US20080157972A1 - Reverse infrastructure location system and method - Google Patents
Reverse infrastructure location system and method Download PDFInfo
- Publication number
- US20080157972A1 US20080157972A1 US12/050,784 US5078408A US2008157972A1 US 20080157972 A1 US20080157972 A1 US 20080157972A1 US 5078408 A US5078408 A US 5078408A US 2008157972 A1 US2008157972 A1 US 2008157972A1
- Authority
- US
- United States
- Prior art keywords
- rfid
- tag
- rfid tag
- tags
- rfid tags
- 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
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO 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
- G01S13/00—Systems 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
- G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
- G01S13/876—Combination of several spaced transponders or reflectors of known location for determining the position of a receiver
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO 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
- G01S13/00—Systems 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
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/46—Indirect determination of position data
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO 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
- G01S13/00—Systems 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
- G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
- G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K17/00—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO 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
- G01S13/00—Systems 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
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/46—Indirect determination of position data
- G01S2013/466—Indirect determination of position data by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
Abstract
Embodiments include methods and systems by which an object can be located within an area. The system includes a moveable radio frequency identification (RFID) tag reader and multiple RFID tags, which are positioned at known locations. The RFID tag reader is associated with the object, and is adapted to interrogate the RFID tags, to receive unique identifiers from responding RFID tags, to correlate the unique identifiers with tag location information stored in memory to determine fixed positions for the responding RFID tags, and to mathematically determine at least one location solution for the RFID tag reader using the fixed positions. A responding RFID tag is adapted to respond to an interrogation signal from the RFID tag reader by transmitting a unique identifier.
Description
- This application is a continuation of and claims the benefit of the filing date of co-pending, nonprovisional U.S. patent application Ser. No. 10/954,967, filed on Sep. 29, 2004.
- Embodiments of the present invention generally relate to position location, and more particularly to determining the position of a mobile object in real time.
- There are many applications today where it is desired to determine the location of a moveable object. For example, there is often a need to locate a moveable person, forklift, pallet or other cargo carrier in a warehouse, storage depot, factory or other area. In the past this has often been accomplished by placing a radio frequency (RF) beacon on the moveable object and then providing multiple infrastructure receivers at known locations in the area that receive signals from the moveable object and through trilateration or other proximity detectors determine the location of the moveable object within the area. While this arrangement works, it suffers from a number of disadvantages well known in the art, as for example, complexity, high installation cost, limited resolution, undesirably high power drain for the mobile beacon transmitter, and so forth. A further difficulty with this approach is that it is often very difficult to retrofit an existing structure or area to reliably use this approach since it is sensitive to multi-path, reflections and other structure dependant signal artifacts.
- The positions of the trilateration receivers are known and the location of the moveable object (and its beacon transmitter) is unknown until its signal is read and analyzed by the trilateration receivers. The moveable object itself is ordinarily not self-aware, that is, it does not know its own location unless such information is sent to it from the base station managing the trilateration receivers or provided by some other means. Ordinarily, such a system cannot easily handle multiple moveable objects unless different frequencies and duplicate or multi-frequency trilateration receivers are provided, thereby adding further complexity. The infrastructure cost is significant because of the complexity and interconnection of the fixed trilateration receivers.
- In a different application, it is also known to use radio frequency identification (RFID) tags to identify and at least crudely track large numbers of individual moveable items within an area. For example, each pallet or package of goods entering a storage yard, warehouse, factory or other area can be equipped with an RFID tag bearing a unique identifier (unique ID). When interrogated by an RFID tag reader, each tag responds with its unique ID indicating that it is present within signaling range of the reader. Thus, its position is known to be within the signaling range of the RFID tag reader. The RFID tags may be passive, semi-passive or active, depending upon the needs of the user. Such RFID tags are well known and widely available. In the conventional RFID tag installation, the location of the tag reader may or may not be known and the presence and rough location of the RFID tags themselves are unknown until interrogated by the reader. A single tag reader can detect the presence of a large number of tags. The ability of such a system to locate the RFID tags depends upon the proximity of the tag reader and it is ordinarily used to determine whether the tagged objects are present or absent, rather than to determine their exact location.
- Thus, a need continues to exist for an improved position locating apparatus and method, especially one that takes advantage of present day RFID tag technology. Further it is desirable that such improved system be easy to retrofit into existing structures and areas. It is further desirable that such a system be able to take advantage of conventional infrastructure that may already exist in the area desired to be equipped with a position locating system and not require significant new infrastructure installation.
- Accordingly, it is desirable to provide an improved position measuring apparatus and method, especially for measuring the position of moveable objects within an area or building. In addition, it is desirable that the sensing apparatus and method be simple, rugged and reliable and not require any substantial modifications to building infrastructure or the installation of significant complex new infrastructure. Furthermore, other desirable features and characteristics of embodiments of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
- An embodiment includes a system by which an object can locate itself within an area. The system embodiment includes multiple radio frequency identification (RFID) tags and a moveable RFID tag reader. The multiple RFID tags are positioned at known locations within the area, and a responding RFID tag of the multiple RFID tags is adapted to respond to an interrogation signal from an RFID tag reader by transmitting a unique identifier. The moveable RFID tag reader is associated with the object and in signaling contact with at least some of the RFID tags. The RFID tag reader is for interrogating at least some of the RFID tags and for receiving two or more unique identifiers from two or more responding RFID tags, and for correlating the two or more unique identifiers with tag location information stored in memory to determine fixed positions for each of the two or more responding RFID tags, and for mathematically determining at least one location solution for the RFID tag reader within the area using the fixed positions.
- Another embodiment includes a method for determining the position of an object equipped with an RFID tag interrogator within an area having multiple RFID tags in known locations. The method includes interrogating multiple RFID tags by the RFID tag interrogator transmitting an interrogation signal, receiving information from two or more responding RFID tags of the multiple RFID tags, where such information includes two or more unique identifiers transmitted by the two or more responding RFID tags, correlating the two or more unique identifiers with tag location information stored in memory to determine fixed positions for each of the two or more responding RFID tags, and mathematically determining at least one location solution for the RFID tag interrogator within the area using the fixed positions.
- Embodiments of the present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
-
FIG. 1 is a simplified, partial cut-away, perspective view of a mobile device locating system operating according to an embodiment of the present invention; -
FIG. 2 is a simplified schematic diagram of the mobile device locating system ofFIG. 1 showing further details; -
FIGS. 3-4 are simplified schematic diagram of infrastructure RFID tags according to several embodiments of the present invention; -
FIG. 5 is a simplified schematic diagram illustrating capacitive and/or inductive coupling of an RFID infrastructure tag to an infrastructure light fixture for energy harvesting; -
FIGS. 6A-B are simplified side views of typical light fixtures with RFID infrastructure tags of embodiments of the present invention optically coupled thereto, according to a first embodiment; -
FIGS. 7A-B are simplified diagrams illustrating how operation of a fluorescent lamp can affect the “RADAR cross section” (RCS) of the bulb; -
FIG. 8 is a simplified block diagram of a fluorescent lamp ballast modified to cause the lamp to act as a location beacon transmitter, according to an embodiment of the present invention; -
FIG. 9 is a simplified flow diagram of the method of the present invention according to a first embodiment; -
FIG. 10 is a simplified flow diagram of the method of the present invention according to a further embodiment. - The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
- It has been found that many of the problems associated with prior art real time position locating systems can be avoided by using what can be referred to as “reverse RFID” or “reverse infrastructure” position location. In this arrangement, multiple RFID tags are provided in known locations within the work area, and the mobile terminal acts as a tag interrogator and/or reader to determine its position based on the known positions of the tags it interrogates. In the preferred embodiment, the tags are located in, on or in association with light fixtures since such infrastructure generally already exists in most buildings or areas of interest, and tag installation cost is minimal. However, other convenient infrastructure elements can also be used.
