Interrogation, monitoring and data exchange using RFID tags

• US 6,917,291 B2
• Filed: 02/26/2003
• Issued: 07/12/2005
• Est. Priority Date: 10/26/1998
• Status: Expired due to Term

• Current Assignee: Identec Solutions AG
• Original Assignee: Identec Solutions, Inc. (Identec Solutions AG)
• Inventors: Allen, Barry
• Primary Examiner(s): Pope, Daryl C
• Application Number:
  US10/373,175
• Publication Number:
  US 20030220711A1
• Time in Patent Office: 867 Days
• Field of Search: 340/10.1, 340/505, 340/539.1, 340/572.1, 340/825.69, 340/825.72
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• 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
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

A method and apparatus for identification and monitoring of, and obtaining data relating to, products moving along a distribution path, including at least one RFID tag mountable to a product, or product carrier, and a plurality of interrogators spaced apart along the distribution path, wherein each interrogator of the plurality of interrogators cooperates in RF communication with the RFID tag when the RFID tag is in proximity to the each interrogator along the distribution path. Each interrogator interrogates the RFID tag during the RF communication so as to obtain unique data, unique to the RFID tag. The RFID tag and each interrogator each includes a transceiver and memory.

Claims

1. An apparatus for identification and monitoring of, and obtaining data relating to, products moving through choke points along a distribution path, comprising:

an RFID tag mountable to a product, or product carrier,

at least two RF readers spaced apart on opposite upstream and downstream sides of each chock point of said choke points along said distribution path, wherein each RF reader of said at least two RF readers cooperates in RF communication with said RFID tag when said RFID tag is within a choke point zone containing at least one said choke point and said at least two RF readers, said apparatus further comprising a processor, said at least two RF readers also cooperate with said processor for the communication of data from said RFID tag to said processor,

wherein said each reader obtains said data and said data includes unique data, unique to said RFID tag, during said RF communication,

so that said unique data is communicated to said unique data to said processor,

and wherein said processor includes data processing means to;

a) monitor, as detected and read by said at least two RF readers, RF field strength data associated with said RFID tag during said RF communication in said read zone, and

b) determine estimated distances of said RFID tag from said at least two RF readers and estimated velocity of said RFID tag through said read zone.

2. The apparatus of claim 1 wherein said processor also includes data processing means for mapping of said estimated distances and said estimated velocity of said RFID tage when in said read zone.

3. The apparatus of claim 2 wherein said processor also includes data processing means for merging said field strength data in said read zone so as to include field strength data from said RFID tag in a further number of said choke points to map said RFID tage along said distribution path.

4. The apparatus of claim 1 further comprising means for selectively varying an RF power associated with said RF communication so as to selectively vary the size of said read zone.

5. The apparatus of claim 1 wherein said at least two RF readers broadcast during said RF communication by a spread spectrum transmission, and wherein said RFID tag broadcasts during said RF communication by a narrow band transmission, and wherein a transmission power level of said spread spectrum transmission is higher than a transmission power level of said narrow band transmission.

6. The apparatus of claim 5 wherein said transmission power level of said spread spectrum transmission is generally 4 watts.

7. The apparatus of claim 6 wherein said transmission power level of said narrow band transmission is generally one milliwatt.

8. A method for identification and monitoring of, and obtaining data relating to, products moving through choke points along a distribution path, comprising the steps of:

a) providing an RFID tag mountable to a product, or product carrier,

b) providing at least two RF readers spaced apart on opposite upstream and downstream sides of each chock point of said choke points along said distribution path, wherein each RF reader of said at least two RF readers cooperates in RF communication with said RFID tag when said RFID tag is within a choke point zone containing at least one said choke point and said at least two RF readers,

c) providing a processor, said at least two RF readers also cooperate with said processor for the communication of data from said RFID tag to said processor,

d) obtaining by said each reader said data and said data includes unique data, unique to said RFID tag, during said RF communication, so that said unique data is communicated to said unique data to said processor,

e) detecting and reading by said at least two RF readers of RF field strength of said RF communication by said RFID tag,

f) monitoring by data processing means in said processor of said RF field strength of said RFID tag during said RF communication in said read zone, and

g) determining estimated distances of said RFID tag from said at least two RF readers and estimated velocity of said RFID tag through said read zone.

9. The method of claim 8 further comprising the step of mapping, by said data processing means, of said estimated distances and said estimated velocity of said RFID tag when in said read zone.

10. The method of claim 9 further comprising the step of merging, by said data processing means of field strength data corresponding to said field strength in said read zone so as to include field strength data from said RFID tag in a further number of said choke points and mapping said RFID tag along said distribution path.

11. The method of claim 8 further comprising the steps of selectively varying an RF power associated with said RF communication so as to selectively vary the size of said read zone.

12. The method of claim 8 further comprising the step of broadcasting during said RF communication by said at least two RF readers using only a spread spectrum transmission, and broadcasting by said RFID tag during said RF communication using only a single narrow band transmission, and providing a transmission power level of said spread spectrum transmission which is higher than a transmission power level of said narrow band transmission.

13. The method of claim 12 wherein the provided transmission power level of said spread spectrum transmission is generally 4 watts.

14. The method of claim 13 wherein the provided transmission power level of said narrow band transmission is generally one milliwatt.