Wireless locating and tracking systems

• US 7,084,740 B2
• Filed: 10/05/2005
• Issued: 08/01/2006
• Est. Priority Date: 06/07/2000
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bridgelall, Raj
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US11/244,920
• Publication Number:
  US 20060033609A1
• Time in Patent Office: 300 Days
• Field of Search: 340/10.42, 340/825.49, 340/539.13, 340/572.1, 340/572.7, 340/572.5, 340/539.1, 340/539.12, 342/44, 342/45, 342/42, 342/51
• US Class Current: 340/10.42
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 3/247 by switching different parts of a primary active element

Abstract

A locating and tracking system is provided in which the assets are desired to be located and tracked are associated with either radio frequency (RF) tags or radio frequency identification and radio frequency data communication (RFID/RFDC) devices. Depending on which device is attached to the asset, the other device is located at known locations. The RFID/RFDC devices interrogate and receive signals from the RF tags. The received information is sent to the host computer. With the location of either the RF tags or the RFID/RFDC devices known, the assets may be located and tracked. An improved RF tag antenna design is also provided by using a switching mechanism connected to at least two antennas.

Claims

1. A switched radio frequency identification (RFID) tag comprising:

a flexible substrate having a first region and a second region, wherein said first and second regions are substantially planar, and wherein said second region is adjacent said first region;

a first RFID antenna formed in said first region of said flexible substrate and having a first maximum directionality;

a second RFID antenna formed in said second region of said flexible substrate and having a second maximum directionality, wherein said second region of said substrate is configured to fold along a line between said first and second regions such that said first maximum directionality is substantially orthogonal to said second maximum directionality; and

a switching mechanism coupled to said first RFID antenna and said second RFID antenna, wherein said switching mechanism is configured to receive a remote signal emitted by a RFID/radio frequency data communication (RFDC) device (RFID/RFDC device) and to selectively switch between said first RFID antenna and said second RFID antenna in response to said remote signal.

2. The RFID tag of claim 1 wherein the remote signal is an ultra-sonic signal.

3. The RFID tag of claim 1 wherein the remote signal is a wireless signal.

4. The RFID tag of claim 1, said RFID tag further comprising a third RFID antenna formed in a third region of said flexible substrate and having a third maximum directionality, wherein said switching mechanism is further configured to selectively switch between said first, second, and third RFID antennas in response to said remote signal, and wherein said third region of said flexible substrate is configured to fold along a line between said third region and said first region such that said first, second, and third maximum directionalities are substantially orthogonal to each other.

5. A system for determining inventory in a section of a warehouse, comprising:

a plurality of locator tags associated with the inventory, the plurality of locator tags comprising;

a flexible substrate having a first region and a second region, wherein said first and second regions are substantially planar, and wherein said second region is adjacent said first region;

a first RFID antenna formed in said first region of said flexible substrate and having a first maximum directionality;

a second RFID antenna formed in said second region of said flexible substrate and having a second maximum directionality, wherein said second region of said substrate is configured to fold along a line between said first and second regions such that said first maximum directionality is substantially orthogonal to said second maximum directionality; and

a switching mechanism coupled to said first RFID antenna and said second RFID antenna, wherein said switching mechanism is configured to receive a remote signal emitted by a RFID/radio frequency data communication (RFDC) device (RFID/RFDC device) and to selectively switch between said first RFID antenna and said second RFID antenna in response to said remote signal;

a plurality of radio frequency identification/radio frequency data communication (RFID/RFDC) devices located in the section of the warehouse, wherein the RFID/RFDC devices;

poll the plurality of locator tags by sending a first plurality of interrogation signals to the plurality of locator tags at a first time;

receive a first plurality of return signals from the plurality of locator tags;

send the wireless signals to activate the switching mechanism;

process the first plurality of return signals from the plurality of locator tags to determine a first identity of the plurality of locator tags that are in range of the RFID/RFDC devices at the first time;

poll the plurality of locator tags by sending a second plurality of interrogation signals to the plurality of locator tags at a second time;

receive a second plurality of return signals from the plurality of locator tags;

process the second plurality of return signals from the plurality of locator tags to determine a second identity of the plurality of locator tags that are in range of the RFID/RFDC devices at the second time; and

a host computer system that receives the first identity of the plurality of locator tags that are in range of the RFID/RFDC devices at the first time and the second identity of the plurality of locator tags that are in range of the RFID/RFDC devices at the second time to determines the inventory of the section of the warehouse.

6. A corner-mountable RFID tag comprising:

a flexible substrate having a first region, a second region, and a third region, wherein each of said first, second, and third regions are substantially planar, and wherein said second and third regions are configured to fold with respect to said first region to form a structure capable of being embedded in the corner of a rectilinear asset;

a first RFID antenna formed in said first region of said flexible substrate and having a first maximum directionality;

a second RFID antenna formed in said second region of said flexible substrate and having a second maximum directionality;

a third RFID antenna formed in said third region of said flexible substrate and having a third maximum directionality, wherein said first, second, and third maximum directionalities are substantially orthogonal to each other;

a switching mechanism coupled to said first, second, and third RFID antennas, wherein said switching mechanism is configured to receive a remote signal emitted by a RFID/radio frequency data communication (RFDC) device (RFID/RFDC device) and to selectively switch between said first, second, and RFID antennas in response to said remote signal.

7. A method of forming an RFID tag, comprising the steps of:

providing a flexible substrate having a first region and a second region, wherein said first and second regions are substantially planar, and wherein said second region is adjacent said first region;

forming a first RFID antenna in said first region of said flexible substrate, wherein said first RFID antenna has a first maximum directionality;

forming a second RFID antenna in said second region of said flexible substrate, wherein said second RFID antenna has a second maximum directionality,

folding said first region with respect to said second region along a line between said first and second regions such that said first maximum directionality is substantially orthogonal to said second maximum directionality;

forming a switching mechanism on said flexible substrate such that said switching mechanism is coupled to said first RFID antenna and said second RFID antenna, and wherein said switching mechanism is configured to receive a remote signal emitted by a RFID/radio frequency data communication (RFDC) device (RFID/RFDC device) and to selectively switch between said first RFID antenna and said second RFID antenna in response to said remote signal.

8. The method of claim 7, further comprising the step of forming a third RFID antenna in a third region of said flexible substrate, wherein said third RFID antenna has a third maximum directionality, wherein said switching mechanism is further configured to selectively switch between said first, second, and third RFID antennas in response to said remote signal, further including the step of folding said third region of said flexible substrate along a line between said third region and said first region such that said first, second, and third maximum directionalities are substantially orthogonal to each other.