a certain period of time for example, 0.2 second
  • the interrogator When a tag does respond to an interrogation signal which the interrogator transmitted at a given power level, the interrogator maintains that power level for all subsequent transmissions to that tag. Thus, the interrogator employs the lowest transmitter power needed to communicate with the tag, thereby minimizing power drain from the interrogator's battery. Furthermore, when the interrogator or its antenna is close to a tag (as when the operator is grasping or handling a tagged object), this embodiment of the interrogator inherently adjusts its transmitter output power to a level just high enough to reliably communicate with the closest tag, but not high enough to communicate with other, more distant tags. Therefore, this embodiment of the interrogator performs automatically the adjustment of 2-way communication range described earlier. The adjustment steps preferably are implemented by programming the control logic circuit 56 .
  • each tag is a passive RF transceiver, also called a modulated backscatter RF transceiver.
  • a passive RF transceiver also called a modulated backscatter RF transceiver.
  • Such a transceiver responds to an interrogator signal by modulating the RF carrier of the interrogator signal with the itinerary information and reflecting or re-radiating the modulated signal back toward the interrogator. Examples of modulated backscatter transceivers are described in U.S. Pat. No. 3,832,530 issued Aug. 27, 1974 to Reitboeck et al.; U.S. Pat. No. 4,075,632 issued Feb. 21, 1978 to Baldwin et al.; U.S. Pat. No.
  • the mounting location of the antenna 50 of the interrogator also affects the ability of the interrogator to discriminate against suitcases other than the one currently being handled by the operator.
  • the most convenient and unobtrusive location of the antenna typically is in the same housing as the interrogator transceiver 20 , which, as described above, may be attached to the operator's clothing such as a belt 22 worn around the operator's waist.
  • the distance from the operator's torso to the suitcase being handled should be much smaller than the distance from the operator's torso to any nearby suitcases. If the suitcases are too close together to satisfy this condition, then it is preferable to mount the antenna of the interrogator transceiver on the operator's hand, wrist, or forearm so that the operator can extend his arm toward the tag mounted on the individual suitcase the operator currently is handling, thereby reducing the distance between interrogator antenna and the tag.
  • the antenna 50 of the interrogator transceiver can be mounted in a wrist strap worn on the operator's wrist (see FIG. 4 ). If the tag is attached to the handle of a suitcase, then the interrogator antenna will be closest to the tag (a distance of only two or three inches) when the operator grasps the suitcase handle.
  • the 2-way communication range between the interrogator and tags should be adjusted, as described above, so that the “reliable 2-way communications inner zone” is only slightly greater than this closest distance (i.e., a few inches).
  • the “zero 2-way communication outer zone” boundary is on the order of one foot from the interrogator antenna, whereby the suitcase being handled will be within the inner zone and all other suitcases will be outside the boundary of the outer zone.
  • the antenna and interrogator can be fabricated as an integral unit which is mounted on the operator's hand, wrist, or forearm, if the interrogator is small enough to be worn comfortably in this manner.
  • the tag will receive an interrogation signal from the interrogator and will respond with a message identifying itself to the interrogator.
  • the interrogator then should present to the operator relevant portions of the identifying information, such as airline flight number or destination.
  • the information can be presented aurally or visually.
  • the identifying information can be presented aurally through a loudspeaker mounted in the same enclosure as the interrogator. More preferably, to prevent operators in the same vicinity from disturbing each other, the information can be presented through headphones or similar sound transducers worn or in or adjacent to the operator's ears. Alternatively, the information can be presented visually by a small video display panel mounted on the same enclosure as the interrogator or, more preferably, by a conventional heads-up display incorporated in eye goggles or eyeglasses worn by the operator.
  • the information the interrogator presents to the baggage handling operator when he picks up a suitcase typically would be the flight number of the aircraft on which the suitcase belongs and the destination city of the suitcase. Using this information, the operator then loads the suitcase into the container or truck designated for that flight number.
  • the invention also is useful for baggage handling operators who unload suitcases from an arriving aircraft. Because a given flight typically stops in several destination cities, the baggage unloading operators in a given destination city must ensure they only unload baggage whose intended destination is that city.
  • the name or identification code for the current city should be stored in a semiconductor memory in each operator's interrogator.
  • the interrogator should be programmed to compare the stored city code with the destination city information transmitted by each tagged object handled by the operator. In case the intended destination transmitted by a tag differs from the actual destination stored in the interrogator's memory, the interrogator should present an audible or visual error warning to the operator. For example, the interrogator might contain a green light which flashes when the operator picks up a suitcase whose tag designates the same destination stored in the interrogator, and a red light which flashes when the tag designates a different destination.
  • each operator can share a central control center 80 located in their work area.
  • the interrogator of each operator can transmit RF signals to the central control center using the same transceiver which the interrogator uses to communicate with the tags. Specifically, each interrogator should transmit to the control center RF message signals containing the identifying information received from tags plus the interrogator's own identification number.
  • the control center can display the information received from all the operators' interrogators on a single video display 82 , or the control center can present the information in audible form over a loudspeaker 84 which all the operators in the vicinity can hear.
  • each tag should be accompanied by the name or other identification of the operator who is handling the tagged suitcase, that is, the operator whose interrogator received the information from the tag. For example, in a video display, each operator's name 86 should be displayed next to the identifying information 88 from the tag of the suitcase he currently is handling. With an audio transducer, each operator's name should be pronounced immediately before presenting the identifying information for the suitcase that operator currently is handling.
  • the control center 80 can include a computer which functions as a central database which stores a record of which suitcases have been handled and by which operators.
  • the central database can be used to track the progress of the suitcases from one location to another. In case a suitcase is misdirected, the database can help identify which operator was responsible for the error.
  • An alternative embodiment of the invention does not necessarily limit the interrogator to communicating with a single tag as in the preceding embodiments. Instead, the objective of this alternative embodiment is to prevent one operator's interrogator from communicating with tagged objects being handled by other operators working nearby in the same facility.
  • the 2-way communication range between one operator's interrogator and the tags is adjusted so that all tagged objects being handled by other operator personnel are outside the range. As in the preceding embodiments, the adjustment may be performed by adjusting the transmitter output power and/or the receiver sensitivity in the interrogator transceiver, in the RFID tags, or in both. Unlike the preceding embodiments, the 2-way communication range between the interrogator and the tags need not be so short that only one tagged object at a time can be within the range.
  • the invention has been described in the context of an aircraft baggage handling facility. Nevertheless, the invention is equally useful in other transportation facilities for sorting or handling cargo or goods to be transported in vehicles other than airplanes. More generally, the invention is equally useful in any facility in which human operators handle or monitor any type of objects to which conventional RFID tags can be affixed.

Abstract

A method of adjusting the 2-way communication range of an RFID system to assist a human operator to individually handle and interrogate a plurality of tagged objects, such as suitcases, that each include an RFID tag transceiver. An RFID interrogator transceiver is mounted on the human operator. The 2-way communication range between the interrogator transceiver and the tag transceivers is adjusted to only slightly exceed the closest distance between the interrogator and the tag while the operator is handling the tagged object. Preferably, the 2-way communication range is short enough that other tagged objects will remain outside the communication range and will not respond to messages from the interrogator. Another aspect of the invention is a method of verifying whether an object to be transported has reached its intended destination. In this aspect, an interrogator transceiver at a first destination interrogates an RFID tag transceiver on the object, and in response the tag transmits its intended destination.

