Active Virtual Fence Using Mesh Networked RF Tags

• US 20150137971A1
• Filed: 10/20/2014
• Published: 05/21/2015
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Zebra Enterprise Solutions Corp. (Zebra Technologies Corporation)
• Inventors: Raphaeli, Dan
• Granted Patent: US 9,454,885 B2
• Time in Patent Office: Days
• US Class Current: 340/539.13
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G08B 13/2494 by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means

Abstract

A system capable of monitoring an area and detecting a disturbance with the area. The system has a plurality of ultra-wide band radio frequency tags, each of the tags including a digital signal processing module configured to monitor changes in radio frequency multipath properties of received packets transmitted by at least one other of the tags. Changes in the radio frequency multipath properties may be caused by a disturbance indicative of an object in the vicinity of the tags. A corresponding method is also disclosed.

Claims

1. A system capable of monitoring an area and detecting a disturbance with the area, the system comprising a plurality of ultra-wide band radio frequency tags, each of said plurality of tags communicating with one or more neighboring tags, and at least one of said plurality of tags including a digital signal processing module configured to monitor changes in radio frequency multipath properties of received packets transmitted by at least one other of said one or more neighboring tags, said changes being caused by a disturbance indicative of an object in the vicinity of the tags.

2. The system of claim 1, wherein at least one from the group including at least one of said tags, at least one reader operatively associated with said plurality of tags, and a central processor operatively associated with either said reader or said at least one tag, includes a pattern recognition module which classifies the object and determines a location of the object causing said disturbance based on said processes changes in radio frequency multipath properties.

3. The system of claim 2, wherein at least said central processor is configured to provide information to a user regarding said disturbance.

4. The system of claim 1 wherein a mesh network formed between at least some of said plurality of tags.

5. The system of claim 4 wherein said mesh network includes at least one of a reader and a central processor operatively associated with said mesh network.

11. The system of claim 1 further comprising each of the plurality of tags configured to transmit data regarding one or more multipath components upon detecting one or more changes in radio frequency multipath properties of received packets.

13. The system of claim 1 further comprising each of the plurality of tags configured to transmit the changes in radio frequency multipath properties of received packets to a reader or a central processor associated with the plurality of tags;

the reader or the central processor configured to;

determine changes in a multipath pattern associated with the plurality of tags based on the changes in radio frequency multipath properties; and

determine characteristics of the object causing the changes in the multipath pattern.

6. A method for detecting the entry of an object into a monitored area, the method comprising:

deploying a plurality of ultra-wide band radio frequency tags, each of said plurality of tags communicating with one or more neighboring tags and at least one of said plurality of tags including a digital signal processing module configured to monitor changes in radio frequency multipath properties;

monitoring, by at least one said tag, radio frequency multipath properties of received packets transmitted by at least one other of said one or more neigh boring tags; and

determining if any changes in said frequency multipath properties have occurred.

7. The method of claim 6 further comprising classifying and determining a location of a disturbance causing said any changes in said frequency multipath properties using a pattern recognition module operatively associated with any one of at least one of said tags, a reader, and a central processor each operatively associated with a mesh network.

8. The method of claim 7, wherein said determining a location of a disturbance causing said any changes, in said frequency multipath properties is implemented using said frequency multipath properties from as few as two said tags.

9. The method of claim 6, further comprising forming a mesh network between at least some of said plurality of tags.

10. The method of claim 8, further comprising operatively associating at least one of;

a reader and a central processor with said mesh network.

12. The method of claim 6 further comprising transmitting, by at least one said tag, data regarding one or more multipath components upon determining one or more changes in radio frequency multipath properties of received packets.

14. The method of claim 6 further comprising:

transmitting, by each of the plurality of tags, the changes in radio frequency multipath properties of received packets to a reader or a central processor associated with the plurality of tags;

determining, by the reader or the central processor, changes in a multipath pattern associated with the plurality of tags based on the changes in radio frequency multipath properties; and

determining characteristics of the object causing the changes in the multipath pattern.