-
FIG. 1 is a simplified, partial cut-away, perspective view of mobiledevice locating system 10 according to an embodiment of the present invention.System 10 is shown, by way of example, installed in warehouse or other goods storage area orworkspace 12. For simplicity of illustration, the storage racks, pallets, assembly or packing lines and other facilities that would ordinarily be present in warehouse orworkspace 12 are omitted fromFIG. 1 . Whilearea 12 is identified as a warehouse or goods storage area, this is merely for convenience of description and not intended to be limiting.Area 12 can equally well be a factory, office or administrative area, hospital or other care facility, interior or exterior space or any facility where items, terminals and/or people whose current location is desired to be monitored are being used. Hence, the words “warehouse” and “workspace” are intended to include such alternative locations. -
System 10 comprisesinfrastructure RFID tags 14 installed in this example onlight fixtures 16, and mobile terminal andtag readers FIG. 1 ,mobile terminal 17 is attached to or associated withforklift 18, and mobile terminal 17′ is being carried byperson 19. It will be understood thatforklift 18 andperson 19 are merely exemplary and not intended to be limiting and thatmobile terminals Light fixtures 16 are a convenient and generally existing infrastructure that may be used for this purpose but any other infrastructure equipment present in sufficient quantity and distribution may also be used. Accordingly, while placing infrastructure RFID tags 14 in, on or associated withlight fixtures 16 is preferred, the use of other infrastructure elements as locations for RFID tags 14 is not excluded. -
FIG. 2 is a simplified schematic diagram of mobiledevice locating system 10 ofFIG. 1 showing further details. Each moveable object orperson tag interrogator terminal FIG. 2 byreference number 17.Various infrastructure locations 16 withinspace 12, e.g., infrastructure locations or items 16-1, 16-2, 16-3 . . . 16-N, are equipped withinfrastructure tags 14, e.g., tags 14-1, 14-2, 14-2 . . . 14-N having antennas 14′ e.g., 14-1′. 14-2′. 14-3′, . . . 14-N′, respectively.Interrogator 17 comprisesRFID interrogation transceiver 30 with antenna(s) 23, 23′ for sending and receivingsignals tags 14.Interrogator 17 also comprisesprocessor 32 andmemory 34 which are coupled bydata bus 31 to each other and totransceiver 30.Power supply 38 supplies power to these components via power leads 37, 39. As will be explained later, additional functions are desirably but not essentially included interminal 17. While use of separate transmitantenna 23 and receiveantenna 23′ is convenient, it is not essential and a single antenna may be used for both functions. Hereafter, for convenience ofdescription reference number 23 is used to refer collectively to antenna (s) 23 and 23′. -
RFID transceiver 30 ofinterrogator 17 sendsinterrogation signal 20 viaantenna 23 toinfrastructure tags 14 in its vicinity, e.g., tags 14-1, 14-2, 14-2 . . . 14-N, associated with known infrastructure locations 16-1, 16-2, 16-3, . . . 16-N. Interrogation signal 20 is received by some or all of antennas 14-1′, 14-2′, 14-3′, . . . 14-N′ associated respectively with tags 14-1, 14-2, 14-2 . . . 14-N. Tags 14 respond with at least, their unique identifiers (unique IDs), which are received by dual function transmit/receiveantenna 23 or alternatively by separate receivingantenna 23′ of transceiver 30 (either arrangement is useful). It is desirable that eachinfrastructure tag 14 also respond with its location but this is not essential since the tag's positions are fixed oninfrastructure elements 16 having known locations and each tag's unique ID can be correlated with the tag's location stored in memory, for example, withinmemory 34 ofinterrogator 17 or within memory inbase station 44 or elsewhere. It will be noted that the unique tag ID may merely be the tag location coordinates (or translatable into its location coordinates) since each location is unique and a separate unique tag ID is not needed although not precluded. Either arrangement is useful. It is also desirable but not essential thatinterrogator 17 be able to vary the strength of its interrogation signal and/or adjust its receive sensitivity and/or measure the relative signal strength of the responses received from the various tags 14. This is conveniently accomplished byRFID transceiver 30 in cooperation withprocessor 32 andmemory 34. - The responses received from
tags 14 are used byinterrogator 17 to determine its position with varying degrees of accuracy depending upon the needs of the user. For example, by initially broadcasting its interrogation signal at low power,interrogator 17 may receive no responses and then successively increase the transmitted power level until, for example, only one tag (e.g., tag 14-2) or a small number of tags (e.g., tags 14-2, 14-3) respond. This immediately establishes the position ofinterrogator 17 as being in close proximity to the responding tag(s). A similar result may be accomplished by measuring the signal strength of the received responses since, in general, the closer the tag, the stronger the received signal. In this manner the closest tags and therefore the approximate location of terminal 17 may be determined. The level of accuracy obtained by the above-described proximity detection may be sufficient in many applications wherelocations 16 withtags 14 are relatively closely spaced. When greater accuracy is desired and/orinfrastructure locations 16 andtags 14 are more widely spaced,transceiver 30 in cooperation withprocessor 32 andmemory 34 may determine the phase difference of arrival (PDOA) and/or time difference of arrival (TDOA) ofsignals 20. 20′ fromvarious tags 14 and use this information to locate its position relative to the responding tags. PDOA and TDOA ranging techniques are well known in the art. Generally, signals received from at least two and preferably three spaced-apart infrastructure tags 14 are sufficient to permit a unique determination of range by PDOA and/or TDOA from respondingtags 14. When the range to and position of the responding tags is known, the position ofinterrogator 17 relative toinfrastructure elements 16 wheretags 14 are located may be determined mathematically. Responses from three spaced-apart tags provide a single terminal location solution and responses from two spaced-apart tags provide two possible terminal location solutions, one true and one false. However, even a two tag solution can be used to determine a unique location by using other available information to eliminate the “false” solution. For example, if one of the two possible solutions from two-tag responses is within the actual workspace and the second possible solution is outside the actual workspace or in an inaccessible location or would require that the terminal jump a wall to move from its last determined location, and so forth, the second solution can be discarded on logical grounds as being physically unrealizable or unlikely. Hence, even two tag responses are often sufficient to provide a unique position determination using trilateration combined with logical inferences from other available information. -
Terminal 17 may also includeprimary function 36 and/orsystem transceiver 40.Primary function 36 can be any convenient function incorporated interminal 17 to suit the needs of the user. For example and not intended to be limiting,primary function 36 can be a bar code reader, an inventory checker, a cell phone or other communicator, a hazmat detector or other measuring instrument of some sort or whatever other function or combination of functions is needed by the user.Terminal 17 may also includesystem transceiver 40 for communicating viaantenna 42 and wireless link 43 withbase station 44 to which it may report or receive various data generated or used byprimary function 36 and/orprocessor 32.System transceiver 40 may also be used to report the location of terminal 17 determined byRFID transceiver 30,processor 32 andmemory 34. For an embodiment of the present invention, real time location ofterminal 17 is preferably (but not essentially) performed withinterminal 17 itself, using response signals obtained frominfrastructure RFID elements 14 having known fixed locations oninfrastructure elements 16. Alternatively, terminal 17 may receive the response signals fromRFID beacons 14, transmit this information viatransceiver 40 tobase station 44 where the actual position determining calculations and/or logical operations are performed. Either arrangement works.System transceiver 40 andprimary function 36 are desirably also coupled todata bus 31 and power supply leads 37, 39. While it is preferred that terminal 17 generateinterrogation signal 20, this is not essential, and the interrogation signal may originate elsewhere in system 10 (e.g., from a separate interrogation transmitter, not shown) provided that terminal 17 can obtain range and/or location information from respondingtags 14.Terminal 17 can obtain proximity information by varying its transmit power and/or receive sensitivity where it is sending outsignal 20 or by varying its receive sensitivity where another element is providinginterrogation signal 20. Either arrangement is useful. -
FIGS. 3-4 are simplified schematic diagrams of infrastructure RFID tags 141, 142 according to several embodiments of the present invention.Reference number 14 inFIGS. 1-2 is intended to includeimplementations FIGS. 3-4 and equivalents.Tag 141 ofFIG. 3 comprisesantenna 150, energy harvesting and AM demodulator (EH&DeMod)circuit 152,processor 154,non-volatile memory 156,regulator 158 andbackscatter switch 168. Whentag 141 is configured as a passive tag,line 157 fromEH&DeMod circuit 152 supplies DC energy toregulator 158 which powersprocessor 154 andbackscatter switch 168. With this arrangement, no self-contained or external DC power input is required. Such tags are well known in the art. Whentag 141 receivessignal 20, it is coupled to amplitude shift keyed (ASK)portion 153 ofprocessor 154 which determines that the tag is being interrogated and responds by havingbackscatter portion 155 ofprocessor 154 activatebackscatter switch 168 via lead(s) 159. Whenbackscatter switch 168 is closed,antenna 150 is shorted to local ground (e.g., the counterpoise of a dipole antenna) thereby changing the load presented to transmitting antenna 23 (seeFIG. 2 ) and therefore its spatial impedance, i.e. its “RADAR cross section” (RCS). This change in spatial impedance (RCS) is sensed bytransceiver 30 ofinterrogator 17. By closing andopening backscatter switch 168 at a predetermined rate and/or in a predetermined sequence,tag 141 provides its unique ID or other information from which its known position can be determined. The actual position coordinates of the beacon tag relative to the workspace can be used as its unique ID, but this is not essential. No external power other thaninterrogation signal 20 is required to operatetag 141 in the fully passive mode. However, optional battery or otherenergy storage device 160 andcharger 162 may also be provided to enabletag 14 to operate at higher power levels and longer range in a semi-passive mode. Wheretag 141 is mounted in proximity tolight fixtures 16,optional photocell 164 may also be provided to charge battery orenergy cell 160 and/or directly driveregulator 158. This is convenient but not essential. - Referring now to tag 142 of