Description

    FIELD OF THE INVENTION
  • The invention relates generally to RF identification tags and interrogators, that is, to systems for identifying objects by communication between a radio frequency transceiver mounted on each object (RF identification “tag”) and a radio frequency transceiver “interrogator”. More specifically, the invention relates to such a system in which one or more human operators each has his own interrogator, and in which the 2-way communication range between each operator's interrogator transceiver and the tags is adjusted so as to prevent communications between the interrogator and more distant tags.
  • BACKGROUND OF THE INVENTION
  • Radio frequency identification (RFID) systems have been proposed for identifying tagged objects for such purposes as taking inventory or tracking movements of objects being transported. Examples are described in commonly assigned U.S. Pat. Nos. 5,300,875; 5,365,551; and 5,448,110.
  • RFID systems generally employ a passive or active RF transceiver, called a “tag”, mounted on each object to be identified or tracked. An interrogator transceiver periodically transmits RF interrogation signals. Upon receiving an interrogation signal, a tag responds by transmitting a response signal containing data which identifies the object and contains any other information which may have been stored or programmed in the tag.
  • Conventional RFID systems provide little or no interactive feedback in response to actions performed by handling personnel. Specifically, conventional RFID systems lack any means for discriminating in favor of an individual tagged object a human operator is working with at any given moment; instead, conventional RFID systems generally would confuse the operator by providing information regarding all the tagged objects in the vicinity. Furthermore, if a number of personnel are working close to each other, conventional RFID systems cannot direct information about a tag to the specific individual who is handling the tagged object.
  • For example, suppose a number of airport baggage handler personnel are sorting or routing tagged suitcases according to the airline flight destination encoded in a tag attached to each suitcase. Conventional RFID systems lack any means for detecting which individual suitcase a human operator or baggage handler is about to pick up so as to provide to the operator only the destination or routing information for the suitcase that person currently is handling, to the exclusion of information about other nearby suitcases. Presumably because of this and other shortcomings of conventional RFID systems, RFID tags never entered commercial use for tagging airline baggage.
  • SUMMARY OF THE INVENTION
  • The present invention is a method of adjusting the 2-way communication range of an RFID system to assist a human operator to individually handle and interrogate a plurality of tagged objects, such as suitcases, which each include an RFID tag transceiver. An RFID interrogator transceiver, preferably mounted on the operator, periodically broadcasts interrogation messages. Any tag transceiver which is within 2-way communication range of the interrogator receives the broadcasted message and responds by transmitting an identifying message containing data identifying the tagged object. The interrogator transceiver receives the response message from the tag and presents to the operator the identifying data contained in the response message, typically via an aural transducer or visual display.
  • In a first embodiment of the present invention, the 2-way communication range between the interrogator transceiver and the tag transceivers is adjusted to only slightly exceed the closest distance between the interrogator and the tag while the operator is handling the tagged object. Consequently, other tagged objects will remain outside the communication range and will not respond to interrogation messages. Therefore, the operator can be confident that the identifying information he receives from the interrogator pertains to the individual tagged object which the operator currently is handling, rather than pertaining to other tagged objects nearby.
  • The interrogator transceiver can be mounted anywhere on the operator's person so as to leave both of the operator's hands free for handling the tagged objects. For example, the interrogator can be mounted on the person's belt. Furthermore, the interrogator can have an antenna mounted separately, preferably on the operator's wrist band or similarly near the person's hand, so that the operator can extend his hand toward a tagged object to bring the antenna within close communication range of the RFID tag on the object. This allows reducing the communication range so as to minimize the possibility of responses from RFID tags other than the one associated with the individual tagged object which the operator currently is handling.
  • A second embodiment of the invention does not necessarily limit the interrogator to communicating with a single tag as in the first embodiment. Instead, an objective of the second embodiment is to prevent one operator's interrogator from communicating with tagged objects being handled by other operators working nearby in the same facility. In this embodiment, the 2-way communication range between one operator's interrogator and the tags is adjusted so that all tagged objects being handled by other operator personnel are outside the range. Unlike the first embodiment, the 2-way communication range between the interrogator and the tags need not be so short that only one tagged object at a time can be within the range.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a schematic depiction of an airport baggage sorting facility employing the present invention.
  • FIG. 2 is a block diagram of an REID tag transceiver used in the present invention.
  • FIG. 3 is a block diagram of an RFID interrogator transceiver used in the present invention.
  • FIG. 4 is a schematic depiction of the reliable, unreliable, and zero two-way communications zones surrounding an interrogator transceiver.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1. Overview
  • The invention will be described in the context of an exemplary implementation, depicted in FIG. 1, in which the human operators 10 are baggage handler personnel working in an airport baggage sorting facility, and the tagged objects 12 are airline baggage. However, the invention is equally applicable to any other objects to which RFID tags may be attached.
  • In the airport example, a number of baggage handler personnel 10, hereinafter called “operators”, are responsible for loading a large number of suitcases 12 and other baggage pieces into various freight containers 14, where each freight container has been designated to be loaded on a specific aircraft flight. An operator's job is to read the designated flight number and/or destination from a tag 16 attached to each suitcase and then to load the suitcase in the correct freight container.
  • Personnel at the airport passenger check-in counter attach an RFID tag 16 to each suitcase 12. Preferably, the RFID tag is mounted near a handle 18 of the suitcase so that an operator's hand will be as close as possible to the tag when the operator grasps the handle to pick up the suitcase. For example, the tag may be attached to the handle by a strap 19, as shown in FIG. 4.
  • A semiconductor memory 38 within the tag is programmed to store information on the itinerary of the suitcase, such as flight number, time, and destination. Optionally, the tag's memory may be programmed with additional information such as the name of the owner and special handling instructions.
  • The tag's memory can be programmed by any conventional means for storing data in a memory device connected to an RF transceiver. For example, the RF communications protocol used by the tag transceiver can include commands for storing data, so that such commands could be transmitted to the tag's transceiver by a transmitter used by airport check-in personnel. Alternatively, the tag may include physical connectors for connecting the tag to a conventional memory programming apparatus used by airport check-in personnel.
  • After mounting an RFID tag on the suitcase, the check-in counter personnel place the suitcase on a conveyor belt 24 which carries the suitcase to a large baggage sorting facility such as the sorting facility shown in FIG. 1. The sorting facility includes a plurality of freight containers 14, each container being labelled with the flight number of an aircraft whose baggage is to be loaded into that container by the baggage handler personnel (i.e., the operators). After the operators load the appropriate baggage into a container, the container is wheeled from the baggage sorting facility to the aircraft, where other baggage handler personnel transfer the baggage from the container to the aircraft. The process is performed in reverse when the aircraft reaches its destination.
  • Each baggage handling operator 10 in the sorting facility carries a battery-powered RFID interrogator transceiver 20, the interrogator preferably being attached to the operator's body or clothing so as to leave the operator's hands free and not obstruct the operator's movements. For example, the interrogator may be attached to a belt 22 worn around the operator's waist. (Alternatively, the interrogator may be attached to a strap or belt worn around the operator's leg, arm, or wrist.) As the operator moves within a certain proximity of an individual suitcase 12, the tag 16 on the suitcase receives an interrogation signal transmitted periodically from the operator's interrogator 20. The tag 16 responds by transmitting a message containing the itinerary information stored in the tag's memory. The interrogator 20 receives the message and conveys the itinerary information to the operator, preferably either visually or aurally. The operator uses the itinerary information to decide which freight container 14 the suitcase should be loaded into.
  • When the aircraft reaches its destination, each of the personnel who unload baggage from the airplane preferably also carries an RFID interrogator 20 attached as described above. Each interrogator carried by the unloading personnel would include memory in which a code representing the city (or airport) in which the interrogator is actually located. The interrogator periodically broadcasts interrogation messages and receives a response from each tagged object picked up by the person carrying the interrogator. The control logic 56 in the interrogator is programmed to compare the intended destination city transmitted by each tag with the interrogator's actual location city stored in memory 58. If the intended and actual destinations do not match, the interrogator presents a warning signal to the unloading person to alert him that the piece of baggage he currently is unloading does not belong in that city.
  • For baggage unloading, an alternative to each unloading person carrying an interrogator is to mount a single RFID interrogator 20 at each aircraft door through which baggage is unloaded. As described in the preceding paragraph, the interrogator should announce a warning if a piece of baggage exiting the door has an intended destination different from the actual destination stored in the interrogator. The interrogator can be battery-powered for portability, and can be mounted near the aircraft cargo door by any means. Since the interrogator only needs to be mounted during the short time baggage is being unloaded, the mounting means can be temporary. A presently preferred mounting means is a suction cup affixed to the interrogator, allowing it to be temporarily attached to the aircraft skin or door panel.
  • Mounting an interrogator transceiver adjacent to a cargo door, as described in the preceding paragraph, also is useful when first loading baggage on an aircraft to verify that no baggage is loaded which was intended for a different flight. For purposes of loading rather than unloading, the airplane flight number or similar identification should be stored in the interrogator's memory 58. The control logic 56 in the interrogator should be programmed to compare the intended flight number transmitted by each tag to the flight number stored in the interrogator memory, and then signal human personnel in the event of a discrepancy.
  • Any of the interrogator transceivers described above can re-transmit data received from tags to a central computer 80. The central computer should include an RF receiver for receiving the data and a memory for storing it. The data stored in the central computer is useful for tracking the progress of baggage in case of an inquiry or a lost object.
  • The RFID tag transceivers 16 and RFID interrogator transceiver 20 used in the present invention can be any conventional RFID (radio frequency identification) transceivers, examples of which are described in U.S. Pat. Nos. 4,075,632 to Baldwin et al.; 4,857,893 to Carroll; 4,862,160 to Ekchian et al.; 5,055,659 to Hendrick et al; 5,144,314 to Malmberg et al.; and 5,245,346 to Nishimura et al. The entire contents of each of these patents is hereby incorporated into this patent application.
  • A preferred physical implementation of an RFID tag transceiver 16 is described in U.S. Pat. Nos. 5,406,263; 5,448,110; and 5,497,140. A preferred protocol for communications between the interrogator 20 and the tags 16 is described in U.S. Pat. No. 5,500,650. The entire contents of each of these patents is hereby incorporated into this patent application.
  • FIG. 2 shows an RFID tag transceiver 16 suitable for use with the present invention. An antenna 30 connects to the output of a transmitter 32 and to the input of a receiver 34. A control logic circuit 36, such as a programmable microcomputer, receives data which has been received and demodulated by the receiver 34, provides data to the transmitter 32 with which the transmitter is to modulate the transmitted RF signal, and provides control signals to both the receiver and the transmitter. The control logic circuit 36 also exchanges data with a memory 38. All the components just described are conventionally included in an RFID tag transceiver. As described below, the tag transceiver optionally includes an RF signal amplitude detector 40. Such amplitude detectors are well known, but are not conventionally included in RFID transceivers.
  • FIG. 3 shows an RFID interrogator transceiver 20 suitable for use with the present invention. The interrogator has the same components as the tag, namely, an antenna 50, transmitter 52, receiver 54, control logic circuit 56, memory 58, and optional RF signal amplitude detector 60.
  • 2. Excluding Nearby Tags from Communication Range
  • When the operator 10 receives itinerary information for a suitcase 12, it is important for the operator to know which suitcase the information pertains to. In the present invention, this is accomplished by limiting the transmitter power and/or the receiver sensitivity of the operator's interrogator, of the tags, or of both so that 2-way communication between the interrogator and the tags is possible only over a very short range. Specifically, the maximum range or distance across which the interrogator 20 and tags 16 can reliably communicate should be adjusted so that it is only slightly greater than the distance between the antenna of the operator's interrogator and the tag attached to the single suitcase the operator is handling. All other suitcases 12′ in the baggage handling facility should be outside this range.
  • More specifically (see FIG. 4), depending on the transmitter power, receiver sensitivity, and antenna radiation pattern of the RFID tags 16 and the interrogator 20, there will be a “reliable 2-way communication” inner zone 70 surrounding the antenna 50 of the operator's interrogator within which an RFID tag 16 will be close enough to reliably communicate with the interrogator, and a “zero 2-way communication” outer zone 72, defined by a boundary 73 surrounding the inner zone, beyond which boundary 73 an RFID tag cannot successfully communicate with the operator's interrogator. Between the respective boundaries 71 and 73 of the inner and outer zones 70 and 72 is an “unreliable 2-way communication” intermediate zone 74 within which a tag can communicate with the interrogator with uncertain reliability.
  • The distance between the antenna 50 of the operator's interrogator and the tag 16 on a suitcase will be minimum when the operator 10 grasps the suitcase 12 to move it to the container 14 for the appropriate aircraft. The reliable 2-way communication range 70 between an operator's interrogator and the nearby tags should be adjusted to only slightly exceed this minimum distance. Specifically, the reliable 2-way communication range should be adjusted so that (i) a suitcase being grasped or otherwise handled by the baggage handling operator is within the “reliable 2-way communication inner zone” surrounding the interrogator's antenna, and (ii) all other nearby suitcases 12′ are outside this inner zone, and preferably are outside the boundary of the “zero 2-way communication” outer zone. If the 2-way communications range is adjusted according to these criteria, only the tag on the single suitcase currently being handled will be close enough for 2-way communication with the operator's interrogator. Therefore, the operator can be confident that the identifying information he receives from the interrogator pertains to the individual suitcase 12 the operator currently is handling, rather than pertaining to other suitcases 12′ nearby.
  • An interrogator and tag are considered to be within reliable 2-way communication range of each other only if the tag can reliably receive RF signals from the interrogator and the interrogator can reliably receive RF signals from the tag. If RF signals can be reliably received by the interrogator from the tag, but not by the tag from the interrogator—or vice versa—then only one-way reliable communication is possible, and the interrogator and tag are not considered within reliable 2-way communication range. In other words, the reliable 2-way communication range is the lesser of (a) the maximum distance over which the interrogator can reliably receive RF signals from the tag, and (b) the maximum distance over which the tag can reliably receive RF signals from the interrogator.
  • Consequently, the reliable 2-way communication range can be reduced by reducing the reliable one-way communication range in either direction, that is, by reducing either the tag-to-interrogator one-way range “a” or the interrogator-to-tag one-way range “b” defined in the preceding paragraph.
  • The one-way communication range from the tags to the operator's interrogator (range “a” defined above) can be reduced either by reducing the transmitter power of all the tags which otherwise could be within communication range of the interrogator or by reducing the receiver sensitivity of the interrogator. Conversely, the one-way communication range from the operator's interrogator to the tags (range “b” defined above) can be reduced either by reducing the transmitter power of the interrogator or by reducing the receiver sensitivity of all the tags which otherwise could be within communication range of the interrogator.
  • There are various conventional circuit designs for adjusting transmitter output power or receiver sensitivity. For example, to permit adjusting the sensitivity of the receiver section of each tag and/or the interrogator, the receiver section can include a conventional circuit 40, 60 for detecting the amplitude of the received signal (i.e., the signal strength), and a comparator which rejects any received signal whose strength is below a certain threshold. The threshold can be adjusted to adjust the communications range. Preferably, the comparator and threshold are implemented by suitable programming of the control logic circuit 36, 56.
  • The adjustments to the transmitter power and/or receiver sensitivity of the tags and interrogators can be made at the time of their manufacture. The adjustments to an interrogator also can be performed when the interrogator is placed in service in a given facility, thereby permitting customization of the communication range based on the actual distances between the interrogator and the tagged objects in that facility. Alternatively, the interrogator can include circuitry for automatically adjusting its transmitter output power and/or receiver sensitivity to achieve 2-way communication with only the single tagged object being handled at a given time.
  • A particularly preferred embodiment of the interrogator transceiver automatically adjusts the 2-way communication range by reducing its transmitter RF output power, thereby attaining the additional advantage of reducing its battery consumption. In this embodiment, the interrogator transceiver initially broadcasts an interrogation signal at a very low transmitter RF output power level. If no tag responds, the interrogator broadcasts the interrogation signal again at a higher power level. If again no tag responds, the interrogator broadcasts the interrogation signal at progressively higher power levels until either a tag responds or the interrogator reaches its maximum transmitter output power. In the latter case, the interrogator waits a certain period of time (for example, 0.2 second), then repeats the process starting with the lowest power level.
  • When a tag does respond to an interrogation signal which the interrogator transmitted at a given power level, the interrogator maintains that power level for all subsequent transmissions to that tag. Thus, the interrogator employs the lowest transmitter power needed to communicate with the tag, thereby minimizing power drain from the interrogator's battery. Furthermore, when the interrogator or its antenna is close to a tag (as when the operator is grasping or handling a tagged object), this embodiment of the interrogator inherently adjusts its transmitter output power to a level just high enough to reliably communicate with the closest tag, but not high enough to communicate with other, more distant tags. Therefore, this embodiment of the interrogator performs automatically the adjustment of 2-way communication range described earlier. The adjustment steps preferably are implemented by programming the control logic circuit 56.
  • In a preferred embodiment of the RFID tags, which advantageously limits the 2-way communication range between the tags and the interrogator, each tag is a passive RF transceiver, also called a modulated backscatter RF transceiver. Such a transceiver responds to an interrogator signal by modulating the RF carrier of the interrogator signal with the itinerary information and reflecting or re-radiating the modulated signal back toward the interrogator. Examples of modulated backscatter transceivers are described in U.S. Pat. No. 3,832,530 issued Aug. 27, 1974 to Reitboeck et al.; U.S. Pat. No. 4,075,632 issued Feb. 21, 1978 to Baldwin et al.; U.S. Pat. No. 4,857,893 issued Aug. 15, 1989 to Carroll; and U.S. Pat. No. 5,313,211 issued May 17, 1994 to Tokuda et al.; the entire contents of each of which are hereby incorporated into this patent specification. The amplitude of the RF signal received by the interrogator from a modulated backscatter tag will decline approximately in proportion to the fourth power of the distance between the respective antennas of the tag and the interrogator, assuming both antennas are fairly omnidirectional. In contrast, if the tags had active transmitters with fixed output power, the amplitude would decline only in proportion to the square of the distance.
  • Using the just described RFID tags with modulated backscatter RF transceivers in combination with the previously described preferred interrogator with automatically adjusting transmitter power, I have found that the interrogator reliably communicates with a tagged suitcase 12 when it is grasped by a human operator, while reliably ignoring the tags on other suitcases 12′ nearby.
  • 3. Antenna Location
  • The mounting location of the antenna 50 of the interrogator also affects the ability of the interrogator to discriminate against suitcases other than the one currently being handled by the operator. The most convenient and unobtrusive location of the antenna typically is in the same housing as the interrogator transceiver 20, which, as described above, may be attached to the operator's clothing such as a belt 22 worn around the operator's waist. With the interrogator and its antenna mounted on the operator's torso, the required 2-way communication range between the interrogator and the tag depends on how close the operator's torso approaches the suitcase during normal handling.
  • To prevent tags on adjacent suitcases from responding to the interrogator, the distance from the operator's torso to the suitcase being handled should be much smaller than the distance from the operator's torso to any nearby suitcases. If the suitcases are too close together to satisfy this condition, then it is preferable to mount the antenna of the interrogator transceiver on the operator's hand, wrist, or forearm so that the operator can extend his arm toward the tag mounted on the individual suitcase the operator currently is handling, thereby reducing the distance between interrogator antenna and the tag.
  • For example, the antenna 50 of the interrogator transceiver can be mounted in a wrist strap worn on the operator's wrist (see FIG. 4). If the tag is attached to the handle of a suitcase, then the interrogator antenna will be closest to the tag (a distance of only two or three inches) when the operator grasps the suitcase handle. The 2-way communication range between the interrogator and tags should be adjusted, as described above, so that the “reliable 2-way communications inner zone” is only slightly greater than this closest distance (i.e., a few inches). Preferably, a consequence of this adjustment is that the “zero 2-way communication outer zone” boundary is on the order of one foot from the interrogator antenna, whereby the suitcase being handled will be within the inner zone and all other suitcases will be outside the boundary of the outer zone.
  • The antenna and interrogator can be fabricated as an integral unit which is mounted on the operator's hand, wrist, or forearm, if the interrogator is small enough to be worn comfortably in this manner.
  • 4. Interrogator Presentation of Information to Operator
  • As described above, when a human operator approaches close enough to a tagged suitcase for the operator's interrogator and the tag to be within 2-way communication range, the tag will receive an interrogation signal from the interrogator and will respond with a message identifying itself to the interrogator. The interrogator then should present to the operator relevant portions of the identifying information, such as airline flight number or destination. The information can be presented aurally or visually.
  • Specifically, the identifying information can be presented aurally through a loudspeaker mounted in the same enclosure as the interrogator. More preferably, to prevent operators in the same vicinity from disturbing each other, the information can be presented through headphones or similar sound transducers worn or in or adjacent to the operator's ears. Alternatively, the information can be presented visually by a small video display panel mounted on the same enclosure as the interrogator or, more preferably, by a conventional heads-up display incorporated in eye goggles or eyeglasses worn by the operator.
  • In the previously described example of an aircraft baggage sorting facility for loading baggage onto departing aircraft, the information the interrogator presents to the baggage handling operator when he picks up a suitcase typically would be the flight number of the aircraft on which the suitcase belongs and the destination city of the suitcase. Using this information, the operator then loads the suitcase into the container or truck designated for that flight number.
  • The invention also is useful for baggage handling operators who unload suitcases from an arriving aircraft. Because a given flight typically stops in several destination cities, the baggage unloading operators in a given destination city must ensure they only unload baggage whose intended destination is that city. For this application, the name or identification code for the current city should be stored in a semiconductor memory in each operator's interrogator. The interrogator should be programmed to compare the stored city code with the destination city information transmitted by each tagged object handled by the operator. In case the intended destination transmitted by a tag differs from the actual destination stored in the interrogator's memory, the interrogator should present an audible or visual error warning to the operator. For example, the interrogator might contain a green light which flashes when the operator picks up a suitcase whose tag designates the same destination stored in the interrogator, and a red light which flashes when the tag designates a different destination.
  • As an alternative to each operator's carrying or wearing an audio transducer or video display as just described, several operators working in the same area or facility can share a central control center 80 located in their work area. The interrogator of each operator can transmit RF signals to the central control center using the same transceiver which the interrogator uses to communicate with the tags. Specifically, each interrogator should transmit to the control center RF message signals containing the identifying information received from tags plus the interrogator's own identification number. The control center can display the information received from all the operators' interrogators on a single video display 82, or the control center can present the information in audible form over a loudspeaker 84 which all the operators in the vicinity can hear.
  • If multiple operator personnel share a central audio transducer or visual display, the presentation of information from each tag should be accompanied by the name or other identification of the operator who is handling the tagged suitcase, that is, the operator whose interrogator received the information from the tag. For example, in a video display, each operator's name 86 should be displayed next to the identifying information 88 from the tag of the suitcase he currently is handling. With an audio transducer, each operator's name should be pronounced immediately before presenting the identifying information for the suitcase that operator currently is handling.
  • Whether or not a shared control center presents information to the operators as just described, the control center 80 can include a computer which functions as a central database which stores a record of which suitcases have been handled and by which operators. The central database can be used to track the progress of the suitcases from one location to another. In case a suitcase is misdirected, the database can help identify which operator was responsible for the error.
  • 5. Embodiment for Discriminating Among Operator Personnel
  • An alternative embodiment of the invention does not necessarily limit the interrogator to communicating with a single tag as in the preceding embodiments. Instead, the objective of this alternative embodiment is to prevent one operator's interrogator from communicating with tagged objects being handled by other operators working nearby in the same facility. In this embodiment, the 2-way communication range between one operator's interrogator and the tags is adjusted so that all tagged objects being handled by other operator personnel are outside the range. As in the preceding embodiments, the adjustment may be performed by adjusting the transmitter output power and/or the receiver sensitivity in the interrogator transceiver, in the RFID tags, or in both. Unlike the preceding embodiments, the 2-way communication range between the interrogator and the tags need not be so short that only one tagged object at a time can be within the range.
  • 6. Conclusion
  • The invention has been described in the context of an aircraft baggage handling facility. Nevertheless, the invention is equally useful in other transportation facilities for sorting or handling cargo or goods to be transported in vehicles other than airplanes. More generally, the invention is equally useful in any facility in which human operators handle or monitor any type of objects to which conventional RFID tags can be affixed.

