METHOD AND APPARATUS FOR LOCATING ITEMS

• US 20100188211A1
• Filed: 01/27/2009
• Published: 07/29/2010
• Est. Priority Date: 01/27/2009
• Status: Active Grant

• Current Assignee: RadioFIDO LLC
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Rossman, Court E., Brommer, Karl D., Gili, Paul E., Logan, Cedric L.
• Granted Patent: US 8,044,797 B2
• Time in Patent Office: Days
• US Class Current: 340/539.320
• 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 19/0675 the resonating marks being of the surface acoustic wave [SAW] kind SAW devices per se H03H9/64

Abstract

A convenient handheld locator is provided for locating an item in an urban environment in which the locator is programmed to search for and locate specific items, with the detected item being displayed on the locator as to its identity or name, also displaying where the item is relative to the locator, as to position and range.

Claims

1. A system for locating an item in an urban environment, comprising:

an RFID tag on an item which upon interrogation with an interrogation beam emits a coded signal indicative of item back to a locator;

a locator having a data entry device;

a display on said locator;

a directional antenna carried by said locator;

a transmitter in said locator for projecting an interrogating beam using said directional antenna; and

,

a receiver and processor for detecting modulated backscatter return from a tagged item and for indicating on said display the identification of the item detected.

2. The system of claim 1, and further including:

a computer for registering items, the code associated therewith and the name of the item in a computer listing; and

,

a channel for uploading said listing to said locator and for storing said listing in said locator, whereby said data in said locator can be used to identify the item sought by its name such that only the item sought backscatters information back to the locator, and such that only the names of a selected item is displayed

3. The system of claim 2, wherein the selection of an item results in an interrogation beam coded with the code associated with the selected item, whereby the range of said system is increased due to a reduction in the signal-to-noise ratio.

4. The system of claim 3, and further including a processor within said locator for displaying the name of the detected item upon detection of the item.

5. The system of claim 1, wherein said display includes indicia indicating the position of the beam projected by said locator and an icon indicating the location of a detected item.

6. The system of claim 5, said location includes range from said locator to said item.

7. The system of claim 6, wherein said range is derived from a cross ambiguity function.

8. The system of claim 6, wherein said beam is pulsed and said range is derived from range gating on the pulses projected by said locator.

9. The system of claim 1, wherein said tag includes a SAW device having an impulse characteristic which provides a code that identifies of the tag and thus the item to which it is attached.

10. The system of claim 1, wherein said beam is modulated by the code associated with the tag of the sought-after item.

11. The system of claim 1, wherein said beam is unmodulated.

12. The system of claim 1, wherein the output power of said transmitter is variable.

13. The system of claim 1, wherein said tag includes a non-linear element.

14. The system of claim 13, wherein said non-linear element includes a diode.

15. The system of claim 14, wherein upon incident energy from said beam having a first frequency, said diode provides an output at twice said first frequency.

16. The system if claim 1, wherein said tag includes a pair of antennas including a receive antenna and a transmit antenna.

17. The system of claim 16, wherein said tag further includes a SAW device coupled between said receive antenna and said transmit antenna.

18. The system of claim 1, wherein said tag includes a receive antenna and a transmit antenna, and further including a diode coupled across said receive antenna and a SAW device coupled between said diode and said transmit antenna.

19. The system of claim 1, wherein said tag includes a receive antenna, a transmit antenna and a diode coupled between said antennas, and further including a battery to bias said diode, whereby the range of said system is increased over that is associated with an unbiased diode.

20. The system of claim 19, wherein said range increase is at least a 50% increase over that associated with an unbiased diode.

21. A method for locating a pre-determined object in an urban environment, comprising the step of:

tagging a pre-determined object with a tag that radiates a signal having a unique code responsive to interrogating beams and providing an interrogating beam from a locator.

22. The method of claim 21, and further including providing a computer listing of a number of tags and the item associated with the tag, along with the name of the associated item, and uploading the listing to the locator.

23. The method of claim 22, and further including having the locator generate the interrogating beam modulated with the code associated with the name of the item sought as uploaded from the computer.

28. The method of claim 22, wherein the range improvement through the use of battery biasing the diode is at least 50% over an unbiased diode.

24. A method for location an item in an urban environment, compromising the steps of:

providing a convenient handheld locator in which the locator is programmed to search for and locate a specific item; and

,

providing the locator with a display that displays the name of the item when the located item is detected.

25. The method of claim 24, and further providing the display with indicia indicating the location of the detected item.

26. The method of claim 24, further including a data input device on the locator and further including step of selecting from the data input device the name of the sought-after item.

27. A method for extending the range of an RFID system which employs a transmitter for transmitting an interrogation beam towards an RFID tag and an RFID tag that uses a non-linear element including a diode for extracting the energy from the interrogation beam and backscatters a coded signal, comprising the step of biasing the diode with a battery, whereby the range of the RFID system is improved over an unbiased diode.

29. The method of claim 27, wherein the RFID system includes a transmit antenna and a tag having a SAW device that has an impulse characteristic which codes the output of the tag, and wherein the SAW device is coupled between the diode and the transmit antenna for the tag.

30. The method of claim 27, wherein the diode biasing improves the harmonic response of the diode.

31. The method of claim 27, wherein the step of battery biasing the diode includes utilizing a lithium ion battery.

32. The method of claim 31, wherein the battery is a thin film battery.

33. The method of claim 27, wherein the battery includes a lithium battery having silicon nano wire anodes.

34. A method for extending the range of a parasitically-powered regenerative tag that includes a number of diodes in a diode rectifier circuit used to rectify incoming RF energy from an interrogation beam, comprising the step of:

battery biasing one or more of the diodes in the rectifier circuit to improve the efficiency of the diode circuit and to extend the range of the tag over that of a tag having unbiased diodes.

35. The method of claim 34, wherein the range extension is 10×

over that of a tag having unbiased diodes.

36. The method of claim 34, wherein said diodes are in a rectenna circuit.

37. The method of claim 36, wherein the rectenna circuit is coupled to an energy storage element and wherein the energy storage element is coupled to a transmitter.

38. The method of claim 37, and further including the step of:

providing a hysteretic switch between the energy storage element and the transmitter, and wherein the hysteretic switch couples the output of the energy storage element to the transmitter upon an output from a nanowatt comparator.

39. The method of claim 34, wherein the transmitter includes a diode oscillator circuit and wherein the frequency to which the output of the transmitter is tuned is determined by an LC circuit coupled to the diode.