ASSET TRACKING SYSTEM FOR ELECTRONIC EQUIPMENT

• US 20090189767A1
• Filed: 01/29/2009
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Active Application

• Current Assignee: RF Code Incorporated
• Original Assignee: RF Code Incorporated
• Inventors: Graczyk, Ron, Medford, Mitchell, Gauer, Wilfried, Primm, Michael
• Application Number:
  US12/362,351
• Publication Number:
  US 20090189767A1
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G01S 2205/01 specially adapted for specific applications
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment

Abstract

An asset tracking system includes a server, a plurality of readers in communication with the server, and a plurality of radio frequency identification tags. Each of the plurality of readers is coupled to at least two antennas. The at least two antennas receive signals from a plurality of radio frequency identification tags.

Claims

1. A method of asset tracking, the method comprising:

receiving a first signal from a radio frequency identification tag via a first antenna, the first antenna extending along a dimension of an equipment rack, the first signal having a first strength;

receiving the second signal from the radio frequency identification tag via a second antenna, the second antenna extending parallel to the first antenna along the dimension of the equipment rack, the second signal having a second strength;

determining a location of the radio frequency identification tag based at least in part on the sum of the first and second strengths.

2. The method of claim 1, wherein the first antenna is oriented along a first side of the equipment rack.

3. The method of claim 1, wherein the second antenna is oriented along a second side of the equipment rack.

4. The method of claim 1, wherein the first antenna is shorter than the second antenna.

5. The method of claim 1, wherein the first antenna is asymmetrically disposed relative to the second antenna.

6. The method of claim 1, wherein determining the location includes applying a heuristic to the sum of the first and second strengths to determine a confidence level.

7. The method of claim 1, wherein determining the location includes applying the sum of the first and second strengths to a monotonic function to determine a confidence level.

8. The method of claim 7, wherein applying the sum of the first and second strengths to a monotonic function includes applying the sum of the first and second strengths to a cubic function.

9. The method of claim 1, further comprising delaying determination of the location by a fixed period starting when receiving the signal at the first antenna.

10. The method of claim 1, further comprising redetermining the location at a subsequent time based on a subsequently received first strength and using a value equal to the second strength when a subsequent second strength is not received.

11. The method of claim 1, further comprising redetermining the location at a subsequent time based on a subsequently received first strength and using a value based at least in part on the second strength when a subsequent second strength is not received.

12. The method of claim 11, wherein the value includes a moving average.

13. An identification tag comprising:

a flexible sheet having a first major surface and a second major surface;

an adhesive layer disposed on the first major surface of the flexible sheet proximal to a first end of the flexible sheet; and

an active radio frequency identification circuitry coupled to the flexible sheet at a second end of the flexible sheet.

14. The identification tag of claim 13, further comprising an identification number located proximal to the second end of the flexible sheet.

15. The identification tag of claim 14, wherein the identification number is encoded in a bar code.

16. The identification tag of claim 14, wherein the identification number is disposed on the first major surface of the flexible sheet.

17. The identification tag of claim 14, wherein the identification number is disposed on the second major surface of the flexible sheet.

18. The identification tag of claim 13, wherein the active radio frequency identification circuitry is coupled to the first major surface of the flexible sheet.

19. The identification tag of claim 13, wherein the active radio frequency identification circuitry is coupled to the second major surface of the flexible sheet.

20. The identification tag of claim 13, wherein the flexible sheet further comprises an intermediate portion between the first end and the second end, the intermediate portion being free of adhesive and unobstructed by the active radio frequency identification circuitry.

21. The identification tag of claim 13, wherein the flexible sheet forms a “

T”

shape at the first end.

22. An asset tracking system comprising:

a reader;

at least one antenna coupled to the reader and disposed along a dimension of an equipment rack; and

a radio frequency identification tag comprising;

a flexible sheet having a first major surface and a second major surface;

an adhesive layer disposed on the first major surface of the flexible sheet proximal to a first end of the flexible sheet; and

an active radio frequency identification circuitry coupled to the flexible sheet at a second end of the flexible sheet;

wherein the reader is to determine the location of the RFID tag relative to the equipment rack.

23. An asset tracking system comprising:

a reader;

a first antenna coupled to the reader and disposed along a dimension of an equipment rack proximal to a first side;

a second antenna coupled to the reader and disposed along the dimension of the equipment rack proximal to a second side; and

a radio frequency identification tag;

wherein the first antenna is to receive a first signal from the radio frequency identification tag via a first channel, the second antenna is to receive a second signal from the radio frequency identification tag via a second channel, the system to determine the location of the radio frequency identification tag based at least in part on the strength of the first and second signals.

24. The asset tracking system of claim 23, wherein the location of the radio frequency identification tag is determined based at least in part on the sum of the signal strength of the first and second signals received at the first and second antennas, respectively.

25. The asset tracking system of claim 23, wherein a confidence level is determined based at least in part on the strength of the signal received at the first and second antennas.

26. The asset tracking system of claim 23, wherein the first antenna is shorter than the second antenna.

27. The asset tracking system of claim 23, wherein the first antenna is asymmetrically disposed relative to the second antenna.