Claims (42)

1-27. (canceled)
28: A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, the method comprising:
mounting on the person an RFID interrogator transceiver having an antenna configured to be worn by the person;
mounting on each tagged object an RFID tag transceiver, wherein
each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and
the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and
adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects only slightly exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object.
29: A method in accordance with claim 28 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.
30: A method in accordance with claim 29 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.
31: A method in accordance with claim 28, wherein:
the performance parameters of each tag transceiver include a receiver sensitivity of the tag transceiver;
the performance parameters of the interrogator transceiver include a receiver sensitivity of the interrogator transceiver and a transmitter output power of the interrogator transceiver; and
the adjusting step includes adjusting at least one of the receiver sensitivity of the tag transceiver, the receiver sensitivity of the interrogator transceiver, and the transmitter output power of the interrogator transceiver.
32: A method in accordance with claim 28, wherein each tag transceiver is a modulated backscatter transceiver.
33: A method in accordance with claim 28, further comprising the steps of:
the interrogator transceiver transmitting an interrogation message while the person is close enough to a tagged object for the antenna of the interrogator transceiver and that transceiver of the tagged object to be within the communications range;
the transceiver of that tagged object transmitting, in response to the interrogation message, an identification message containing data identifying that tagged object; and
the interrogator transceiver receiving the identification message and presenting the data to said person.
34: A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising:
supporting on the person a portable RFID interrogator transceiver;
mounting on each tagged object an RFID tag transceiver, wherein
each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and
the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers;
iteratively
transmitting an interrogation signal via the RFID interrogator;
determining at the RFID interrogator, based either on one or more response messages sent by the RFID tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting at least one of the interrogator performance parameters or the transceiver performance parameters;
until the RFID tag transceiver of one of the tagged objects being individually handled by the person is within the reliable two-way communications range and the tag transceivers of the tagged objects not being individually handled are not within the reliable two-way communications range; and
wherein, in operation, the interrogator presents to the person an audio indication of data received from an interrogated tag.
35: A method in accordance with claim 34 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.
36: A method in accordance with claim 35 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.
37: A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:
mounting on the person an RFID interrogator transceiver having an antenna, with the antenna being configured to be worn by the person;
mounting on each tagged object an RFID tag transceiver, wherein
each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and
the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers, and
adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object;
wherein the adjusting step further comprises adjusting said at least one of the performance parameters so that said reliable two-way communications range is short enough so that, when the person handles a tagged object, no other tagged object is within reliable two-way communication range of the interrogator.
38: A method in accordance with claim 37 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.
39: A method in accordance with claim 38 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.
40: A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:
mounting adjacent the person an RFID interrogator transceiver having an antenna;
mounting on each tagged object an RFID tag transceiver, wherein
each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and
the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and
adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects only slightly exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and that tagged object.
41: A method in accordance with claim 40, wherein the step of mounting the interrogator transceiver further comprises:
mounting the interrogator transceiver on the person so as to leave the hands of the person free to grasp objects other than the interrogator transceiver.
42: An RFID interrogator apparatus having an adjustable reliable two-way communication range so as to permit a person to individually interrogate the closest one of a plurality of nearby tagged objects, wherein each tagged object has a respective RFID tag transceiver attached thereto, comprising:
an RFID interrogator transceiver, configured to communicate with any of the RFID tag transmitters, including a transmitter and receiver and having adjustable transmitter power and adjustable receiver sensitivity;
an antenna coupled to the interrogator transceiver and which is adapted to be worn by a person, on the person's torso; and
a control logic circuit, connected to the interrogator transceiver, for iteratively transmitting an interrogation signal via the transmitter;
determining, based either on one or more response messages sent by the RFID tag transceivers to the RFID interrogator transceiver in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting the transmitter power or receiver sensitivity;
until the RFID tag transceiver of the closest one of the tagged objects is within the reliable two-way communications range and the tag transceivers of the other tagged objects are not within the reliable two-way communications range.
43: The apparatus of claim 42 wherein the adjusting the transmitter power or receiver sensitivity comprises adjusting the transmitter power.
44: The apparatus of claim 43 wherein the control logic circuit is configured to select the transmitter power from among at least three different possible power levels.
45: An RFID interrogator apparatus having an adjustable two-way communication range so as to permit a person to individually interrogate the closest one of a plurality of nearby tagged objects, wherein each tagged object has a respective RFID tag transceiver attached thereto, comprising:
an RFID interrogator transceiver characterized by a set of one or more performance parameters which control a reliable two-way communications range between the interrogator transceiver and any of the RFID tag transceivers;
an antenna coupled to the interrogator transceiver and which is adapted to be worn by a person; and
a control logic circuit, connected to the interrogator transceiver, for adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceivers exceeds the closest distance, during times when said person handles a tagged object, between the antenna and the tag transceiver attached to that tagged object;
wherein the interrogator transceiver includes circuitry for detecting signal strength and circuitry for rejecting a signal whose strength is below a threshold signal strength.
46: The apparatus of claim 45 wherein the adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.
47: The apparatus of claim 46 wherein the interrogator transmitter output power is selectable from among at least three different possible power levels.
48: A method in accordance with claim 50 wherein adjusting interrogator power comprises adjusting interrogator transmitter output power.
49: A method in accordance with claim 48 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.
50: A method comprising:
mounting on an airplane cargo door an RFID interrogator transceiver;
mounting on pieces of luggage respective RFID tag transceivers, wherein
each tag transceiver has adjustable sensitivity, and
the interrogator transceiver has adjustable power output; and iteratively
transmitting an interrogation signal via the RFID interrogator transceiver;
determining at the RFID interrogator transceiver, based either on one or more response messages sent by the RFID tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the pieces of luggage are within a reliable two-way communications range; and
adjusting the RFID interrogator transceiver power output or the sensitivity of the tag transceiver;
until the RFID tag transceiver of one of the pieces of luggage passing through the cargo door is within the reliable two-way communications range and the pieces of luggage not passing through the cargo door are not within the reliable two-way communications range.
51: A method of adjusting the two-way communication range of an RFID system to permit a baggage handler to individually handle and interrogate each one of a plurality of tagged luggage items, each tagged luggage item having an RFID tag transceiver, the method comprising:
mounting on the baggage handler an RFID interrogator transceiver having an antenna configured to be worn by the person;
mounting on multiple tagged luggage items an RFID tag transceiver, wherein
respective tag transceivers are characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver;
tag transceivers respectively include memory configured to store data representing the intended destination of the luggage item to which the tag is mounted; and
the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers;
the interrogator transceiver includes a memory configured to store data representing the airport at which the interrogator is being used;
adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects only slightly exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object; and
comparing the data stored in the interrogator transceiver with data stored in a tag transceiver to determine if an item of luggage is at its destination.
52: A method in accordance with claim 51 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.
53: A method in accordance with claim 52 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.
54: The method of claim 28 wherein the antenna is configured to be worn by the person.
55: The method of claim 28 wherein adjusting at least one of the interrogator performance parameters comprises successively transmitting interrogation signals via the interrogator transceiver until the interrogator transceiver, in response to one of the interrogation signals, receives a response from the tagged object being handled by the person, the first interrogation signal being transmitted at a minimum power level and the subsequent interrogation signals being transmitted at successively higher power levels.
56: The method of claim 28 wherein adjusting at least one of the interrogator performance parameters comprises successively transmitting interrogation signals via the interrogator transceiver until the reliable two-way communications range only slightly exceeds the closest distance between the antenna of the interrogator and the tag transceiver mounted on the tagged object being handled by the person, the interrogator transceiver operating at a first level of receive sensitivity subsequent to the first interrogation signal being transmitted and operating at successively reduced levels of receive sensitivity subsequent to the transmission of each successive interrogation signal.
57: The method of claim 28 wherein the adjusting comprises iteratively
transmitting an interrogation signal via the RFID interrogator;
determining at the RFID interrogator, based either on one or more response messages sent by the RFID tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting at least one of the interrogator performance parameters or the transceiver performance parameters;
until the RFID tag transceiver of one of the tagged objects being individually handled by the person is within the reliable two-way communications range and the tag transceivers of the tagged objects not being individually handled are not within the reliable two-way communications range.
58: The method of claim 37 wherein the interrogator transceiver includes memory storing data indicative of a location of the interrogator transceiver, the interrogator transceiver selectively receiving data indicative of an intended destination location of one of the tagged objects from the tag transceiver mounted on the one tagged object.
59: The method of claim 37 wherein the adjusting comprises iteratively
transmitting an interrogation signal via the RFID interrogator;
determining at the RFID interrogator, based either on one or more response messages sent by the RFID tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting at least one of the interrogator performance parameters or the transceiver performance parameters;
until the RFID tag transceiver of one of the tagged objects being individually handled by the person is within the reliable two-way communications range and the tag transceivers of the tagged objects not being individually handled are not within the reliable two-way communications range.
60: The method of claim 40 wherein the adjusting comprises iteratively
transmitting an interrogation signal via the RFID interrogator;
determining at the RFID interrogator, based either on one or more response messages sent by the RFID tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting at least one of the interrogator performance parameters or the transceiver performance parameters;
until the RFID tag transceiver of one of the tagged objects being individually handled by the person is within the reliable two-way communications range and the tag transceivers of the tagged objects not being individually handled are not within the reliable two-way communications range.
61: The apparatus of claim 42 wherein the RFID tag transceivers are modulated backscatter transceivers configured to reflect RF energy received by the respective RFID tag transceivers.
62: The apparatus of claim 45 wherein the control logic circuit is further configured for iteratively
transmitting an interrogation signal via the transceiver;
determining, based either on one or more response messages sent by the RFID tag transceivers to the RFID interrogator transceiver in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged objects are within the reliable two-way communications range; and
adjusting at least one of the performance parameters;
until the RFID tag transceiver of the closest one of the tagged objects is within the reliable two-way communications range and the tag transceivers of the tagged objects are not within the reliable two-way communications range.
63: The method of claim 51 further comprising:
receiving, at the interrogator, the data representing the intended destination of the luggage item to which the tag is mounted from at least one of the tag transceivers and comparing, at the interrogator, the data representing the airport at which the interrogator is being used with the data representing the intended destination of the luggage item; and
if the data representing the airport at which the interrogator is being used and the data representing the intended destination of the luggage item both refer to a same location, notifying the baggage handler.
64: The method of claim 51 wherein the adjusting comprises iteratively
transmitting an interrogation signal via the interrogator;
determining at the interrogator, based either on one or more response messages sent by the tag transceivers to the interrogator in response to the interrogation signal or on the absence of a response to the interrogation signal, which of the tagged luggage items are within the reliable two-way communications range; and
adjusting at least one of the interrogator performance parameters or the tag transceiver performance parameters;
until the RFID tag transceiver of one of the luggage items being individually handled by the baggage handler is within the reliable two-way communications range and the tag transceivers of the luggage not being individually handled are not within the reliable two-way communications range.
65: The method of claim 57 further comprising:
comparing, at the interrogator transceiver, the data indicative of the location of the interrogator transceiver with the data indicative of the intended destination location of the one tagged object; and
if the data indicative of the location of the interrogator transceiver and the data indicative of the intended destination location of the one tagged object both refer to a same location, notifying the person.
66: The method of claim 58 wherein at least one of the tag transceivers is a modulated backscatter transceiver configured to selectively reflect a continuous wave signal having a first frequency, the selectively reflected signal having a second frequency substantially the same as the first frequency.
67: The method of claim 63 wherein at least one of the tag transceivers is a modulated backscatter transceiver.
68: The method of claim 63 wherein the notifying the baggage handler comprises displaying an identifier associated with the baggage handler using a control center, the control center being configured to display identifiers of a plurality of other baggage handlers in addition to the notified baggage handler and to display an identifier associated with the intended destination of the luggage item as well as other identifiers associated with intended destinations of other luggage items handled by the plurality of other baggage handlers, the other identifiers being retrieved by the other baggage handlers using other interrogators.
US12/016,900 1992-12-15 2008-01-18 RFID System and Method for Wirelessly Interfacing With an Interrogator Abandoned US20080117025A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US12/016,900 US20080117025A1 (en) 1992-12-15 2008-01-18 RFID System and Method for Wirelessly Interfacing With an Interrogator
US13/460,694 US20120274450A1 (en) 1996-04-04 2012-04-30 Object tracking rfid systems and methods