FIG. 4 , the same reference numbers are used to identify like functions or elements as inFIG. 3 , and the discussion ofFIG. 3 concerning these common elements is incorporated herein by reference.Tags tag 142 ofFIG. 4 includes inductive/capacitive (I/C)coupling antenna 172 and/or lightbulb backscatter switch 170, collectively identified byreference number 180. These functions provide alternative means by which tag 142 can harvest energy and respond tointerrogation signal 20. For example, whentag 142 is operated in the conventional manner,circuit 152 harvests energy fromincoming signal 20 and far-field backscatter portion 155-1 ofprocessor 154′ activates far-field backscatter switch 168 over lead(s) 159 in the same manner as fortag 141. However,tag 142 provides an alternative means of harvesting energy and responding tointerrogation signal 20. Inductive/capacitive (I/C)coupling antenna 172 is provided in close proximity to, for example,light fixture 16 with which tag 142 is associated, so that A/C energy derived from the light fixture (e.g., seeFIG. 5 ) is coupled fromantenna 172 viacapacitor 171, rectifier-filter 173 and lead 157 toregulator 158 to driveprocessor 154′, etc.Antenna 172 operates independently fromantenna 150 and provides additional energy, or an alternate source of energy, to drivecircuit 152. While light 16 is on,tag 142 can operate in a semi-passive or active mode since it is not dependent merely on harvesting energy fromincoming interrogation signal 20. Lightbulb backscatter switch 170 driven by light bulb backscatter portion 155-2 ofprocessor 154′ via lead (s) 161 is as an alternative means by which tag 142 can respond tointerrogation signal 20. Depending upon the nature oflight fixture 16 to whichtag 142 is coupled, the light output or other electromagnetic radiation produced by the light fixture may be modulated byswitch 170 to provide a response signal detectable bytransceiver 30. This is explained more fully in connection withFIGS. 7-8 . -
FIG. 5 illustrates in simplified schematic form how contact-less inductive/capacitive coupling may be achieved for energy harvesting while still using far-field backscattering. Electrical outlet orsocket adaptor 191 is provided which couples, for example, to the primary power mains of the light fixture either alongside the light fixture connection or between the light fixture connection and the power mains. In either case, it draws power from the same source as the light fixture to which the tag is attached or coupled. Coil orfield plate 192 is provided in close proximity to a mating coil or field plate (e.g., antenna 172) ontag 14 so that the AC energy derived from the light fixture supply is coupled to the tag, for example using the circuit as shown inFIG. 4 . -
FIGS. 6A-B are simplified side views of typical light fixtures 200-203 with RFID infrastructure tags 204-207 of embodiments of the present invention coupled thereto. Infrastructure tags 204-206 are examples of infrastructure tags 14 described earlier. Referring now toFIG. 6A ,light fixture 200 suspended from ceiling orother support 210 emits light 212 generally in a downward direction.Infrastructure RFID tag 204 withantenna 204′ is mounted onsupport 211 coupled to light fixture 200 (or other support) so thatportion 214 oflight 212 impinges onoptional photocell 216 analogous tophotocells 164 described earlier.Photocell 216 is not essential but is desirable since it can provide power toinfrastructure tag 204 without need to connect any wires to themains powering fixture 200 and/or act as a turn-on switch to automatically activatetag 204 when light 200 is energized. In somecases fixture 200 may emit stray light 213 from the side or rear offixture 200, in whichcase infrastructure tag 205 withantenna 205′ (analogous to tag 204 andantenna 204′) may be mounted onsupport 215 so as to havephotocell 217 intercept light 213 in the same manner and for the same purpose asphotocell 216 oftag 204 intercepts light 214. Either arrangement is useful. -
FIG. 6B shows typical fluorescenttype light fixture 201 suspended from ceiling orother support 210′.Fixture 201 typically hasbase 220 with clear ortranslucent cover 222 within which fluorescentlight tube 224 is located.Fluorescent tube 224 emits light 226 in multiple directions whereinportion 228 of light 226 falls onphotocell 230 attached, for example, to cover 222 by any convenient means (e.g., adhesive, mounting screws, etc.). Wire(s) 232 are provided to couple photocell 230 toinfrastructure tag 206.Tag 206 may be located anywhere in, on ornear fixture 201. -
FIGS. 7A-B are simplified diagrams oflight fixture 240 illustrating how operation offluorescent lamp 242 can affect the spatial impedance i.e. the “Radar cross section” (RCS) oflamp 242.Light fixture 240 is a typical modern fixture employingelectronic ballast 244. Power is generally supplied toballast 244 offixture 240 from A/C mains 246, although this is not essential. A DC power source can also be used.Electronic ballast 244 transforms the input supply voltage into whatever form is needed to run lamp 242 (e.g., seeFIG. 8 ). Contained withinballast 244 is switching orchopper circuit 248, represented inFIGS. 7A-B assimple switch 247.Switch 247 is shown in the open position inFIG. 7A and in the closed position inFIG. 7B . Nearby terminal 17 withantenna 23 sends, e.g.,RF signal 20 towardlight fixture 240. Whenswitch 247 is open,gas 250 withinlamp 242 is not ionized and is essentially transparent toRF signal 20 so that most ofsignal 20 passes throughlamp 242 undisturbed. - When
switch 247 is closed, voltage is applied togas 250 and it becomesionized gas 250′ and emits light 252.Ionized gas 250′ is electrically conductive so thatportion 20″ of RF signal 20 fromantenna 23 ofterminal 17 is now reflected back towardantenna 23. The spatial impedance, i.e. the RCS of thelamp 242, changes significantly depending upon the state of ionization ofgas 250 oflamp 242. As is explained more fully in connection withFIG. 8 , this can be used to turnfixture 240 into an RFID position location beacon. Further, becauseswitch 247 is effectively opening and closing at a rate of, typically, 30-130 kHz,lamp 242 offixture 240 changes reflectance and re-radiates significant electromagnetic energy somewhere in this frequency range and harmonics thereof. For convenience of explanation, it is assumed hereafter thatlamp 242 is being excited at approximately 60 kHz, but this is not intended to be limiting, and any convenient frequency can be used. -
FIG. 8 is a simplified schematic block diagram offluorescent fixture 260 wherein operation ofconventional lamp ballast 244 is modified to causelamp 242 to act as a location beacon according to an embodiment of the present invention.Mains source 246 typically provides primary AC energy to AC toDC converter circuit 262 which converts the incoming AC to DC for use by frequency determining clock or resonator 264 and lamp driver 266. The output of clock or resonator 264 is typically fed to lamp driver 266 that provides the necessary 60 kHz excitation voltage and current control tolamp 242.Elements 262, 264, 266 making upordinary ballast 244 are conventional and take many different forms. For example, elements 264, 266 may be combined into a resonant analog circuit tuned to the desired output frequency to provide the 60 kHz excitation tolamp 242. Alternatively,ballast 244 may be digital, managed by an integrated circuit (IC) whose output frequency is determined by an internal digital clock. Such arrangements are well known in the art andelements 262, 264, 266 ofballast 244 shown inFIG. 8 are merely intended to indicate generally that the above-described functions exist in some form withinballast 244 and not be limited to merely the above-described elements.Gas 250 withinlamp 242 is ionized and de-ionized at a 60 kHz rate. -
Ballast 272 of an embodiment of the present invention, differs fromconventional ballast 244 by addition ofmodulator 270 andunique ID 268.Unique ID 268 is conveniently stored in non-volatile memory and represents the location or location address of the light fixture to whichballast 272 is attached. Thus,unique ID 268 provides the position information needed to be backscattered or otherwise transmitted byRFID beacon 14, e.g.,fixture FIGS. 7-8 employingballast 272.Modulator 270 is coupled to frequency determining element 264 so as to cause the output frequency, and therefore the excitation (ionization/deionization) frequency oflight fixture 260 to vary about the unmodulated e.g., 60 kHz, excitation frequency. After modulation, the electromagnetic energy inherently radiated byfixture ballast 272 now contains the unique ID information associated with its position within workspace 10 (seeFIG. 1 ). Thus, signal 20″ received byantenna 23 ofterminal 17 inherently contains the desired position location information concerninglight fixture light fixture Terminal 17 can detect this position information merely by detecting and/or decoding the modulated switching frequency backscattered or otherwise transmitted byfixture - In a further embodiment,
interrogation receiver 274 coupled tomodulator 270 is included inballast 272′. In this embodiment,modulator 270 is dormant untilreceiver 274 receives an interrogation signal broadcast byterminal 17. This interrogation signal causes modulator 270 to become active so thatfixture signal 20″. In this way, only those fixtures within range ofterminal 17 are backscattering or otherwise transmitting a position modulated signal.Modulator 270 may remain active as long as an interrogation signal is being received or may time-out after a predetermined interval or a combination thereof. - While the foregoing embodiments of the present invention have been described for fluorescent lamps, persons of skill in the art will understand based on the description herein that they are applicable to any type of lamp in which ionized gas is used to provide light. Fluorescent, sodium vapor, mercury vapor and other types of gas discharge lamps are non-limiting examples of gaseous ionization type of light sources. Thus, the terms “fluorescent” and gas “ionization” and “deionization” are intended to include all forms of gas ionization lamps.
