System and method for identifying objects using single connection line

• US 6,655,582 B2
• Filed: 01/02/2002
• Issued: 12/02/2003
• Est. Priority Date: 01/02/2001
• Status: Expired due to Term

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Wherenet Corporation (Zebra Technologies Corporation)
• Inventors: Wohl, Michael A., Boyd, Robert W.
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US10/038,532
• Publication Number:
  US 20020104879A1
• Time in Patent Office: 699 Days
• Field of Search: 235/380, 235/375, 235/492, 235/383, 235/385, 235/382, 235/382.5, 340/825.36, 340/825.49
• US Class Current: 235/380
• CPC Class Codes: G06K 17/00 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
• 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

A system and method for identifying objects within a monitored environment includes a plurality of tag signal readers contained within the monitored environment and serially connected along a single connection line as a coaxial cable for receiving tag signals from at least one tag contained within the monitored environment. The tagged signals received by tag signal readers are timed and associated with a particular tag signal reader, such as by the use of multiplexing techniques. A location processor is connected to the single connection line and determines which tag signals are first-to-arrive signals and conduct differentiation of the first-to-arrive signals to locate a tag.

Claims

1. A system for identifying objects within a monitored environment comprising:

a plurality of tag signal readers contained within the monitored environment and serially connected along a single connection line for receiving tag signals from at least one tag contained within the monitored environment, wherein the tag signals received by tag signal readers are timed and associated with a particular tag emission reader; and

a location processor connected to the single connection line for determining which tag signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a tag.

2. A system according to claim 1, wherein the single, connection line comprises a single, coaxial cable.

3. A system according to claim 1, wherein the tag signals comprise pseudo random spread spectrum radio frequency signals.

4. A system according to claim 1, wherein said location processor comprises a matched filter correlator having a plurality of matched filter banks containing parallel correlators.

5. A system according to claim 1, wherein said tag comprises a mobile device.

6. A system for identifying objects within a multistory building comprising:

a plurality of vertically separated tag signal readers positioned at a corner on each floor of the multistory building and serially connected along a single connection line extending vertically and connecting tag signal readers at a corner for receiving tag signals from at least one tag contained within the multistory building, wherein the tag signals received by tag signal readers are timed and associated with a particular tag signal reader positioned at a corner; and

a location processor connected to the single connection line for determining which tag signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a tag within the multistory building.

7. A system according to claim 6, wherein said multistory building comprises four corners per floor and a respective tag signal reader is positioned at each corner and vertically connected to any tag signal readers positioned immediately above and below.

8. A system according to claim 6, wherein the single, connection line comprises a single, coaxial cable.

9. A system according to claim 6, wherein the tag signals comprise pseudo random spread spectrum radio frequency signals.

10. A system according to claim 6, wherein said location processor comprises a matched filter correlator having a plurality of matched filter banks containing parallel correlators.

11. A system according to claim 6, wherein said tag comprises a mobile device.

12. A method of identifying objects within a monitored environment comprising the steps of:

generating tag signals from at least one tag within the monitored environment;

receiving tag signals within tag signal readers that are serially connected along a single connection line such that the tag signals received by tag signal readers are timed and associated with a particular tag signal reader; and

processing the tag signals within a location processor connected to the single connection line to determine which tag signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a tag.

13. A method according to claim 12, wherein the single connection line comprises a single, coaxial cable.

14. A method according to claim 12, and further comprising the step of transmitting the tag signals as pseudo random spread spectrum radio frequency signals.

15. A method according to claim 12, and further comprising the step of processing the pseudo random spread spectrum radio frequency signals by a matched filter correlator having a plurality of matched filter banks containing parallel correlators.

16. A method according to claim 12, wherein a tag comprises a mobile device.

17. A method of identifying objects within a monitored environment of a multistory building comprising the steps of:

generating tag signals from at least one tag within the multistory building;

receiving tag signals within vertically separated tag signal readers that are serially connected along a single connection line such that the tag signals are timed and associated with a particular tag signal reader, wherein a tag signal reader is positioned at each corner of a floor and connected vertically with a tag signal reader positioned at a corner directly above and below the floor; and

processing the tag signals within a location processor connected to the single connection line to determine which tag signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a tag.

18. A method according to claim 17, wherein the single connection line comprises a single, coaxial cable.

19. A method according to claim 17, and further comprising the step of transmitting the tag signals as pseudo random spread spectrum radio frequency signals.

20. A method according to claim 17, and further comprising the step of processing the pseudo random spread spectrum radio frequency signals by a matched filter correlator having a plurality of matched filter banks containing parallel correlators.

21. A method according to claim 17, wherein a tag comprises a mobile device.

22. A method according to claim 17, wherein said multistory building comprises four corners per floor and a respective tag signal reader positioned at each corner and vertically connected to only tag signal readers positioned immediately above and below.