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US07/990,915 US5500650A (en) 1992-12-15 1992-12-15 Data communication method using identification protocol
US08/619,274 US5627544A (en) 1992-12-15 1996-03-18 Data communication method using identification protocol
US08/628,125 US6097301A (en) 1996-04-04 1996-04-04 RF identification system with restricted range
US62993300A 2000-08-01 2000-08-01
US10/938,917 US20050040961A1 (en) 1995-04-11 2004-09-09 RF identification system with restricted range
US12/016,900 US20080117025A1 (en) 1992-12-15 2008-01-18 RFID System and Method for Wirelessly Interfacing With an Interrogator

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US10/938,917 Continuation US20050040961A1 (en) 1992-12-15 2004-09-09 RF identification system with restricted range

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US13/460,694 Continuation US20120274450A1 (en) 1996-04-04 2012-04-30 Object tracking rfid systems and methods

Publications (1)

Publication Number Publication Date
US20080117025A1 true US20080117025A1 (en) 2008-05-22

Family

ID=24517581

Family Applications (4)

Application Number Title Priority Date Filing Date
US08/628,125 Expired - Lifetime US6097301A (en) 1992-12-15 1996-04-04 RF identification system with restricted range
US09/631,060 Expired - Fee Related US6842121B1 (en) 1996-04-04 2000-08-01 RF identification system for determining whether object has reached destination
US12/016,900 Abandoned US20080117025A1 (en) 1992-12-15 2008-01-18 RFID System and Method for Wirelessly Interfacing With an Interrogator
US13/460,694 Abandoned US20120274450A1 (en) 1996-04-04 2012-04-30 Object tracking rfid systems and methods

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US08/628,125 Expired - Lifetime US6097301A (en) 1992-12-15 1996-04-04 RF identification system with restricted range
US09/631,060 Expired - Fee Related US6842121B1 (en) 1996-04-04 2000-08-01 RF identification system for determining whether object has reached destination

Family Applications After (1)

Application Number Title Priority Date Filing Date
US13/460,694 Abandoned US20120274450A1 (en) 1996-04-04 2012-04-30 Object tracking rfid systems and methods

Country Status (1)

Country Link
US (4) US6097301A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060202802A1 (en) * 2003-05-12 2006-09-14 Seppae Heikki Remote sensor, device and method for activating selected remote sensor components
US20070066223A1 (en) * 2005-02-28 2007-03-22 Sirit, Inc. Power control loop and LO generation method
US20070252697A1 (en) * 1998-03-27 2007-11-01 Micron Technology, Inc. Method and system for identifying missing items
US20090036082A1 (en) * 2007-07-31 2009-02-05 Mohammed Sajid Canceling self-jammer and interfering signals in an rfid system
US20090210517A1 (en) * 2002-05-30 2009-08-20 Sony Corporation Information management device and method, information processing device and method recording medium, and program
US7808367B2 (en) 1999-08-09 2010-10-05 Round Rock Research, Llc RFID material tracking method and apparatus
US20110082810A1 (en) * 2008-01-10 2011-04-07 Walt-Task, Llc Human-readable baggage and cargo routing identification system
US8289164B2 (en) 2003-12-12 2012-10-16 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US9171448B1 (en) * 2014-06-11 2015-10-27 Target Brands, Inc. RFID tags for locating products
US20180204030A1 (en) * 2017-01-13 2018-07-19 International Business Machines Corporation Baggage handling
CN108573182A (en) * 2018-04-26 2018-09-25 深圳市盛路物联通讯技术有限公司 A kind of radio frequency signal communication method and system
US20210072375A1 (en) * 2017-05-10 2021-03-11 Google Llc Low-Power Radar

Families Citing this family (190)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6097301A (en) * 1996-04-04 2000-08-01 Micron Communications, Inc. RF identification system with restricted range
US20050040961A1 (en) * 1995-04-11 2005-02-24 Tuttle John R. RF identification system with restricted range
US6804726B1 (en) * 1996-05-22 2004-10-12 Geovector Corporation Method and apparatus for controlling electrical devices in response to sensed conditions
US6369709B1 (en) 1998-04-10 2002-04-09 3M Innovative Properties Company Terminal for libraries and the like
US6420961B1 (en) 1998-05-14 2002-07-16 Micron Technology, Inc. Wireless communication systems, interfacing devices, communication methods, methods of interfacing with an interrogator, and methods of operating an interrogator
ATE352829T1 (en) * 1998-08-14 2007-02-15 3M Innovative Properties Co APPLICATION FOR RADIO FREQUENCY IDENTIFICATION SYSTEMS
EP1145189B1 (en) * 1998-08-14 2008-05-07 3M Innovative Properties Company Radio frequency identification systems applications
US7283061B1 (en) * 1998-08-28 2007-10-16 Marathon Oil Company Method and system for performing operations and for improving production in wells
US20040239521A1 (en) * 2001-12-21 2004-12-02 Zierolf Joseph A. Method and apparatus for determining position in a pipe
US6513015B2 (en) * 1998-09-25 2003-01-28 Fujitsu Limited System and method for customer recognition using wireless identification and visual data transmission
GB9821046D0 (en) * 1998-09-28 1998-11-18 Whitesmith Howard W Detection system
US6360208B1 (en) * 1999-02-04 2002-03-19 Intermec Ip Corp. Method and apparatus for automatic tax verification
US6286762B1 (en) * 1999-09-21 2001-09-11 Intermec Ip Corp. Method and apparatus to perform a predefined search on data carriers, such as RFID tags
US6318636B1 (en) * 1999-09-21 2001-11-20 Intermec Ip Corp. Method and apparatus to read different types of data carriers, such RFID tags and machine-readable symbols, and a user interface for the same
US6286763B1 (en) * 1999-09-21 2001-09-11 Intermac Ip Corp. Method and apparatus to automatically search data carriers, such as RFID tags and machine-readable symbols
US6714133B2 (en) * 1999-12-15 2004-03-30 Koninklijke Philips Electronics N.V. Short range communication system
US6650254B1 (en) 2000-03-13 2003-11-18 Ergodex Computer input device with individually positionable and programmable switches
US6943665B2 (en) 2000-03-21 2005-09-13 T. Eric Chornenky Human machine interface
US20030098774A1 (en) * 2000-03-21 2003-05-29 Chornenky Todd E. Security apparatus
AU2001250044A1 (en) * 2000-03-21 2001-10-03 T. Eric CHORNENKY Security apparatus
US7064669B2 (en) * 2000-06-09 2006-06-20 Light Elliott D Electronic tether for portable objects
GB0015147D0 (en) * 2000-06-21 2000-08-09 Jacobs Michael Tracking system
US20020044058A1 (en) * 2000-08-17 2002-04-18 Heinrich Harley Kent Wrist mounted RFID reader and/or antenna
US6552661B1 (en) * 2000-08-25 2003-04-22 Rf Code, Inc. Zone based radio frequency identification
US6883710B2 (en) * 2000-10-11 2005-04-26 Amerasia International Technology, Inc. Article tracking system and method
EP1514247B1 (en) * 2000-10-16 2013-01-16 Amerasia International Technology, Inc. Article tracking system and method
US6789729B1 (en) * 2000-11-02 2004-09-14 Ford Motor Company Method for receiving and shipping items
WO2002047014A1 (en) * 2000-12-07 2002-06-13 Sap Aktiengesellschaft System, method, computer program product for communicating data for objects that are transported
US6600418B2 (en) 2000-12-12 2003-07-29 3M Innovative Properties Company Object tracking and management system and method using radio-frequency identification tags
EP1220163A1 (en) * 2000-12-29 2002-07-03 EM Microelectronic-Marin SA Passage detection system for individuals or objects through an entrance-exit with a limited space
FR2820518B1 (en) 2001-02-02 2003-04-25 Siemens Automotive Sa METHOD FOR MONITORING THE CONDITION OF A SECURITY BODY
US6774811B2 (en) 2001-02-02 2004-08-10 International Business Machines Corporation Designation and opportunistic tracking of valuables
ATE411577T1 (en) * 2001-03-08 2008-10-15 Em Microelectronic Marin Sa SYSTEM FOR DETECTING THE PASSAGE OF PERSONS OR OBJECTS THROUGH A SPATIAL ENTRANCE-EXIT
US6811903B2 (en) * 2001-04-06 2004-11-02 Evlonyx, Inc. Electrochemical cell recharging system
US6779246B2 (en) 2001-04-23 2004-08-24 Appleton Papers Inc. Method and system for forming RF reflective pathways
US6892441B2 (en) * 2001-04-23 2005-05-17 Appleton Papers Inc. Method for forming electrically conductive pathways
US7014100B2 (en) * 2001-04-27 2006-03-21 Marathon Oil Company Process and assembly for identifying and tracking assets
US7248933B2 (en) * 2001-05-08 2007-07-24 Hill-Rom Services, Inc. Article locating and tracking system
US7242306B2 (en) * 2001-05-08 2007-07-10 Hill-Rom Services, Inc. Article locating and tracking apparatus and method
US7376234B1 (en) 2001-05-14 2008-05-20 Hand Held Products, Inc. Portable keying device and method
US6942155B1 (en) * 2001-05-31 2005-09-13 Alien Technology Corporation Integrated circuits with persistent data storage
US7377445B1 (en) 2001-05-31 2008-05-27 Alien Technology Corporation Integrated circuits with persistent data storage
US7030760B1 (en) 2001-08-07 2006-04-18 Seecontrol, Inc. Method and apparatus for ensuring reliable loading of materials on aricraft and other vehicles
US7635087B1 (en) 2001-10-01 2009-12-22 Avante International Technology, Inc. Method for processing a machine readable ballot and ballot therefor
US7828215B2 (en) * 2001-10-01 2010-11-09 Avante International Technology, Inc. Reader for an optically readable ballot
US7077313B2 (en) 2001-10-01 2006-07-18 Avante International Technology, Inc. Electronic voting method for optically scanned ballot
EP1308864A1 (en) * 2001-11-02 2003-05-07 Hewlett-Packard Company Passenger management system and method and electronic device
US6669089B2 (en) 2001-11-12 2003-12-30 3M Innovative Properties Co Radio frequency identification systems for asset tracking
US7374096B2 (en) 2001-11-21 2008-05-20 Goliath Solutions, Llc Advertising compliance monitoring system
US6951305B2 (en) * 2001-11-21 2005-10-04 Goliath Solutions, Llc. Advertising compliance monitoring system
US6837427B2 (en) * 2001-11-21 2005-01-04 Goliath Solutions, Llc. Advertising compliance monitoring system
FR2834398B1 (en) * 2001-12-27 2005-06-03 Siemens Vdo Automotive METHOD FOR TRANSMITTING A REQUEST TO A BADGE
SE523990C2 (en) * 2001-12-28 2004-06-15 Abb Ab Procedures and systems in an industrially automated facility to send relevant plant information to mobile devices depending on their location
US7406439B2 (en) * 2002-01-31 2008-07-29 International Business Machines Corporation Inventory controls with radio frequency identification
JP3497499B2 (en) * 2002-03-14 2004-02-16 三菱電機株式会社 3D graphic drawing device
JP2006508412A (en) * 2002-03-18 2006-03-09 イル・ガット・インコーポレーテッド System and method for monitoring and tracking individuals
US20040111359A1 (en) * 2002-06-04 2004-06-10 Hudock John J. Business method for credit verification and correction
US6933849B2 (en) 2002-07-09 2005-08-23 Fred Sawyer Method and apparatus for tracking objects and people
US7080779B2 (en) * 2002-07-26 2006-07-25 Automark Technical Systems, Llc Ballot marking system and apparatus
CA2397501A1 (en) * 2002-08-19 2004-02-19 Emerson Nerat Wireless smart system for tracking luggage
US7002472B2 (en) * 2002-09-04 2006-02-21 Northrop Grumman Corporation Smart and secure container
US6903662B2 (en) * 2002-09-19 2005-06-07 Ergodex Computer input device with individually positionable and programmable input members
AU2003275297A1 (en) * 2002-09-27 2004-04-23 Hill-Rom Services, Inc. Universal communications, monitoring, tracking, and control system for a healthcare facility
US6987948B2 (en) * 2002-10-03 2006-01-17 Wildseed Ltd. Identification based operational modification of a portable electronic device
US7431436B1 (en) 2002-11-12 2008-10-07 Vutek, Incorporated Identification system for inks in printing systems
GB2395592B (en) * 2002-11-21 2006-05-17 Hewlett Packard Co Method of annotating an item with electronic data and apparatus therefor
US7636568B2 (en) * 2002-12-02 2009-12-22 The Boeing Company Remote aircraft manufacturing, monitoring, maintenance and management system
GB2396004B (en) * 2002-12-06 2006-02-22 Optex Co Ltd Anti-thief security sensor assembly with variable amount of emitted infrared beam
GB0230360D0 (en) * 2002-12-27 2003-02-05 Koninkl Philips Electronics Nv Object identifying method and apparatus
US7314172B2 (en) * 2003-01-17 2008-01-01 Automark Technical Systems, Llc Ballot marking system and apparatus having periodic ballot alignment compensation
US20040186768A1 (en) * 2003-03-21 2004-09-23 Peter Wakim Apparatus and method for initiating remote content delivery by local user identification
US7538745B2 (en) * 2003-03-24 2009-05-26 Ntag Interactive Corporation Apparatus and method for enhancing face-to-face communication
EP1625525A4 (en) * 2003-03-24 2010-01-27 Ntag Interactive Corp Apparatus and method for enhancing face-to-face communication
US6970092B2 (en) * 2003-04-15 2005-11-29 Koninklijke Philips Electronics,N.V. Short range communication system
US8063885B2 (en) * 2003-06-04 2011-11-22 Es&S Automark, Llc Ballot marking system and apparatus utilizing pivotal touchscreen
WO2004109583A1 (en) * 2003-06-06 2004-12-16 Stemco Llc Wireless communication device, system for communication and communication method
JP4624361B2 (en) * 2003-10-29 2011-02-02 エヌエックスピー ビー ヴィ Communication partner device with automatic transmission mode activation
US20050094825A1 (en) * 2003-10-30 2005-05-05 Loness Gene A. Remotely controlled sound generator
US7290287B2 (en) * 2003-11-20 2007-10-30 International Business Machines Corporation Security screening of electronic devices by device identifier
US8085132B2 (en) * 2003-12-10 2011-12-27 Barry Allen Method and apparatus for resolving RFID-based object traffic transactions to a single object in the presence of a plurality of objects
US7345576B2 (en) * 2003-12-10 2008-03-18 Identec Solutions Inc. Method and apparatus for resolving RFID-based object traffic transactions to a single container in the presence of a plurality of containers
US8061600B2 (en) * 2003-12-18 2011-11-22 Altierre Corporation Wireless display tag
JP4726037B2 (en) * 2004-01-20 2011-07-20 オムロンオートモーティブエレクトロニクス株式会社 Transponder start control method and tire condition monitoring system interrogator
US20050280508A1 (en) * 2004-02-24 2005-12-22 Jim Mravca System and method for controlling range of successful interrogation by RFID interrogation device
US20050184150A1 (en) * 2004-02-24 2005-08-25 Welte Gregory A. Device to prevent credit card loss
US7574608B2 (en) * 2004-03-04 2009-08-11 International Business Machines Corporation Security screening of electronic devices by device-reported data
US7030761B2 (en) * 2004-03-16 2006-04-18 Symbol Technologies Multi-resolution object location system and method
JP2005309844A (en) * 2004-04-22 2005-11-04 Ntt Docomo Inc Management system and management method
US7003374B2 (en) * 2004-04-28 2006-02-21 Goodrich Corporation Aircraft cargo loading logistics system using machine readable identifiers
US7100827B2 (en) * 2004-04-28 2006-09-05 Goodrich Corporation Aircraft cargo loading logistics system
US7198227B2 (en) * 2004-06-10 2007-04-03 Goodrich Corporation Aircraft cargo locating system
WO2005124669A2 (en) * 2004-06-15 2005-12-29 Koninklijke Philips Electronics N.V. Radio identification with an additional close-range check
US20060007000A1 (en) * 2004-07-07 2006-01-12 Rosita Yap File indexing and retrieval system employing RFID visual indicators
US7403120B2 (en) * 2004-09-29 2008-07-22 Symbol Technologies, Inc. Reverse infrastructure location system and method
US7195159B2 (en) * 2004-10-22 2007-03-27 Symbol Technologies, Inc. Radio frequency identification (RFID) material tracking and apparatus
US7243476B2 (en) * 2004-12-03 2007-07-17 Checkpoint Systems, Inc. Method and system for tracking items in a shipping facility
US20060152364A1 (en) * 2004-12-30 2006-07-13 Walton Charles A RFID with field changeable identification
US7446644B2 (en) * 2005-01-14 2008-11-04 Secureall Corporation Universal hands free key and lock system
US7429984B2 (en) * 2005-02-04 2008-09-30 Philip Morris Usa Inc. Display management system
US8624740B2 (en) * 2005-02-04 2014-01-07 Philip Morris Usa Inc. Controllable RFID card
US20060178110A1 (en) * 2005-02-09 2006-08-10 Nokia Corporation System and method for interacting with an entity by means of a mobile station via a user-wearable terminal
US20060195354A1 (en) * 2005-02-28 2006-08-31 Ntag Interactive Corporation Method of scoring the performance of attendees at a meeting
WO2006093992A2 (en) * 2005-03-01 2006-09-08 I.D. Systems, Inc. Mobile portal for rfid applications
US7242303B2 (en) * 2005-03-04 2007-07-10 Cisco Technology, Inc. Navigation and coordination during emergencies
JP4806954B2 (en) * 2005-04-15 2011-11-02 オムロン株式会社 Information processing apparatus, information processing apparatus control method, information processing apparatus control program, and recording medium on which information processing apparatus control program is recorded
US7330120B2 (en) * 2005-04-29 2008-02-12 Hewlett-Packard Development Company, L.P. Remote measurement of motion employing RFID
US7298272B2 (en) * 2005-04-29 2007-11-20 Hewlett-Packard Development Company, L.P. Remote detection employing RFID
US7330119B2 (en) * 2005-04-29 2008-02-12 Hewlett-Packard Development Company, L.P. Remote measurement employing RFID
JP2006319710A (en) * 2005-05-13 2006-11-24 Brother Ind Ltd Wireless tag communication system
US7271718B2 (en) * 2005-05-31 2007-09-18 Lucent Technologies Inc. Protection against loss or theft of identification badges and other items
US7538670B2 (en) * 2005-06-20 2009-05-26 Sun Microsystems, Inc. Method for detecting objects separated from a group
US7336153B2 (en) * 2005-06-30 2008-02-26 Hewlett-Packard Development Company, L.P. Wireless temperature monitoring for an electronics system
US7607014B2 (en) * 2005-06-30 2009-10-20 Hewlett-Packard Development Company, L.P. Authenticating maintenance access to an electronics unit via wireless communication
US7400252B2 (en) * 2005-06-30 2008-07-15 Hewlett-Packard Development Company, L.P. Wireless monitoring of component compatibility in an electronics system
US7737847B2 (en) * 2005-06-30 2010-06-15 Hewlett-Packard Development Company, L.P. Wireless monitoring for an electronics system
EP1910964A1 (en) * 2005-07-29 2008-04-16 Alcon, Inc. Method and system for configuring and data populating a surgical device
US8587430B2 (en) * 2005-09-20 2013-11-19 Lyngsoe Systems, Ltd. Active logistical tag for cargo
US8199689B2 (en) 2005-09-21 2012-06-12 Intermec Ip Corp. Stochastic communication protocol method and system for radio frequency identification (RFID) tags based on coalition formation, such as for tag-to-tag communication
FR2891933B1 (en) * 2005-10-07 2008-12-26 Patrick Simonnet NOMAD DISPATCH OF DIFFUSION OF MULTIMEDIA CONTENT
DE102005049740A1 (en) * 2005-10-14 2007-04-19 ASTRA Gesellschaft für Asset Management mbH & Co. KG Installation for monitoring the manual transfer of goods bearing identification carriers
US7705733B2 (en) * 2006-01-06 2010-04-27 Warsaw Orthopedic, Inc. Coiled RFID tag
US20070198324A1 (en) * 2006-02-22 2007-08-23 Borovoy Richard D Enabling connections between and events attended by people
US8063746B2 (en) * 2006-03-31 2011-11-22 Assa Abloy Ab Transponder detector for an RFID system generating a progression of detection signals
US20070236334A1 (en) * 2006-03-31 2007-10-11 Borovoy Richard D Enhancing face-to-face communication
US8120461B2 (en) 2006-04-03 2012-02-21 Intermec Ip Corp. Automatic data collection device, method and article
US20070273481A1 (en) * 2006-05-25 2007-11-29 Symbol Technologies, Inc. RFID tag with programmable read range
US7940169B2 (en) * 2006-06-15 2011-05-10 General Electric Company System and method for installed base data maintenance
US20070289164A1 (en) * 2006-06-16 2007-12-20 Future Chem International Co., Ltd Footwear having novel shoe upper
WO2007148287A2 (en) * 2006-06-19 2007-12-27 Visible Assets, Inc. Long wave wireless pair-wise linkage using an embedded visibility network
US20070295817A1 (en) * 2006-06-22 2007-12-27 Intermec Ip Corp. Automatic data collection apparatus and method for variable focus using a deformable mirror
EP1873682A3 (en) * 2006-06-30 2008-10-22 Siemens Aktiengesellschaft System and method for obtaining information from objects provided with bar codes and RFID tags
US8002173B2 (en) 2006-07-11 2011-08-23 Intermec Ip Corp. Automatic data collection device, method and article
WO2008009023A2 (en) * 2006-07-14 2008-01-17 Emerson Electric Co. Rfid detection system for enhanced marketing
US20080042803A1 (en) * 2006-07-27 2008-02-21 Joshua Posamentier Adjusting signal strength used to detect tags
US8061617B2 (en) * 2006-07-28 2011-11-22 Intermec Ip Corp. Enhanced resolution automatic data collection apparatus and method using an afocal optical element
US20080030341A1 (en) * 2006-08-02 2008-02-07 Taiwan Semiconductor Manufacturing Co., Ltd. Electronic rack and material management systems utilizing the same
US7310070B1 (en) 2006-08-23 2007-12-18 Goliath Solutions, Llc Radio frequency identification shelf antenna with a distributed pattern for localized tag detection
JP2008085784A (en) * 2006-09-28 2008-04-10 Olympus Corp Mobile device system and mobile device
US8199004B1 (en) * 2006-09-29 2012-06-12 Ncr Corporation RFID tag reader
US8049616B2 (en) * 2006-11-30 2011-11-01 Patricia Hill Method and apparatus for destination tracking with misrouting indication
US8994533B2 (en) * 2006-11-30 2015-03-31 Patent Navigation, Inc. Conditional RFID
WO2008084353A1 (en) * 2007-01-08 2008-07-17 Nxp B.V. Transponders and methods for operating a transponder
US7546955B2 (en) * 2007-03-16 2009-06-16 Intermec Ip Corp. Systems, devices, and methods for reading machine-readable characters and human-readable characters
US7859416B2 (en) * 2007-06-21 2010-12-28 Round Rock Research, Llc Method and system of attaching a RFID tag to an object
US7916025B2 (en) * 2007-08-10 2011-03-29 Lockwinn Technology Intelligent luggage tag
EP2051100A1 (en) * 2007-10-19 2009-04-22 Ford Global Technologies, LLC A method and system for presence detection
JP5152704B2 (en) * 2008-01-08 2013-02-27 オムロン株式会社 Tag communication device, tag communication system, and tag communication method
US9194227B2 (en) 2008-03-07 2015-11-24 Marathon Oil Company Systems, assemblies and processes for controlling tools in a wellbore
US10119377B2 (en) * 2008-03-07 2018-11-06 Weatherford Technology Holdings, Llc Systems, assemblies and processes for controlling tools in a well bore
WO2009122558A1 (en) * 2008-03-31 2009-10-08 Iwase Ikuro Goods manufacturing method, goods manufacturing system, and goods
ES2396015T3 (en) * 2008-04-01 2013-02-18 Assa Abloy Ab Switching capacity method for detecting a wireless transponder device using a single antenna and successive communication with it
US8717144B2 (en) * 2008-04-29 2014-05-06 Intelleflex Corporation RFID system with distributed readers
US8066184B2 (en) 2008-04-30 2011-11-29 Avante International Technology, Inc. Optically readable marking sheet and reading apparatus and method therefor
US10447334B2 (en) 2008-07-09 2019-10-15 Secureall Corporation Methods and systems for comprehensive security-lockdown
US10128893B2 (en) 2008-07-09 2018-11-13 Secureall Corporation Method and system for planar, multi-function, multi-power sourced, long battery life radio communication appliance
US9642089B2 (en) 2008-07-09 2017-05-02 Secureall Corporation Method and system for planar, multi-function, multi-power sourced, long battery life radio communication appliance
US11469789B2 (en) 2008-07-09 2022-10-11 Secureall Corporation Methods and systems for comprehensive security-lockdown
TWI384248B (en) * 2008-09-26 2013-02-01 Mstar Semiconductor Inc Item positioning system and method thereof
JP5282785B2 (en) * 2008-10-15 2013-09-04 富士通株式会社 Luggage arrangement management method, transport device, and transport control program
US8644511B2 (en) 2008-11-05 2014-02-04 Comcast Cable Communications, LLC. System and method for providing digital content
US8386261B2 (en) * 2008-11-14 2013-02-26 Vocollect Healthcare Systems, Inc. Training/coaching system for a voice-enabled work environment
US8261985B2 (en) 2009-04-07 2012-09-11 Avante Corporation Limited Manual recount process using digitally imaged ballots
US8356874B2 (en) 2009-04-08 2013-01-22 Redwood Technologies, Llc Apparatus and method for precision application and metering of a two-part (binary) imaging solution in an ink jet printer
US8960880B2 (en) 2009-04-08 2015-02-24 Redwood Technologies, Llc Binary epoxy ink and enhanced printer systems, structures, and associated methods
US8144015B2 (en) * 2009-09-23 2012-03-27 Microsoft Corporation Power efficient object detection with selective polling
US8261986B2 (en) 2009-10-21 2012-09-11 Kevin Kwong-Tai Chung System and method for decoding an optically readable markable sheet and markable sheet therefor
US8850899B2 (en) 2010-04-15 2014-10-07 Marathon Oil Company Production logging processes and systems
US8963720B2 (en) 2010-05-11 2015-02-24 The Boeing Company RFID tag container
US8659397B2 (en) 2010-07-22 2014-02-25 Vocollect, Inc. Method and system for correctly identifying specific RFID tags
US9162776B2 (en) 2010-08-18 2015-10-20 The Boeing Company Aircraft safety and configuration monitoring system and method
USD643400S1 (en) 2010-08-19 2011-08-16 Vocollect Healthcare Systems, Inc. Body-worn mobile device
USD643013S1 (en) 2010-08-20 2011-08-09 Vocollect Healthcare Systems, Inc. Body-worn mobile device
US9609281B2 (en) 2010-09-29 2017-03-28 International Business Machines Corporation Validating asset movement using virtual tripwires and a RFID-enabled asset management system
US8823554B2 (en) 2010-12-09 2014-09-02 The Boeing Company Managing a plurality of radio frequency identification devices
US8791823B2 (en) 2011-06-03 2014-07-29 The Boeing Company Aircraft part control system
WO2013170009A1 (en) 2012-05-09 2013-11-14 Applied Dna Sciences, Inc. Verification of physical encryption taggants uning digital representatives and authentications thereof
US9830424B2 (en) 2013-09-18 2017-11-28 Hill-Rom Services, Inc. Bed/room/patient association systems and methods
US9392411B1 (en) 2014-04-08 2016-07-12 Ahmed Khalifa Al-Yousif Item and object location system
US20170352256A1 (en) * 2014-12-22 2017-12-07 Technomirai Co., Ltd. Digital find security system, method, and program
US10289882B2 (en) * 2016-06-23 2019-05-14 Amadeus S.A.S. Cargo handling system
US10127747B2 (en) 2016-12-22 2018-11-13 Active8 Software, LLC Systems and methods for electronic ticketing, monitoring, and indicating permissive use of facilities
CN110520337B (en) 2017-01-05 2022-08-30 复兴者迈科思公司 Digital license plate system with anti-theft system
JP7145159B2 (en) 2017-01-05 2022-09-30 リバイバーエムエックス,インク. Power and communication modes for digital license plates
EP3984828A1 (en) 2017-01-05 2022-04-20 Revivermx, Inc. Thermal control system for a digital license plate
KR101808589B1 (en) * 2017-04-10 2017-12-13 한미아이티 주식회사 System for managing items using tag information
US11911325B2 (en) 2019-02-26 2024-02-27 Hill-Rom Services, Inc. Bed interface for manual location
CN114844531A (en) 2019-04-11 2022-08-02 奈克赛特公司 System for simultaneous tag triggering and sequential tag reading
US11551537B2 (en) * 2019-04-11 2023-01-10 Nexite Ltd. Wireless dual-mode identification tag
EP4275160A1 (en) 2021-01-11 2023-11-15 Nexite Ltd. Contactless and automatic operations of a retail store
US20230186329A1 (en) 2021-12-13 2023-06-15 Nexite Ltd. Systems and methods for estimating foot traffic