-
FIG. 9 is a simplified flow diagram ofmethod 300 of the present invention according to a first embodiment.Method 300 begins withSTART 302, which desirably occurs on power-up. For example, for those infrastructure tags coupled to light fixtures, START desirably occurs when the fixtures are switched on but this is not essential since it may be desirable to have the locating system working even when some or all of the lights are off. Ininitial step 304, terminal 17 sends an interrogation signal to the nearby tags 14. Step 304 is intended to include determining the presence of sidebands produced by the spatial impedance modulation ofantenna 23 byterminal 17 for the embodiments illustrated inFIGS. 7-8 . Inquery 306 it is determined whether or not a response is detected byterminal 17. Ignoring for the momentoptional step 308, when the outcome ofquery 306 is YES (TRUE), abbreviated inFIG. 9 as “Y”,method 300 proceeds to step 310 wherein the location(s) of the responding tag(s) are determined. This may involve looking up in memory the locations based on the unique IDs received form the responding tags or the tag responses themselves may include coordinates of the tags relative to the workspace. Instep 312 the terminal location is determined using the information obtained instep 310. As described earlier, optional logicalerror check step 313 may be performed depending upon the number of tags that have responded to resolve any ambiguities in terminal position. Instep 314, the terminal location is reported in a manner desired by the system designer or user, as for example viatransceiver 40 ofFIG. 2 , but any method of reporting including visual and/or audible announcement(s) may also be used. Followingstep 314,method 300 returns to START 302 andinitial step 304 as shown bypath 315. While it is desirable that one or both oflocation steps terminal 17 this is not essential and the received tag responses can be sent tobase station 44 and the position location determinations performed there. Either arrangement is useful. - Returning now to step 304 an alternative strategy is to send a first tag interrogation signal at either minimum or maximum power. Consider first starting with minimum interrogation power and/or minimum receiver sensitivity. Then, query 306 desirably responds according to
outcomes 306U, that is, if the outcome ofquery 306 is NO FALSE thenmethod 300 proceeds to step 308 wherein the transmit power and/or receiver sensitivity are changed so as to increase the effective detection range. In this circumstance, transmit power and/or receiver sensitivity are increased and step 304 and query 306 repeated. As long as the outcome ofquery 306 is NO (FALSE) terminal 17 will ratchet up the power and/or receiver sensitivity until the outcome ofquery 306 is YES (TRUE) (outcome 306U) whereuponmethod 300 proceeds to step 310 and following as already described. - Consider now starting with maximum interrogation power and/or maximum receiver sensitivity. Then query 306 desirably responds according to
outcomes 306D, that is, if the outcome ofquery 306 is YES (TRUE) thenmethod 300 proceeds to step 308 wherein the transmit power and/or receiver sensitivity are changed to decrease the effective detection range, i.e., use less transmit power and/or less receiver sensitivity.Steps 304 and query 306 are repeated. As long as the outcome ofquery 306 is YES (TRUE) (outcome 306D) terminal 17 will ratchet down the power and/or receiver sensitivity until the outcome ofquery 306 is NO (FALSE) (outcome 306D) whereuponmethod 300 proceeds to step 310 and following based on the location of the last tag(s) detected. With either the power-up or power-down approach,method 300 determines the terminal location on the basis of the closest tags, i.e., those first detected using power-up and those last detected using power-down. Either arrangement is useful. -
FIG. 10 is a simplified flow diagram ofmethod 400 of the present invention according to a further embodiment.Method 400 begins withSTART 402 that desirably occurs on power-up. For example, for those infrastructure tags coupled to light fixtures, START desirably occurs when the fixtures are switched on but this is not essential since it may be desirable to have the locating system working even when some or all of the lights are off. Ininitial step 404, terminal 17 sends an interrogation signal to nearby tags 14. Step 404 is intended to include determining the presence of sidebands produced by the spatial impedance modulation ofantenna 23 byterminal 17 for the embodiments illustrated inFIGS. 7-8 . Insubsequent step 406 those responding tags having the strongest signal are identified. It will be appreciated that the power-up or power-down strategy described in connection withmethod 300 ofFIG. 10 can also be used inmethod 400 with the proviso that responses from more than one tag are desired. This is determined inquery 408 wherein it is decided whether or not sufficient responses have been received to permit trilateration to be used to determine the range of terminal 17 from the responding tag locations. In general, it is desirable to have responses from at least two, preferably at least three, tags on different bearings to perform reliable trilateration. If the outcome ofquery 408 is NO (FALSE) thenmethod 400 proceeds to step 410 analogous to step 308 ofmethod 300 and steps 404-408 are repeated until a YES (TRUE) outcome is obtained fromquery 408. When enough tags have been detected to permit reliable trilateration, thenmethod 400 proceeds to step 412 wherein the coordinates of the responding tags are determined, for example, directly from the tag IDs or location response or, for example, from a look-up table having tag locations correlated with tag IDs. In followingstep 414, the distances from the tag to the interrogator are determined using, for example PDOA or TDOA comparisons. This provides, for example, two, three or more radii from the known tag locations and instep 416 the trilateration calculation is performed to determine the terminal location, e.g., the intersection of the radii. As described earlier, optional logicalerror check step 417 may be performed, depending upon the number of tags that have responded, in order to resolve any ambiguities in terminal position. Instep 418 analogous to step 314 ofmethod 300, the terminal location is reported as needed andmethod 400 loops back toSTART 402 andinitial step 404 as shown bypath 419. Either ofmethods terminal 17 using the infrastructure RFID tags 14 associated with known infrastructure locations, preferably light fixtures. It will be appreciated by those of skill in the art based on the description herein that existing facilities may be easily retrofitted with RFID infrastructure tags by placing them on or adjacent to available light fixture. In the case of new construction, such tags may be included with the infrastructure, e.g., the light fixtures, when they are installed, and/or the ballasts of the fixtures modified to permit the fixtures themselves to act as position location beacons without addition of an RFID tag. - While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
Claims (20)
1. A system by which an object can be located within an area, the system comprising:
a moveable radio frequency identification (RFID) tag reader associated with the object and in signaling contact with multiple RFID tags positioned at known locations within the area, wherein the RFID tag reader is adapted to interrogate at least some of the multiple RFID tags, to receive two or more unique identifiers from two or more responding RFID tags, to correlate the two or more unique identifiers with tag location information stored in memory to determine fixed positions for each of the two or more responding RFID tags, and to mathematically determine at least one location solution for the RFID tag reader within the area using the fixed positions.
2. The system of claim 1 , further comprising:
the multiple RFID tags, wherein a responding RFID tag of the multiple RFID tags is adapted to respond to an interrogation signal from the RFID tag reader by transmitting a unique identifier.
3. The system of claim 2 , wherein at least some of the multiple RFID tags are associated with light fixtures within the area.
4. The system of claim 3 , wherein the at least some of the multiple RFID tags derive energy from the light fixtures.
5. The system of claim 4 , wherein the at least some of the multiple RFID tags derive energy from the light fixtures by optical coupling.
6. The system of claim 4 , wherein the at least some of the multiple RFID tags derive energy from the light fixtures by inductive coupling.
7. The system of claim 4 , wherein the at least some of the multiple RFID tags derive energy from the light fixtures by capacitive coupling.
8. The system of claim 2 , wherein the unique identifier includes location coordinates of the responding RFID tag.
9. The system of claim 2 , wherein each of the multiple RFID tags also are adapted to respond to an interrogation signal with a location of the RFID tag.
10. The system of claim 1 , wherein the moveable RFID tag reader comprises a primary function.
11. The system of claim 10 , wherein the primary function is a function selected from a group that includes a bar code reader, an inventory checker, a cell phone, and a hasmat detector.
12. The system of claim 1 , wherein the moveable RFID tag reader comprises a transceiver adapted to communicate with a base station.
13. A method for determining the position of an object associated with a radio frequency identification (RFID) tag interrogator within an area having multiple RFID tags in known locations, the method comprising the steps of:
interrogating multiple RFID tags by the RFID tag interrogator transmitting an interrogation signal;
receiving information from two or more responding RFID tags of the multiple RFID tags, wherein such information includes two or more unique identifiers transmitted by the two or more responding RFID tags;
correlating the two or more unique identifiers with tag location information stored in memory to determine fixed positions for each of the two or more responding RFID tags; and
mathematically determining at least one location solution for the RFID tag interrogator within the area using the fixed positions.
14. The method of claim 13 , wherein the interrogating step comprises transmitting an interrogation signal.
15. The method of claim 14 , further comprising:
an RFID tag receiving an interrogation signal from the RFID tag reader; and
the RFID tag responding to the interrogation signal by transmitting a unique identifier.
16. The method of claim 15 , wherein the unique identifier includes location coordinates of the RFID tag.
17. The method of claim 14 , further comprising:
an RFID tag receiving an interrogation signal from the RFID tag reader; and
the RFID tag responding to the interrogation signal with a location of the RFID tag.
18. The method of claim 13 , wherein the interrogating step comprises interrogating an RFID tag associated with a light fixture in the area.
19. The method of claim 18 , further comprising the RFID tag deriving energy from the light fixture.
20. The method of claim 19 , wherein deriving energy from the light fixture comprises deriving energy using an energy derivation technique selected from a group that includes optical coupling, inductive coupling, and capacitive coupling.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/050,784 US20080157972A1 (en) | 2004-09-29 | 2008-03-18 | Reverse infrastructure location system and method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/954,967 US7403120B2 (en) | 2004-09-29 | 2004-09-29 | Reverse infrastructure location system and method |
US12/050,784 US20080157972A1 (en) | 2004-09-29 | 2008-03-18 | Reverse infrastructure location system and method |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/954,967 Continuation US7403120B2 (en) | 2004-09-29 | 2004-09-29 | Reverse infrastructure location system and method |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080157972A1 true US20080157972A1 (en) | 2008-07-03 |
Family
ID=36124992
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/954,967 Expired - Fee Related US7403120B2 (en) | 2004-09-29 | 2004-09-29 | Reverse infrastructure location system and method |
US12/050,784 Abandoned US20080157972A1 (en) | 2004-09-29 | 2008-03-18 | Reverse infrastructure location system and method |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/954,967 Expired - Fee Related US7403120B2 (en) | 2004-09-29 | 2004-09-29 | Reverse infrastructure location system and method |
Country Status (1)
Country | Link |
---|---|
US (2) | US7403120B2 (en) |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080143546A1 (en) * | 2006-12-18 | 2008-06-19 | General Electric Company | Locating system and method |
US20080150696A1 (en) * | 2006-12-21 | 2008-06-26 | Bolander Jarie G | System for powering and reading RFID tags |
US20080220720A1 (en) * | 2004-11-05 | 2008-09-11 | Wirelesswerx International, Inc. | Method and system for providing area specific messaging |
US20090212921A1 (en) * | 2008-02-25 | 2009-08-27 | Wirama Corporation | Localizing tagged assets using modulated backscatter |
US20100117826A1 (en) * | 2008-11-11 | 2010-05-13 | Monster Medic, Inc. | Mobile monitoring and alert system |
CN101858974A (en) * | 2010-06-03 | 2010-10-13 | 清华大学 | Positioning system |
US20110080264A1 (en) * | 2009-10-02 | 2011-04-07 | Checkpoint Systems, Inc. | Localizing Tagged Assets in a Configurable Monitoring Device System |
US20120026016A1 (en) * | 2010-07-27 | 2012-02-02 | The Boeing Company | Wireless Device Association System |
US8537007B2 (en) | 2010-04-08 | 2013-09-17 | Checkpoint Systems, Inc. | Autoaccreting database for EAS-RF applications |
US8963691B1 (en) | 2010-07-27 | 2015-02-24 | The Boeing Company | Sensor association system using wireless device information |
WO2017095664A1 (en) * | 2015-11-30 | 2017-06-08 | Heraeus Noblelight America Llc | Lamps and light sources including rfid tags, and methods of assembling and operating the same |
US10589931B2 (en) | 2016-09-30 | 2020-03-17 | Staples, Inc. | Hybrid modular storage fetching system |
US10638404B1 (en) * | 2018-12-13 | 2020-04-28 | Securus Technologies, Inc. | Controlled-environment facility mobile device location tracking |
US10683171B2 (en) | 2016-09-30 | 2020-06-16 | Staples, Inc. | Hybrid modular storage fetching system |
US10803420B2 (en) | 2016-09-30 | 2020-10-13 | Staples, Inc. | Hybrid modular storage fetching system |
US10949730B2 (en) | 2019-02-15 | 2021-03-16 | International Business Machines Corporation | Leveraging channel diversity in wireless power and communication |
US10965166B2 (en) | 2019-02-15 | 2021-03-30 | International Business Machines Corporaton | Simultaneous wireless power transmission, communication, and localization |
US20210304576A1 (en) * | 2014-01-16 | 2021-09-30 | Automaton, Inc. | Systems and methods for rfid-based retail management |
Families Citing this family (120)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7503478B2 (en) * | 2000-05-01 | 2009-03-17 | Jeffery R Clark | Light fixture management system |
US7422152B2 (en) | 2004-05-13 | 2008-09-09 | Cisco Technology, Inc. | Methods and devices for providing scalable RFID networks |
US7325734B2 (en) * | 2004-05-13 | 2008-02-05 | Cisco Technology, Inc. | Methods and devices for assigning RFID device personality |
US7232069B1 (en) * | 2004-06-16 | 2007-06-19 | Ncr Corporation | Methods and apparatus for disabling, enabling or setting the range of radio frequency identification devices |
KR100682869B1 (en) * | 2004-10-15 | 2007-02-15 | 삼성전기주식회사 | Location tracking system and method |
US7295114B1 (en) * | 2005-01-21 | 2007-11-13 | Alien Technology Corporation | Location management for radio frequency identification readers |
US20060176179A1 (en) * | 2005-01-26 | 2006-08-10 | Battelle Memorial Institute | Bendable, active radio-frequency sensor tags and a system of same |
US7242303B2 (en) * | 2005-03-04 | 2007-07-10 | Cisco Technology, Inc. | Navigation and coordination during emergencies |
US7213768B2 (en) | 2005-03-16 | 2007-05-08 | Cisco Technology, Inc. | Multiple device and/or user association |
US7953826B2 (en) * | 2005-07-14 | 2011-05-31 | Cisco Technology, Inc. | Provisioning and redundancy for RFID middleware servers |
WO2007047510A2 (en) * | 2005-10-14 | 2007-04-26 | Aethon, Inc. | Robotic inventory management |
CN1952602A (en) | 2005-10-18 | 2007-04-25 | 国际商业机器公司 | Method and apparatus for determining the location of a user in an area |
US8456305B2 (en) * | 2005-11-22 | 2013-06-04 | Tell A. Gates | Redundant security system |
US8447234B2 (en) | 2006-01-18 | 2013-05-21 | Qualcomm Incorporated | Method and system for powering an electronic device via a wireless link |
US9130602B2 (en) * | 2006-01-18 | 2015-09-08 | Qualcomm Incorporated | Method and apparatus for delivering energy to an electrical or electronic device via a wireless link |
US20070185749A1 (en) * | 2006-02-07 | 2007-08-09 | Anderson Noel W | Method for tracking hand-harvested orchard crops |
US7443298B2 (en) * | 2006-02-15 | 2008-10-28 | International Business Machines Corporation | Dynamic boundary mapping using position-determination systems |
US20070254674A1 (en) * | 2006-04-28 | 2007-11-01 | Texas Instruments, Inc. | Location Determination With A Wireless System |
US9489813B1 (en) * | 2006-09-22 | 2016-11-08 | Michael L. Beigel | System for location in environment and identification tag |
US7995731B2 (en) * | 2006-11-01 | 2011-08-09 | Avaya Inc. | Tag interrogator and microphone array for identifying a person speaking in a room |
US7756415B2 (en) * | 2006-11-13 | 2010-07-13 | Honeywell International Inc. | Method and system for automatically estimating the spatial positions of cameras in a camera network |
US7541927B2 (en) * | 2006-11-14 | 2009-06-02 | The Boeing Company | Wireless real time location system (RTLS) using audible and/or visible signals |
US20080122696A1 (en) * | 2006-11-28 | 2008-05-29 | Huseth Steve D | Low cost fire fighter tracking system |
US8294554B2 (en) | 2006-12-18 | 2012-10-23 | Radiofy Llc | RFID location systems and methods |
ES2326057B1 (en) * | 2006-12-28 | 2010-06-25 | Vodafone España, S.A. | METHOD FOR IMPROVING TRAFFIC SAFETY THROUGH THE USE OF BEAMS. |
US9774086B2 (en) * | 2007-03-02 | 2017-09-26 | Qualcomm Incorporated | Wireless power apparatus and methods |
US9536215B2 (en) * | 2007-03-13 | 2017-01-03 | Oracle International Corporation | Real-time and offline location tracking using passive RFID technologies |
US9202357B2 (en) * | 2007-03-13 | 2015-12-01 | Oracle International Corporation | Virtualization and quality of sensor data |
US7859408B2 (en) * | 2007-03-28 | 2010-12-28 | Round Rock Research, Llc | Methods and systems of determining physical characteristics associated with objects tagged with RFID tags |
US7880618B2 (en) * | 2007-03-28 | 2011-02-01 | Round Rock Research, Llc | Methods and systems of determining physical characteristics associated with objects tagged with RFID tags |
US20080280560A1 (en) * | 2007-05-09 | 2008-11-13 | Micron Technology, Inc. | Method and system of placing a rfid tag in a continuous transmission mode |
KR20080103254A (en) | 2007-05-23 | 2008-11-27 | 에스케이 텔레콤주식회사 | Method for measuring location of radio frequency identification reader by using beacon |
US8042737B2 (en) | 2007-06-05 | 2011-10-25 | Oracle International Corporation | RFID key rotation system |
DE102007026117B4 (en) * | 2007-06-05 | 2010-10-14 | Siemens Ag | machine tool |
US9507375B2 (en) * | 2007-06-05 | 2016-11-29 | Samsung Electronics Co., Ltd. | Display apparatus and method for recognizing location |
US9124120B2 (en) | 2007-06-11 | 2015-09-01 | Qualcomm Incorporated | Wireless power system and proximity effects |
US7667648B2 (en) * | 2007-06-12 | 2010-02-23 | Alcatel-Lucent Usa Inc. | Facilitating mobile station location using a ground-based cellular network |
US20100225484A1 (en) * | 2007-06-14 | 2010-09-09 | Koninklijke Philips Electronics N.V. | Object localization method, system, tag, and user interface device |
US20090002165A1 (en) * | 2007-06-28 | 2009-01-01 | Micron Technology, Inc. | Method and system of determining a location characteristic of a rfid tag |
JP2010535335A (en) * | 2007-08-01 | 2010-11-18 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | How to determine the position of an object in a structure |
CN101842962B (en) * | 2007-08-09 | 2014-10-08 | 高通股份有限公司 | Increasing the Q factor of a resonator |
EP2188863A1 (en) | 2007-09-13 | 2010-05-26 | QUALCOMM Incorporated | Maximizing power yield from wireless power magnetic resonators |
JP2010539857A (en) * | 2007-09-17 | 2010-12-16 | クゥアルコム・インコーポレイテッド | Transmitter and receiver for wireless energy transmission |
US20090085741A1 (en) * | 2007-09-27 | 2009-04-02 | Symbol Technologies, Inc. | Methods and apparatus for locating an rfid reader using rfid tags |
US7663490B2 (en) * | 2007-09-28 | 2010-02-16 | Intel Corporation | Methods and apparatus for efficiently tracking activity using radio frequency identification |
US7932814B2 (en) * | 2007-10-04 | 2011-04-26 | Round Rock Research, Llc | Method and system to determine physical parameters as between a RFID tag and a reader |
US7944356B2 (en) * | 2007-10-04 | 2011-05-17 | Round Rock Research, Llc | Method and system to determine physical parameters as between an RFID tag and a reader |
WO2009049281A2 (en) * | 2007-10-11 | 2009-04-16 | Nigel Power, Llc | Wireless power transfer using magneto mechanical systems |
US9715670B2 (en) | 2007-10-12 | 2017-07-25 | Oracle International Corporation | Industrial identify encoding and decoding language |
US7969348B2 (en) * | 2007-11-02 | 2011-06-28 | Recon Dynamics, Llc | Systems and methods for obtaining and using data from a localized location and telemetry system in a wide area location and telemetry system |
US9319756B2 (en) * | 2008-03-24 | 2016-04-19 | Intermec Ip Corp. | RFID tag communication triggered by sensed energy |
US8629576B2 (en) * | 2008-03-28 | 2014-01-14 | Qualcomm Incorporated | Tuning and gain control in electro-magnetic power systems |
US7852205B2 (en) * | 2008-04-10 | 2010-12-14 | Honeywell International Inc. | System and method for calibration of radio frequency location sensors |
US20090299918A1 (en) * | 2008-05-28 | 2009-12-03 | Nigelpower, Llc | Wireless delivery of power to a mobile powered device |
US8830062B2 (en) | 2008-06-05 | 2014-09-09 | Micron Technology, Inc. | Systems and methods to use radar in RFID systems |
US8242888B2 (en) | 2008-06-05 | 2012-08-14 | Keystone Technology Solutions, Llc | Systems and methods to determine motion parameters using RFID tags |
US8461966B2 (en) | 2008-06-05 | 2013-06-11 | Micron Technology, Inc. | Systems and methods to determine kinematical parameters using RFID tags |
US9256220B1 (en) * | 2008-06-25 | 2016-02-09 | The Boeing Company | System and method for monitoring completed manufacturing operations |
US20100007495A1 (en) * | 2008-07-10 | 2010-01-14 | International Business Machines Corporation | System and Method for Monitoring a Location of a Mobile RFID Reader |
CN102160293B (en) * | 2008-07-23 | 2013-12-04 | 恺悌科技私人有限公司 | A mthod and a system for determining the location of a subject, and a radio frequency identification tag assembly |
CN102150187A (en) * | 2008-07-30 | 2011-08-10 | 比特运输工具有限公司 | System and method for monitoring people and/or vehicles in urban environments |
US8090359B2 (en) | 2008-09-08 | 2012-01-03 | Proctor Jr James Arthur | Exchanging identifiers between wireless communication to determine further information to be exchanged or further services to be provided |
US8068012B2 (en) * | 2009-01-08 | 2011-11-29 | Intelleflex Corporation | RFID device and system for setting a level on an electronic device |
US20100201520A1 (en) * | 2009-02-12 | 2010-08-12 | Symbol Technologies, Inc. | System for determining item location based on feedback from fixed radio frequency identification (rfid) readers and/or fixed rfid beacon tags |
US8760262B2 (en) | 2009-03-20 | 2014-06-24 | Lutron Electronics Co., Inc. | Method of automatically programming a load control device using a remote identification tag |
US8797141B2 (en) * | 2009-08-20 | 2014-08-05 | Trimble Navigation Limited | Reverse RFID location system |
CN101694524B (en) * | 2009-10-21 | 2013-04-03 | 钟勇 | Accurate navigation system used for guiding indoor mall shopping, exhibition and sightseeing |
US8514069B2 (en) * | 2009-11-12 | 2013-08-20 | MTN Satellite Communications | Tracking passengers on cruise ships |
EP2341359B1 (en) * | 2009-12-22 | 2015-08-05 | 9Solutions Oy | Location tracking system |
US8723648B2 (en) * | 2009-12-30 | 2014-05-13 | Psion Inc. | Method and system for locating a hand-held terminal |
US20110199185A1 (en) * | 2010-02-12 | 2011-08-18 | Jeyhan Karaoguz | Building a location based service reference database based on encountered rfid tags |
US8381981B2 (en) * | 2010-05-03 | 2013-02-26 | Redwood Systems, Inc. | Radio frequency identification of lighting fixtures |
US8672222B2 (en) | 2010-05-03 | 2014-03-18 | Avery Dennison Corporation | Infrastructure-mounted RFID tags |
CN102312616B (en) * | 2010-06-29 | 2014-05-14 | 马瑞利汽车电子(广州)有限公司 | Method and system for passive entry and passive start |
US8816633B1 (en) * | 2010-07-12 | 2014-08-26 | The Boeing Company | Energy harvesting circuit |
DE102010031629B4 (en) * | 2010-07-21 | 2015-06-03 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | System and method for determining a position of a moving object, arrangement of general illumination LED and light sensor for a position determination of a moving object |
KR101277277B1 (en) * | 2010-12-31 | 2013-06-20 | 주식회사 케이티 | Method and apparatus for measuring location using access point and lamp |
US20120223819A1 (en) * | 2011-03-04 | 2012-09-06 | Bank Of America Corporation | Near Field Communication Event Attendee Tracking System |
CN103430512B (en) * | 2011-04-20 | 2016-12-21 | 索尼移动通信株式会社 | The method of anonymous tracking, server for object |
US9187993B2 (en) * | 2011-04-26 | 2015-11-17 | Saudi Arabian Oil Company | Methods of employing and using a hybrid transponder system for long-range sensing and 3D localizaton |
US9062539B2 (en) | 2011-04-26 | 2015-06-23 | Saudi Arabian Oil Company | Hybrid transponder system for long-range sensing and 3D localization |
US8811930B2 (en) * | 2011-06-30 | 2014-08-19 | Broadcom Corporation | Wireless peripheral device powered by harvested power generated by wireless communication |
US8694183B1 (en) * | 2011-12-06 | 2014-04-08 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Partial automated alignment and integration system |
KR20130082878A (en) * | 2011-12-21 | 2013-07-22 | 한국전자통신연구원 | Bio-signal transfer device, bio-signal monitoring system and method using thereof |
US8805423B2 (en) | 2012-06-19 | 2014-08-12 | Qualcomm Incorporated | Adaptive passive scanning and/or active probing techniques for mobile device positioning |
DE102012212856B4 (en) * | 2012-07-23 | 2014-11-06 | Siemens Aktiengesellschaft | Method and read / write device for detecting, selecting and reporting at least one of a plurality of contactless readable transponders |
TWI487931B (en) * | 2012-10-01 | 2015-06-11 | Internat Mobile Iot Corp | Earth positioning system |
US9244153B2 (en) * | 2012-10-31 | 2016-01-26 | Rockwell Automation Technologies, Inc. | Radio frequency identification in safety applications |
US9601267B2 (en) | 2013-07-03 | 2017-03-21 | Qualcomm Incorporated | Wireless power transmitter with a plurality of magnetic oscillators |
AT514618A1 (en) * | 2013-08-02 | 2015-02-15 | Siemens Ag | System for localizing objects |
US9495567B2 (en) | 2013-12-30 | 2016-11-15 | Verily Life Sciences Llc | Use of a tag and reader antenna for a simulated theremin effect |
CN103986952A (en) * | 2014-05-04 | 2014-08-13 | 苏州昭创光电技术有限公司 | Motion control system and method based on LED display |
US9797979B2 (en) | 2014-10-08 | 2017-10-24 | Symbol Technologies, Llc | System for and method of estimating bearings of radio frequency identification (RFID) tags that return RFID receive signals whose power is below a predetermined threshold |
WO2016163564A1 (en) * | 2015-04-09 | 2016-10-13 | 日本電気株式会社 | Information processing device, information processing system, position reporting method, and program recording medium |
US9472075B1 (en) | 2015-06-04 | 2016-10-18 | Tyco Fire & Security Gmbh | Systems and methods for locating items in a facility |
US10082797B2 (en) * | 2015-09-16 | 2018-09-25 | Ford Global Technologies, Llc | Vehicle radar perception and localization |
US10393852B2 (en) * | 2015-09-16 | 2019-08-27 | Here Global B.V. | Method and system of location estimation and navigation of autonomous vehicles |
WO2017061881A1 (en) * | 2015-10-07 | 2017-04-13 | New Bis Safe Luxco S.À R.L | Method, apparatus and system for location detection and object aggregation |
US10217318B2 (en) * | 2015-12-15 | 2019-02-26 | Igt Canada Solutions Ulc | Automated topology generation for electronic gaming machines |
KR102417610B1 (en) | 2016-03-03 | 2022-07-07 | 삼성전자주식회사 | Method and apparatus for reading code using short range mmwave radar |
US10333341B2 (en) | 2016-03-08 | 2019-06-25 | Ledvance Llc | LED lighting system with battery for demand management and emergency lighting |
GB2550108B (en) * | 2016-04-14 | 2019-11-06 | Paul Mccormack T/A Pactac | Radio locator system |
WO2017223420A1 (en) * | 2016-06-24 | 2017-12-28 | Crown Equipment Corporation | Indirect electronic badge tracking |
US9854398B1 (en) * | 2016-08-03 | 2017-12-26 | International Business Machines Corporation | System, method and recording medium for location verification |
DE102017100955A1 (en) * | 2017-01-18 | 2018-07-19 | Uctec Beteiligungsgesellschaft Ag | Arrangement and method for determining the location of a movable object |
EP3602830B1 (en) * | 2017-03-28 | 2021-06-23 | Qualcomm Incorporated | Range-based transmission parameter adjustment |
US10726218B2 (en) | 2017-07-27 | 2020-07-28 | Symbol Technologies, Llc | Method and apparatus for radio frequency identification (RFID) tag bearing estimation |
US10305611B1 (en) | 2018-03-28 | 2019-05-28 | Qualcomm Incorporated | Proximity detection using a hybrid transceiver |
US11590997B1 (en) | 2018-08-07 | 2023-02-28 | Staples, Inc. | Autonomous shopping cart |
US11084410B1 (en) | 2018-08-07 | 2021-08-10 | Staples, Inc. | Automated guided vehicle for transporting shelving units |
US11630447B1 (en) | 2018-08-10 | 2023-04-18 | Staples, Inc. | Automated guided vehicle for transporting objects |
WO2020070529A1 (en) * | 2018-10-05 | 2020-04-09 | Thomas Ralph | A method to enable autonomous guidance of vehicles |
US11180069B2 (en) | 2018-12-31 | 2021-11-23 | Staples, Inc. | Automated loading of delivery vehicles using automated guided vehicles |
US11119487B2 (en) | 2018-12-31 | 2021-09-14 | Staples, Inc. | Automated preparation of deliveries in delivery vehicles using automated guided vehicles |
US11124401B1 (en) | 2019-03-31 | 2021-09-21 | Staples, Inc. | Automated loading of delivery vehicles |
FR3097654B1 (en) * | 2019-06-21 | 2021-10-01 | Safran Electronics & Defense | METHOD AND DEVICE FOR LOCATING AN ELEMENT TRANSPORTABLE BY AN AIRCRAFT |
US11129116B2 (en) | 2019-06-21 | 2021-09-21 | Qualcomm Incorporated | System for detecting an object within a transmission path |
EP3798986A1 (en) * | 2019-09-27 | 2021-03-31 | Apple Inc. | Location aware visual markers |
JP6890352B1 (en) * | 2020-02-13 | 2021-06-18 | ユーピーアール株式会社 | Luggage management system |
FI129809B (en) * | 2021-08-10 | 2022-09-15 | Turck Vilant Systems Oy | A mobile device, a system, and a method for handling objects provided with radio frequency identifiers |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5260694A (en) * | 1992-01-10 | 1993-11-09 | Ndc Automation, Inc. | Automatic article tracking system for manually operated delivery system |
US5300875A (en) * | 1992-06-08 | 1994-04-05 | Micron Technology, Inc. | Passive (non-contact) recharging of secondary battery cell(s) powering RFID transponder tags |
US5646616A (en) * | 1994-07-01 | 1997-07-08 | Murata Kikai Kabushiki Kaisha | Picking system |
US6414626B1 (en) * | 1999-08-20 | 2002-07-02 | Micron Technology, Inc. | Interrogators, wireless communication systems, methods of operating an interrogator, methods of operating a wireless communication system, and methods of determining range of a remote communication device |
US6600418B2 (en) * | 2000-12-12 | 2003-07-29 | 3M Innovative Properties Company | Object tracking and management system and method using radio-frequency identification tags |
US6750769B1 (en) * | 2002-12-12 | 2004-06-15 | Sun Microsystems, Inc. | Method and apparatus for using RFID tags to determine the position of an object |
US6842121B1 (en) * | 1996-04-04 | 2005-01-11 | Micron Technology, Inc. | RF identification system for determining whether object has reached destination |
US6992581B2 (en) * | 2003-07-16 | 2006-01-31 | Dmatek Ltd. | Method and apparatus for attenuating of a broadcasting received signal for achieving a better distance resolution in monitoring systems |
US20060022038A1 (en) * | 2004-07-29 | 2006-02-02 | Hewlin Todd G | Mobile terminal finding system and method |
US7119738B2 (en) * | 2004-03-01 | 2006-10-10 | Symbol Technologies, Inc. | Object location system and method using RFID |
US7121467B2 (en) * | 2004-05-21 | 2006-10-17 | Intermec Ip Corp. | Indicators of optimum positioning of a data collection device for reading data carriers, such as RFID tags and machine-readable symbols |
US7151979B2 (en) * | 2002-11-26 | 2006-12-19 | International Paper Company | System and method for tracking inventory |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5796362A (en) * | 1994-06-13 | 1998-08-18 | Hittite Microwave Corporation | Post launch on-board identification friend or foe system |
US5917425A (en) * | 1996-01-22 | 1999-06-29 | Wireless Communiations Products, Llc | IR/RF locator |
US5974368A (en) * | 1997-08-29 | 1999-10-26 | Sarnoff Corporation | Remote vehicle data interface tag system |
CA2287286C (en) * | 1998-10-26 | 2009-01-27 | David A. Shaw | Interrogation, monitoring and data exchange using rfid tags |
US6396413B2 (en) * | 1999-03-11 | 2002-05-28 | Telephonics Corporation | Personal alarm monitor system |
US6868073B1 (en) * | 2000-06-06 | 2005-03-15 | Battelle Memorial Institute K1-53 | Distance/ranging by determination of RF phase delta |
US6542270B2 (en) * | 2000-12-08 | 2003-04-01 | Motorola, Inc. | Interference-robust coded-modulation scheme for optical communications and method for modulating illumination for optical communications |
US6865347B2 (en) * | 2001-01-05 | 2005-03-08 | Motorola, Inc. | Optically-based location system and method for determining a location at a structure |
US6922173B2 (en) * | 2002-02-05 | 2005-07-26 | Theodore R. Anderson | Reconfigurable scanner and RFID system using the scanner |
US6900762B2 (en) * | 2002-09-30 | 2005-05-31 | Lucent Technologies Inc. | Methods and apparatus for location determination based on dispersed radio frequency tags |
KR20050065194A (en) * | 2003-12-24 | 2005-06-29 | 한국전자통신연구원 | Ulid data structure and ulid-based location acquisition method and the lbs service system |
PL1577678T3 (en) * | 2004-03-09 | 2019-11-29 | Saab Ab | A system and method for determining the location of a moving object in a secluded space |
US7030761B2 (en) * | 2004-03-16 | 2006-04-18 | Symbol Technologies | Multi-resolution object location system and method |
-
2004
- 2004-09-29 US US10/954,967 patent/US7403120B2/en not_active Expired - Fee Related
-
2008
- 2008-03-18 US US12/050,784 patent/US20080157972A1/en not_active Abandoned
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5260694A (en) * | 1992-01-10 | 1993-11-09 | Ndc Automation, Inc. | Automatic article tracking system for manually operated delivery system |
US5300875A (en) * | 1992-06-08 | 1994-04-05 | Micron Technology, Inc. | Passive (non-contact) recharging of secondary battery cell(s) powering RFID transponder tags |
US5646616A (en) * | 1994-07-01 | 1997-07-08 | Murata Kikai Kabushiki Kaisha | Picking system |
US6842121B1 (en) * | 1996-04-04 | 2005-01-11 | Micron Technology, Inc. | RF identification system for determining whether object has reached destination |
US6414626B1 (en) * | 1999-08-20 | 2002-07-02 | Micron Technology, Inc. | Interrogators, wireless communication systems, methods of operating an interrogator, methods of operating a wireless communication system, and methods of determining range of a remote communication device |
US6600418B2 (en) * | 2000-12-12 | 2003-07-29 | 3M Innovative Properties Company | Object tracking and management system and method using radio-frequency identification tags |
US7151979B2 (en) * | 2002-11-26 | 2006-12-19 | International Paper Company | System and method for tracking inventory |
US6750769B1 (en) * | 2002-12-12 | 2004-06-15 | Sun Microsystems, Inc. | Method and apparatus for using RFID tags to determine the position of an object |
US6992581B2 (en) * | 2003-07-16 | 2006-01-31 | Dmatek Ltd. | Method and apparatus for attenuating of a broadcasting received signal for achieving a better distance resolution in monitoring systems |
US7119738B2 (en) * | 2004-03-01 | 2006-10-10 | Symbol Technologies, Inc. | Object location system and method using RFID |
US7121467B2 (en) * | 2004-05-21 | 2006-10-17 | Intermec Ip Corp. | Indicators of optimum positioning of a data collection device for reading data carriers, such as RFID tags and machine-readable symbols |
US20060022038A1 (en) * | 2004-07-29 | 2006-02-02 | Hewlin Todd G | Mobile terminal finding system and method |
Cited By (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8369866B2 (en) * | 2004-11-05 | 2013-02-05 | Wirelesswerx International, Inc. | Method and system for providing area specific messaging |
US20080220720A1 (en) * | 2004-11-05 | 2008-09-11 | Wirelesswerx International, Inc. | Method and system for providing area specific messaging |
US20080143546A1 (en) * | 2006-12-18 | 2008-06-19 | General Electric Company | Locating system and method |
US20080150696A1 (en) * | 2006-12-21 | 2008-06-26 | Bolander Jarie G | System for powering and reading RFID tags |
US7812725B2 (en) * | 2006-12-21 | 2010-10-12 | Tagent 6 Corporation | System for powering and reading RFID tags |
US20090212921A1 (en) * | 2008-02-25 | 2009-08-27 | Wirama Corporation | Localizing tagged assets using modulated backscatter |
US9262912B2 (en) | 2008-02-25 | 2016-02-16 | Checkpoint Systems, Inc. | Localizing tagged assets using modulated backscatter |
US20100117826A1 (en) * | 2008-11-11 | 2010-05-13 | Monster Medic, Inc. | Mobile monitoring and alert system |
US8085148B2 (en) * | 2008-11-11 | 2011-12-27 | Monster Medic, Inc. | Mobile monitoring and alert system |
US20110080264A1 (en) * | 2009-10-02 | 2011-04-07 | Checkpoint Systems, Inc. | Localizing Tagged Assets in a Configurable Monitoring Device System |
US9449202B2 (en) | 2009-10-02 | 2016-09-20 | Checkpoint Systems, Inc. | Localizing tagged assets in a configurable monitoring device system |
US8537007B2 (en) | 2010-04-08 | 2013-09-17 | Checkpoint Systems, Inc. | Autoaccreting database for EAS-RF applications |
CN101858974A (en) * | 2010-06-03 | 2010-10-13 | 清华大学 | Positioning system |
US20120026016A1 (en) * | 2010-07-27 | 2012-02-02 | The Boeing Company | Wireless Device Association System |
US8963691B1 (en) | 2010-07-27 | 2015-02-24 | The Boeing Company | Sensor association system using wireless device information |
US9113234B2 (en) * | 2010-07-27 | 2015-08-18 | The Boeing Company | Wireless device association system |
US11915567B2 (en) * | 2014-01-16 | 2024-02-27 | Automaton, Inc. | Systems and methods for RFID-based retail management |
US20210304576A1 (en) * | 2014-01-16 | 2021-09-30 | Automaton, Inc. | Systems and methods for rfid-based retail management |
WO2017095664A1 (en) * | 2015-11-30 | 2017-06-08 | Heraeus Noblelight America Llc | Lamps and light sources including rfid tags, and methods of assembling and operating the same |
US9978580B2 (en) | 2015-11-30 | 2018-05-22 | Heraeus Noblelight America Llc | Lamps and light sources including RFID tags, and methods of assembling and operating the same |
US10683171B2 (en) | 2016-09-30 | 2020-06-16 | Staples, Inc. | Hybrid modular storage fetching system |
US10803420B2 (en) | 2016-09-30 | 2020-10-13 | Staples, Inc. | Hybrid modular storage fetching system |
US11697554B2 (en) | 2016-09-30 | 2023-07-11 | Staples, Inc. | Hybrid modular storage fetching system |
US11702287B2 (en) | 2016-09-30 | 2023-07-18 | Staples, Inc. | Hybrid modular storage fetching system |
US11893535B2 (en) | 2016-09-30 | 2024-02-06 | Staples, Inc. | Hybrid modular storage fetching system |
US10589931B2 (en) | 2016-09-30 | 2020-03-17 | Staples, Inc. | Hybrid modular storage fetching system |
US10638404B1 (en) * | 2018-12-13 | 2020-04-28 | Securus Technologies, Inc. | Controlled-environment facility mobile device location tracking |
US10949730B2 (en) | 2019-02-15 | 2021-03-16 | International Business Machines Corporation | Leveraging channel diversity in wireless power and communication |
US10965166B2 (en) | 2019-02-15 | 2021-03-30 | International Business Machines Corporaton | Simultaneous wireless power transmission, communication, and localization |
US11238327B2 (en) | 2019-02-15 | 2022-02-01 | International Business Machines Corporation | Leveraging channel diversity in wireless power and communication |
Also Published As
Publication number | Publication date |
---|---|
US7403120B2 (en) | 2008-07-22 |
US20060071790A1 (en) | 2006-04-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7403120B2 (en) | Reverse infrastructure location system and method | |
US7142120B2 (en) | Item finding using RF signalling | |
US6738025B2 (en) | Antenna matching circuit | |
US20060022038A1 (en) | Mobile terminal finding system and method | |
US5936527A (en) | Method and apparatus for locating and tracking documents and other objects | |
US7423516B2 (en) | Systems and methods for approximating the location of an RFID tag | |
US6830181B1 (en) | Combined optical and radio frequency tag reader | |
US20060267772A1 (en) | Mode-diveristy RFAID tag and interrogator system and method for identifying an RFAID transponder | |
US20070247286A1 (en) | RFID tag receive signal strength indicator | |
US10930138B2 (en) | Apparatus and method for determining mounting state of a trailer tracking device | |
US20020011932A1 (en) | Object identification system with adaptive transceivers and methods of operation | |
JPH0974370A (en) | Radio frequency transponder | |
WO2008113104A1 (en) | Coarse and fine location for tagged items | |
US9626537B2 (en) | RFID system with distributed read structure | |
CN101809593A (en) | The signal line structure that is used for radio-frequency recognition system | |
KR20100080814A (en) | Extended rfid tag | |
EP1290618A2 (en) | Remote communication system | |
US10423809B2 (en) | Location sensing for analytical applications | |
US20130122813A1 (en) | Network node for a wireless sensor network | |
KR20200052745A (en) | Smart tag and object recognition system using the same | |
CN106407854B (en) | Middleware device, reader driving method, and tag misrecognition determination method | |
KR101872373B1 (en) | Goods release management system and method using beacon, recording medium for performing the method | |
EP2098979A1 (en) | Transponder system. | |
US6624785B2 (en) | Receiver designed to pick up an electromagnetic signal and system using such a receiver | |
EP3981225A1 (en) | Rfid integrated light infrastructure |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |