Identification and location of RF tagged articles

• US 7,528,721 B2
• Filed: 08/14/2006
• Issued: 05/05/2009
• Est. Priority Date: 08/14/2006
• Status: Expired due to Fees

• Current Assignee: Eduard Levin, Evgueni Rozoumovitch
• Original Assignee: Eduard Levin, Evgueni Rozoumovitch
• Inventors: Levin, Eduard, Rozoumovitch, Evgueni
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): Labbees; Edny
• Application Number:
  US11/502,673
• Publication Number:
  US 20080042838A1
• Time in Patent Office: 995 Days
• Field of Search: 3405721-5729, 340/10.1, 235375-385
• US Class Current: 340/572.1
• CPC Class Codes: G01S 1/54 Narrow-beam systems producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon; Overlapping broad beam systems defining a narrow zone and producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

The RFID system is for automatic recognition of one or all of a plurality of objects or articles located in an interrogation zone and having RFID tags mounted thereon. The tags have transponders carrying RFID information codes are sequentially and individually scanned with interrogation signals and activated to emit the information codes signals readable with a reader. The interrogation signals are based on the reader antennas and the configurations and locations of the tags. Signals returned from the transponders of the tags are processed to determine their electronic product code and location. The operation is repeated until the recognition and location of all tags in the entire interrogation zone are completed.

Claims

1. A method of identification and location of articles provided with RFID tags located in a plurality of interrogation zones with a reader, comprising:

selecting location and coordinates of a first interrogation zone of said plurality of interrogation zones by said reader;

selecting dimensions of said first interrogation zone;

dividing said first interrogation zone into a plurality of tag interrogation zones;

transmitting tag activation signals from a plurality of transmission antennas from a selected groups of said antennas and a number of antennas in each group of said groups of said antennas to tags located in a selected tag interrogation zone;

selecting a sequence of continuing activation of said tags in said selected tag interrogation zones;

selecting a start point of scanning of said selected tag interrogation zone by said reader;

calculating signal parameters for activation of said tags for each tag interrogation zone in said tag interrogation zones by each group of antennas of said groups of antennas depending on location of said selected tan interrogation zone, activation signal power and width of said tag activation signals required to activate said tans in each one of said plurality of tag interrogation zones;

calculating time required for scanning said each one of said tag interrogation zones by said reader;

creating signals for activating selected RFID tags in accordance with calculated signal parameters for said tag interrogation zone and each one of said antennas;

transmitting sequence of activation signals by transmitting separate signal by each one of said antennas and said each group of antennas for activating said selected RFID tags in said tag interrogation zone;

calculating time lapse between beginning of signal transmission for activating said selected RFID tags from a first group of said antennas and a selected present time coinciding with an end of signal transmission from a last antenna of said group of antennas assigned for activation of said selected REID tars;

comparing said time lapse with time of scanning in said tag interrogation zone;

shifting to another selected tau interrogation zone location when said time lapse is more tan said time of scanning of said tag interrogation zone;

receiving said activation signals for said selected RFID tags in said tag interrogation zone;

processing said activation signals for activating said selected RFID tags in said tag interrogation zone and making a selected tag to be activated;

transmitting a signal information from a transponder of an activated tag, receiving said signal information including tag information by said reader;

processing said signal information by said reader and reading said tag information;

creating a tag data consisting of tag coordinates, an electronic code, description of product whereon said tag is provided, and tag information data;

entering said tag information data in a RFID reader memory;

repeating above steps until scanning of each said tag interrogation zone has been completely accomplished;

organizing, storing and monitoring tag data including coordinates, electronic codes, description of articles bearing said tags, graphic view of said articles, security and service information data.

2. A method according to claim 1 wherein a number of operations of said tag interrogation zone is predetermined, and said scanning of said tag interrogation zone is repeated in accordance with said predetermined number of scanning operation.

3. A method according to claim 2 wherein said scanning of said tag interrogation zone is repeated by decreasing amplitude of said activation signals for a number of times according to a value optimizing probability of tag selection and detection, identification of electronic code and determination of tag location, until tag information signal is received by said reader.

4. A method according to claim 1 wherein said signals for activating said selected RFID tags are pulse train signals with RF carrier having amplitude shift keying and a number pulses predetermined according to parameters of said tag, said reader and said interrogation zone, and each pulse in said pulses being created as in phase summing of signals at said tag zone from signals at output of each antenna in each group of antennas.

5. An apparatus for identification and location of a plurality of RFID tags with a reader, comprising:

a plurality of antennas;

signaling means for defining activation signals operative for activating selected RFID tags, said signal means including selection means operative for selecting location and coordinates of an interrogation zone and establishing a start point of scanning of said interrogation zone by said reader,

first calculating means operative for calculating parameters of activation signals for actuating said selected RFID tags for each of said interrogation zone,

second calculating means being operative for determining length of dine of said scanning of said interrogation zone by said reader,

said first calculating means being operative for activating said selected RFID tags in said interrogation zone and to determine activation of a present tag being interrogated,

said second calculating means being operative for processing and reading information signals in response signals for reading tag information for said reader,

data generation means operative in response to said response signals for creating tag data including tag coordinates, electronic code of said tags, and description and related information of product bearing said tags,

recording means operative for entering said tag data into memory of said reader,

monitoring means operative for organizing, storing and monitoring said tag data, and

power supply means operative for providing said selected RFID tag with power supply,

comparison means operative for comparing time lapse from a beginning of sending said activation signals to a predetermined present time with time of said scanning, and being operative for shifting interrogation zone location to another tag zone when said time lapse is more than time of scanning of said tag interrogation zone.

repetition means operative for repeating above steps until scanning of the entirety of said interrogation zone by said reader.

6. An apparatus according to claim 5 including means with controlled directivity pattern for transmitting signals for activating said selected RFID tag.

7. An apparatus according to claim 5 including means with controlled directivity pattern for receiving said information signals by said reader.

8. An apparatus according to claim 5 including means for scanning said interrogation zone for a predetermined number of times with said activation signals.

9. An apparatus according to claim 5 including means operative for calculating dimensions of said interrogation zone, and means operative for controlling scanning of said interrogation zone within said dimensions.