Citations (91)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3679874A (en) * 1970-07-06 1972-07-25 Bendix Corp Automatic baggage handling system
US3689885A (en) * 1970-09-15 1972-09-05 Transitag Corp Inductively coupled passive responder and interrogator unit having multidimension electromagnetic field capabilities
US3832530A (en) * 1972-01-04 1974-08-27 Westinghouse Electric Corp Object identifying apparatus
US3986119A (en) * 1973-12-28 1976-10-12 International Business Machines Corporation Emergency communication system
US4075632A (en) * 1974-08-27 1978-02-21 The United States Of America As Represented By The United States Department Of Energy Interrogation, and detection system
US4354189A (en) * 1977-11-09 1982-10-12 Lemelson Jerome H Switch and lock activating system and method
US4684933A (en) * 1986-05-15 1987-08-04 Rita Ann Gray Unauthorized personnel detection system
US4750197A (en) * 1986-11-10 1988-06-07 Denekamp Mark L Integrated cargo security system
US4761778A (en) * 1985-04-11 1988-08-02 Massachusetts Institute Of Technology Coder-packetizer for random accessing in digital communication with multiple accessing
US4766299A (en) * 1986-03-28 1988-08-23 Spectra-Physics, Inc. Hand-mounted bar code reader
US4776464A (en) * 1985-06-17 1988-10-11 Bae Automated Systems, Inc. Automated article handling system and process
US4799059A (en) * 1986-03-14 1989-01-17 Enscan, Inc. Automatic/remote RF instrument monitoring system
US4811421A (en) * 1986-03-14 1989-03-07 Christophe Havel Transmission power control device in a radio communication transmitting/receiving station
US4837575A (en) * 1985-11-04 1989-06-06 Motorola, Inc. Identification system
US4845504A (en) * 1987-04-08 1989-07-04 M/A-Com, Inc. Mobile radio network for nationwide communications
US4850009A (en) * 1986-05-12 1989-07-18 Clinicom Incorporated Portable handheld terminal including optical bar code reader and electromagnetic transceiver means for interactive wireless communication with a base communications station
US4857893A (en) * 1986-07-18 1989-08-15 Bi Inc. Single chip transponder device
US4862160A (en) * 1983-12-29 1989-08-29 Revlon, Inc. Item identification tag for rapid inventory data acquisition system
US4955018A (en) * 1987-11-10 1990-09-04 Echelon Systems Corporation Protocol for network having plurality of intelligent cells
US4969146A (en) * 1987-11-10 1990-11-06 Echelon Systems Corporation Protocol for network having a plurality of intelligent cells
US4999636A (en) * 1989-02-17 1991-03-12 Amtech Technology Corporation Range limiting system
US5003619A (en) * 1989-01-31 1991-03-26 Motorola, Inc. Method and apparatus for adjusting the power of a transmitter
US5008661A (en) * 1985-09-27 1991-04-16 Raj Phani K Electronic remote chemical identification system
US5019813A (en) * 1987-04-13 1991-05-28 N.V. Nederlandsche Apparatenfabriek Nedap System for the contactless exchange of data
US5025486A (en) * 1988-12-09 1991-06-18 Dallas Semiconductor Corporation Wireless communication system with parallel polling
US5030807A (en) * 1990-01-16 1991-07-09 Amtech Corporation System for reading and writing data from and into remote tags
US5046066A (en) * 1987-02-09 1991-09-03 Telesystems Slw Inc. Wireless local area network
US5055968A (en) * 1988-07-04 1991-10-08 Sony Corporation Thin electronic device having an integrated circuit chip and a power battery and a method for producing same
US5055659A (en) * 1990-02-06 1991-10-08 Amtech Technology Corp. High speed system for reading and writing data from and into remote tags
US5121407A (en) * 1990-09-27 1992-06-09 Pittway Corporation Spread spectrum communications system
US5124697A (en) * 1989-10-16 1992-06-23 Motorola, Inc. Acknowledge-back pager
US5144313A (en) * 1988-10-27 1992-09-01 Steffen Kirknes Method for processing transmitted and reflected signals for removing unwanted signals and noise from wanted signals
US5144668A (en) * 1991-01-25 1992-09-01 Motorola, Inc. Signal overlap detection in a communication system
US5144314A (en) * 1987-10-23 1992-09-01 Allen-Bradley Company, Inc. Programmable object identification transponder system
US5150310A (en) * 1989-08-30 1992-09-22 Consolve, Inc. Method and apparatus for position detection
US5150114A (en) * 1989-11-10 1992-09-22 U.S. Philips Corporation Polling-type information transmission system
US5148618A (en) * 1990-06-01 1992-09-22 Brewster Blair M Sealed tag
US5164985A (en) * 1987-10-27 1992-11-17 Nysen Paul A Passive universal communicator system
US5168510A (en) * 1984-03-06 1992-12-01 Comsource Systems Spread spectrum-time diversity communications systems and transceivers for multidrop area networks
US5194860A (en) * 1989-11-16 1993-03-16 The General Electric Company, P.L.C. Radio telemetry systems with channel selection
US5214410A (en) * 1989-07-10 1993-05-25 Csir Location of objects
US5220678A (en) * 1991-08-12 1993-06-15 Motorola, Inc. Method and apparatus for adjusting the power of a transmitter
US5231646A (en) * 1992-03-16 1993-07-27 Kyros Corporation Communications system
US5245346A (en) * 1989-12-28 1993-09-14 Kabushiki Kaisha Toyota Chuo Kenyusho Interrogator/transponder system and mobile transponder device
US5272324A (en) * 1990-08-10 1993-12-21 Interlink Technologies, Inc. Portable scanner system with transceiver for two-way radio frequency communication
US5278992A (en) * 1991-11-08 1994-01-11 Teknekron Communications Systems, Inc. Method and apparatus for controlling transmission power of a remote unit communicating with a base unit over a common frequency channel
US5307463A (en) * 1990-03-08 1994-04-26 Allen-Bradley Company, Inc. Programmable controller communication module
US5313211A (en) * 1990-08-13 1994-05-17 Sharp Kabushiki Kaisha Portable data processing device capable of transmitting processed data on a radio by reflection of unmodulated carrier signal externally applied
US5326652A (en) * 1993-01-25 1994-07-05 Micron Semiconductor, Inc. Battery package and method using flexible polymer films having a deposited layer of an inorganic material
US5340968A (en) * 1991-05-07 1994-08-23 Nippondenso Company, Ltd. Information storage medium with electronic and visual areas
US5347274A (en) * 1990-05-17 1994-09-13 At/Comm Incorporated Hazardous waste transport management system
US5365551A (en) * 1992-12-15 1994-11-15 Micron Technology, Inc. Data communication transceiver using identification protocol
US5373503A (en) * 1993-04-30 1994-12-13 Information Technology, Inc. Group randomly addressed polling method
US5382784A (en) * 1993-02-08 1995-01-17 Indala Corporation Hand-held dual technology identification tag reading head
US5406263A (en) * 1992-07-27 1995-04-11 Micron Communications, Inc. Anti-theft method for detecting the unauthorized opening of containers and baggage
US5416310A (en) * 1993-05-28 1995-05-16 Symbol Technologies, Inc. Computer and/or scanner system incorporated into a garment
US5448110A (en) * 1992-06-17 1995-09-05 Micron Communications, Inc. Enclosed transceiver
US5497140A (en) * 1992-08-12 1996-03-05 Micron Technology, Inc. Electrically powered postage stamp or mailing or shipping label operative with radio frequency (RF) communication
US5500650A (en) * 1992-12-15 1996-03-19 Micron Technology, Inc. Data communication method using identification protocol
US5500651A (en) * 1994-06-24 1996-03-19 Texas Instruments Incorporated System and method for reading multiple RF-ID transponders
US5521600A (en) * 1994-09-06 1996-05-28 The Regents Of The University Of California Range-gated field disturbance sensor with range-sensitivity compensation
US5534847A (en) * 1994-11-23 1996-07-09 Mcgregor; Gerald C. Bicycle alarm system
US5560970A (en) * 1993-07-16 1996-10-01 Esselte Meto International Gmbh Display marking tag, such as a display marking tag having an adhesive fastening strip
USH1606H (en) * 1994-07-22 1996-11-05 The United States Of America As Represented By The Secretary Of The Army Electronic quasi-passive identification system
US5602535A (en) * 1994-07-15 1997-02-11 The Friedkin Corporation Vehicle security system based on two step communication range between transmitter and receiver
US5610387A (en) * 1992-05-15 1997-03-11 Symbol Technologies, Inc. Portable optical scanning system worn by a user for reading indicia of differing light reflectivity
US5613228A (en) * 1992-07-06 1997-03-18 Micron Technology, Inc. Gain adjustment method in two-way communication systems
US5627517A (en) * 1995-11-01 1997-05-06 Xerox Corporation Decentralized tracking and routing system wherein packages are associated with active tags
US5640002A (en) * 1995-08-15 1997-06-17 Ruppert; Jonathan Paul Portable RF ID tag and barcode reader
US5671362A (en) * 1995-04-04 1997-09-23 Cowe; Alan B. Materials monitoring systems, materials management systems and related methods
US5751227A (en) * 1994-12-22 1998-05-12 Nippondenso Co., Ltd. Communication system for vehicles
US5751256A (en) * 1994-03-04 1998-05-12 Flexcon Company Inc. Resonant tag labels and method of making same
US5785181A (en) * 1995-11-02 1998-07-28 Clothestrak, Inc. Permanent RFID garment tracking system
US5793305A (en) * 1991-04-03 1998-08-11 Turner; Leigh Holbrook Article sorting system
US5798693A (en) * 1995-06-07 1998-08-25 Engellenner; Thomas J. Electronic locating systems
US5828693A (en) * 1996-03-21 1998-10-27 Amtech Corporation Spread spectrum frequency hopping reader system
US5850187A (en) * 1996-03-27 1998-12-15 Amtech Corporation Integrated electronic tag reader and wireless communication link
US5855988A (en) * 1995-11-27 1999-01-05 Nippon Paint Co., Ltd. Electromagnetic wave absorbing shielding material
US5887176A (en) * 1996-06-28 1999-03-23 Randtec, Inc. Method and system for remote monitoring and tracking of inventory
US5920287A (en) * 1997-01-21 1999-07-06 Widata Corporation Radio location system for precisely tracking objects by RF transceiver tags which randomly and repetitively emit wideband identification signals
US5963927A (en) * 1996-01-31 1999-10-05 Neopost Limited Mailing system
US5971587A (en) * 1997-08-01 1999-10-26 Kato; Kiroku Package and mail delivery system
US6097301A (en) * 1996-04-04 2000-08-01 Micron Communications, Inc. RF identification system with restricted range
US6121544A (en) * 1998-01-15 2000-09-19 Petsinger; Julie Ann Electromagnetic shield to prevent surreptitious access to contactless smartcards
US6144301A (en) * 1997-02-10 2000-11-07 Safetrac Control Systems, Inc. Electronic tracking tag
US6538564B1 (en) * 1997-01-17 2003-03-25 Integrated Silicon Design Pty Ltd Multiple tag reading system
US20060187061A1 (en) * 2005-02-07 2006-08-24 Colby Steven M Radio frequency shielding
US7163152B2 (en) * 2004-12-15 2007-01-16 Osborn Warren R Protective container for readable cards
US7175084B2 (en) * 2000-05-03 2007-02-13 Axalto Sa Integrated circuit card and case therefor
US20070040653A1 (en) * 2005-08-16 2007-02-22 Potts Kevin L Rfid shielding devices
US7482925B2 (en) * 2005-06-24 2009-01-27 Visa U.S.A. Apparatus and method to electromagnetically shield portable consumer devices

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5565858A (en) * 1994-09-14 1996-10-15 Northrop Grumman Corporation Electronic inventory system for stacked containers
US5742237A (en) * 1995-11-30 1998-04-21 Lockheed Martin Corporation Tag location monitor
US5842555A (en) * 1996-12-16 1998-12-01 Gannon; Donald N. Automated baggage tracking system and method for use in a baggage conveyor system

Patent Citations (95)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3679874A (en) * 1970-07-06 1972-07-25 Bendix Corp Automatic baggage handling system
US3689885A (en) * 1970-09-15 1972-09-05 Transitag Corp Inductively coupled passive responder and interrogator unit having multidimension electromagnetic field capabilities
US3832530A (en) * 1972-01-04 1974-08-27 Westinghouse Electric Corp Object identifying apparatus
US3986119A (en) * 1973-12-28 1976-10-12 International Business Machines Corporation Emergency communication system
US4075632A (en) * 1974-08-27 1978-02-21 The United States Of America As Represented By The United States Department Of Energy Interrogation, and detection system
US4354189A (en) * 1977-11-09 1982-10-12 Lemelson Jerome H Switch and lock activating system and method
US4862160A (en) * 1983-12-29 1989-08-29 Revlon, Inc. Item identification tag for rapid inventory data acquisition system
US5168510A (en) * 1984-03-06 1992-12-01 Comsource Systems Spread spectrum-time diversity communications systems and transceivers for multidrop area networks
US4761778A (en) * 1985-04-11 1988-08-02 Massachusetts Institute Of Technology Coder-packetizer for random accessing in digital communication with multiple accessing
US4776464A (en) * 1985-06-17 1988-10-11 Bae Automated Systems, Inc. Automated article handling system and process
US5008661A (en) * 1985-09-27 1991-04-16 Raj Phani K Electronic remote chemical identification system
US4837575A (en) * 1985-11-04 1989-06-06 Motorola, Inc. Identification system
US4799059A (en) * 1986-03-14 1989-01-17 Enscan, Inc. Automatic/remote RF instrument monitoring system
US4811421A (en) * 1986-03-14 1989-03-07 Christophe Havel Transmission power control device in a radio communication transmitting/receiving station
US4766299A (en) * 1986-03-28 1988-08-23 Spectra-Physics, Inc. Hand-mounted bar code reader
US4850009A (en) * 1986-05-12 1989-07-18 Clinicom Incorporated Portable handheld terminal including optical bar code reader and electromagnetic transceiver means for interactive wireless communication with a base communications station
US4684933A (en) * 1986-05-15 1987-08-04 Rita Ann Gray Unauthorized personnel detection system
US4857893A (en) * 1986-07-18 1989-08-15 Bi Inc. Single chip transponder device
US4750197A (en) * 1986-11-10 1988-06-07 Denekamp Mark L Integrated cargo security system
US5046066A (en) * 1987-02-09 1991-09-03 Telesystems Slw Inc. Wireless local area network
US4845504A (en) * 1987-04-08 1989-07-04 M/A-Com, Inc. Mobile radio network for nationwide communications
US5019813A (en) * 1987-04-13 1991-05-28 N.V. Nederlandsche Apparatenfabriek Nedap System for the contactless exchange of data
US5144314A (en) * 1987-10-23 1992-09-01 Allen-Bradley Company, Inc. Programmable object identification transponder system
US5164985A (en) * 1987-10-27 1992-11-17 Nysen Paul A Passive universal communicator system
US4969146A (en) * 1987-11-10 1990-11-06 Echelon Systems Corporation Protocol for network having a plurality of intelligent cells
US4955018A (en) * 1987-11-10 1990-09-04 Echelon Systems Corporation Protocol for network having plurality of intelligent cells
US5055968A (en) * 1988-07-04 1991-10-08 Sony Corporation Thin electronic device having an integrated circuit chip and a power battery and a method for producing same
US5144313A (en) * 1988-10-27 1992-09-01 Steffen Kirknes Method for processing transmitted and reflected signals for removing unwanted signals and noise from wanted signals
US5025486A (en) * 1988-12-09 1991-06-18 Dallas Semiconductor Corporation Wireless communication system with parallel polling
US5003619A (en) * 1989-01-31 1991-03-26 Motorola, Inc. Method and apparatus for adjusting the power of a transmitter
US4999636A (en) * 1989-02-17 1991-03-12 Amtech Technology Corporation Range limiting system
US5214410A (en) * 1989-07-10 1993-05-25 Csir Location of objects
US5150310A (en) * 1989-08-30 1992-09-22 Consolve, Inc. Method and apparatus for position detection
US5124697A (en) * 1989-10-16 1992-06-23 Motorola, Inc. Acknowledge-back pager
US5150114A (en) * 1989-11-10 1992-09-22 U.S. Philips Corporation Polling-type information transmission system
US5194860A (en) * 1989-11-16 1993-03-16 The General Electric Company, P.L.C. Radio telemetry systems with channel selection
US5245346A (en) * 1989-12-28 1993-09-14 Kabushiki Kaisha Toyota Chuo Kenyusho Interrogator/transponder system and mobile transponder device
US5030807A (en) * 1990-01-16 1991-07-09 Amtech Corporation System for reading and writing data from and into remote tags
US5055659A (en) * 1990-02-06 1991-10-08 Amtech Technology Corp. High speed system for reading and writing data from and into remote tags
US5307463A (en) * 1990-03-08 1994-04-26 Allen-Bradley Company, Inc. Programmable controller communication module
US5347274A (en) * 1990-05-17 1994-09-13 At/Comm Incorporated Hazardous waste transport management system
US5148618A (en) * 1990-06-01 1992-09-22 Brewster Blair M Sealed tag
US5272324A (en) * 1990-08-10 1993-12-21 Interlink Technologies, Inc. Portable scanner system with transceiver for two-way radio frequency communication
US5313211A (en) * 1990-08-13 1994-05-17 Sharp Kabushiki Kaisha Portable data processing device capable of transmitting processed data on a radio by reflection of unmodulated carrier signal externally applied
US5121407A (en) * 1990-09-27 1992-06-09 Pittway Corporation Spread spectrum communications system
US5144668A (en) * 1991-01-25 1992-09-01 Motorola, Inc. Signal overlap detection in a communication system
US5793305A (en) * 1991-04-03 1998-08-11 Turner; Leigh Holbrook Article sorting system
US5340968A (en) * 1991-05-07 1994-08-23 Nippondenso Company, Ltd. Information storage medium with electronic and visual areas
US5220678A (en) * 1991-08-12 1993-06-15 Motorola, Inc. Method and apparatus for adjusting the power of a transmitter
US5278992A (en) * 1991-11-08 1994-01-11 Teknekron Communications Systems, Inc. Method and apparatus for controlling transmission power of a remote unit communicating with a base unit over a common frequency channel
US5231646A (en) * 1992-03-16 1993-07-27 Kyros Corporation Communications system
US5610387A (en) * 1992-05-15 1997-03-11 Symbol Technologies, Inc. Portable optical scanning system worn by a user for reading indicia of differing light reflectivity
US5448110A (en) * 1992-06-17 1995-09-05 Micron Communications, Inc. Enclosed transceiver
US5613228A (en) * 1992-07-06 1997-03-18 Micron Technology, Inc. Gain adjustment method in two-way communication systems
US5406263A (en) * 1992-07-27 1995-04-11 Micron Communications, Inc. Anti-theft method for detecting the unauthorized opening of containers and baggage
US5497140A (en) * 1992-08-12 1996-03-05 Micron Technology, Inc. Electrically powered postage stamp or mailing or shipping label operative with radio frequency (RF) communication
US5627544A (en) * 1992-12-15 1997-05-06 Micron Technology, Inc. Data communication method using identification protocol
US5583850A (en) * 1992-12-15 1996-12-10 Micron Technology, Inc. Data communication system using identification protocol
US5500650A (en) * 1992-12-15 1996-03-19 Micron Technology, Inc. Data communication method using identification protocol
US5841770A (en) * 1992-12-15 1998-11-24 Micron Technology, Inc. Data communication system using indentification protocol
US5365551A (en) * 1992-12-15 1994-11-15 Micron Technology, Inc. Data communication transceiver using identification protocol
US5326652A (en) * 1993-01-25 1994-07-05 Micron Semiconductor, Inc. Battery package and method using flexible polymer films having a deposited layer of an inorganic material
US5382784A (en) * 1993-02-08 1995-01-17 Indala Corporation Hand-held dual technology identification tag reading head
US5373503A (en) * 1993-04-30 1994-12-13 Information Technology, Inc. Group randomly addressed polling method
US5416310A (en) * 1993-05-28 1995-05-16 Symbol Technologies, Inc. Computer and/or scanner system incorporated into a garment
US5560970A (en) * 1993-07-16 1996-10-01 Esselte Meto International Gmbh Display marking tag, such as a display marking tag having an adhesive fastening strip
US5751256A (en) * 1994-03-04 1998-05-12 Flexcon Company Inc. Resonant tag labels and method of making same
US5500651A (en) * 1994-06-24 1996-03-19 Texas Instruments Incorporated System and method for reading multiple RF-ID transponders
US5602535A (en) * 1994-07-15 1997-02-11 The Friedkin Corporation Vehicle security system based on two step communication range between transmitter and receiver
USH1606H (en) * 1994-07-22 1996-11-05 The United States Of America As Represented By The Secretary Of The Army Electronic quasi-passive identification system
US5521600A (en) * 1994-09-06 1996-05-28 The Regents Of The University Of California Range-gated field disturbance sensor with range-sensitivity compensation
US5534847A (en) * 1994-11-23 1996-07-09 Mcgregor; Gerald C. Bicycle alarm system
US5751227A (en) * 1994-12-22 1998-05-12 Nippondenso Co., Ltd. Communication system for vehicles
US5671362A (en) * 1995-04-04 1997-09-23 Cowe; Alan B. Materials monitoring systems, materials management systems and related methods
US5798693A (en) * 1995-06-07 1998-08-25 Engellenner; Thomas J. Electronic locating systems
US5640002A (en) * 1995-08-15 1997-06-17 Ruppert; Jonathan Paul Portable RF ID tag and barcode reader
US5627517A (en) * 1995-11-01 1997-05-06 Xerox Corporation Decentralized tracking and routing system wherein packages are associated with active tags
US5785181A (en) * 1995-11-02 1998-07-28 Clothestrak, Inc. Permanent RFID garment tracking system
US5855988A (en) * 1995-11-27 1999-01-05 Nippon Paint Co., Ltd. Electromagnetic wave absorbing shielding material
US5963927A (en) * 1996-01-31 1999-10-05 Neopost Limited Mailing system
US5828693A (en) * 1996-03-21 1998-10-27 Amtech Corporation Spread spectrum frequency hopping reader system
US5850187A (en) * 1996-03-27 1998-12-15 Amtech Corporation Integrated electronic tag reader and wireless communication link
US6097301A (en) * 1996-04-04 2000-08-01 Micron Communications, Inc. RF identification system with restricted range
US6842121B1 (en) * 1996-04-04 2005-01-11 Micron Technology, Inc. RF identification system for determining whether object has reached destination
US5887176A (en) * 1996-06-28 1999-03-23 Randtec, Inc. Method and system for remote monitoring and tracking of inventory
US6538564B1 (en) * 1997-01-17 2003-03-25 Integrated Silicon Design Pty Ltd Multiple tag reading system
US5920287A (en) * 1997-01-21 1999-07-06 Widata Corporation Radio location system for precisely tracking objects by RF transceiver tags which randomly and repetitively emit wideband identification signals
US6144301A (en) * 1997-02-10 2000-11-07 Safetrac Control Systems, Inc. Electronic tracking tag
US5971587A (en) * 1997-08-01 1999-10-26 Kato; Kiroku Package and mail delivery system
US6121544A (en) * 1998-01-15 2000-09-19 Petsinger; Julie Ann Electromagnetic shield to prevent surreptitious access to contactless smartcards
US7175084B2 (en) * 2000-05-03 2007-02-13 Axalto Sa Integrated circuit card and case therefor
US7163152B2 (en) * 2004-12-15 2007-01-16 Osborn Warren R Protective container for readable cards
US20060187061A1 (en) * 2005-02-07 2006-08-24 Colby Steven M Radio frequency shielding
US7482925B2 (en) * 2005-06-24 2009-01-27 Visa U.S.A. Apparatus and method to electromagnetically shield portable consumer devices
US20070040653A1 (en) * 2005-08-16 2007-02-22 Potts Kevin L Rfid shielding devices

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7639141B2 (en) 1998-03-27 2009-12-29 Keystone Technology Solutions, Llc Systems and methods for identifying lost or stolen devices
US20080024303A1 (en) * 1998-03-27 2008-01-31 Micron Technology, Inc. Systems and methods for identifying missing items
US20070252697A1 (en) * 1998-03-27 2007-11-01 Micron Technology, Inc. Method and system for identifying missing items
US20080012711A1 (en) * 1998-03-27 2008-01-17 Micron Technology, Inc. Systems and methods for identifying lost or stolen devices
US7982608B2 (en) * 1998-03-27 2011-07-19 Round Rock Research, Llc Method and system for identifying missing items
US8395506B2 (en) * 1998-03-27 2013-03-12 Round Rock Research, Llc Method and system for identifying missing items
US20130257618A1 (en) * 1998-03-27 2013-10-03 Round Rock Research, Llc Methods and system for identifying lost or stolen RFID devices
US7755490B2 (en) 1998-03-27 2010-07-13 Round Rock Research, Llc Systems and methods for identifying missing items
US8269605B2 (en) 1999-08-09 2012-09-18 Round Rock Research, Llc RFID material tracking method and apparatus
US7808367B2 (en) 1999-08-09 2010-10-05 Round Rock Research, Llc RFID material tracking method and apparatus
US8378789B2 (en) 1999-08-09 2013-02-19 Round Rock Research, Llc RFID material tracking method and apparatus
US8125316B2 (en) 1999-08-09 2012-02-28 Round Rock Research, Llc RFID material tracking method and apparatus
US20090210517A1 (en) * 2002-05-30 2009-08-20 Sony Corporation Information management device and method, information processing device and method recording medium, and program
US7671721B2 (en) * 2003-05-12 2010-03-02 Valtion Teknillinen Tutkimuskesus Remote sensor, device and method for activating selected remote sensor components
US20060202802A1 (en) * 2003-05-12 2006-09-14 Seppae Heikki Remote sensor, device and method for activating selected remote sensor components
US8289164B2 (en) 2003-12-12 2012-10-16 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US7546137B2 (en) * 2005-02-28 2009-06-09 Sirit Technologies Inc. Power control loop and LO generation method
US20070066223A1 (en) * 2005-02-28 2007-03-22 Sirit, Inc. Power control loop and LO generation method
US8000674B2 (en) * 2007-07-31 2011-08-16 Intel Corporation Canceling self-jammer and interfering signals in an RFID system
US20090036082A1 (en) * 2007-07-31 2009-02-05 Mohammed Sajid Canceling self-jammer and interfering signals in an rfid system
US20110082810A1 (en) * 2008-01-10 2011-04-07 Walt-Task, Llc Human-readable baggage and cargo routing identification system
US9171448B1 (en) * 2014-06-11 2015-10-27 Target Brands, Inc. RFID tags for locating products
US20180204030A1 (en) * 2017-01-13 2018-07-19 International Business Machines Corporation Baggage handling
US10055620B2 (en) * 2017-01-13 2018-08-21 International Business Machines Corporation Baggage handling
US20210072375A1 (en) * 2017-05-10 2021-03-11 Google Llc Low-Power Radar
CN108573182A (en) * 2018-04-26 2018-09-25 深圳市盛路物联通讯技术有限公司 A kind of radio frequency signal communication method and system

Also Published As

Publication number Publication date
US6842121B1 (en) 2005-01-11
US20120274450A1 (en) 2012-11-01
US6097301A (en) 2000-08-01

Similar Documents

Publication Publication Date Title
US6097301A (en) RF identification system with restricted range
US20050040961A1 (en) RF identification system with restricted range
US5627517A (en) Decentralized tracking and routing system wherein packages are associated with active tags
JP6880285B2 (en) Methods and systems for managing shipments of goods using wireless node networks
US7932812B2 (en) Wide area and large capacity intelligent object tracking system and method
CN101027700B (en) Method and apparatus for detection and tracking of objects within a defined area
US7030760B1 (en) Method and apparatus for ensuring reliable loading of materials on aricraft and other vehicles
US9194932B2 (en) Method and system for airplane container tracking
US7916025B2 (en) Intelligent luggage tag
EP3311327B1 (en) Wearable radio frequency identification system
CN1332350C (en) Method and apparatus for tracking devices using tags
US8310379B2 (en) Monitoring device for a tracking system
US9026041B2 (en) Portable radio-frequency repeater
KR20020087470A (en) Signalling system and a transponder for use in the system
US6724306B1 (en) Luggage locating system
EP1481364A1 (en) A communication system
NO20180332A1 (en) Electronic tag device with communication module
AU2017101350A4 (en) Interact Baggage Tracking Unit The Interact Baggage Handling Unit is a non-intrusive (hands free), portable , self container , self powered , wireless communicative baggage tracking device that consists of hardware components and software programs that support three technologies ( Barcode Technology , RFID Technology & BLE Beacon Technology) and applicable to track baggage along its baggage journey in real time and applicable to the travel industry.
WO2007144167A2 (en) System and method for handling objects using sensors to trigger processing of rfid response signals
CN216927622U (en) Airport wearable luggage identification system based on RFID technology

Legal Events

Date Code Title Description
AS Assignment

Owner name: ROUND ROCK RESEARCH, LLC,NEW YORK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MICRON TECHNOLOGY, INC.;REEL/FRAME:023786/0416

Effective date: 20091223

Owner name: ROUND ROCK RESEARCH, LLC, NEW YORK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MICRON TECHNOLOGY, INC.;REEL/FRAME:023786/0416

Effective date: 20091223

AS Assignment

Owner name: MICRON TECHNOLOGY, INC., IDAHO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KEYSTONE TECHNOLOGY SOLUTIONS, LLC;REEL/FRAME:023839/0881

Effective date: 20091222

Owner name: MICRON TECHNOLOGY, INC.,IDAHO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KEYSTONE TECHNOLOGY SOLUTIONS, LLC;REEL/FRAME:023839/0881

Effective date: 20091222

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION