Dual mode tracking system
First Claim
1. A system for locating an object associated with a tag, comprising:
- a cell controller that includes a receiver for receiving a signal, the receiver having a receiving portion that receives the signal in a wireless form;
a first tag associated with said object that outputs the signal, said first tag having no active internal power source; and
an external power source that provides a wireless power source to the first tag, the external power source being physically separated from the receiving portion of the receiver so that the first tag would not be powered by the external power source if the external power source was located at the receiving portion.
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Accused Products
Abstract
System for tracking mobile tags. Cell controllers with multiple antenna modules generate a carrier signal which is received by the tags. Tags shift the frequency of the carrier signal, modulate an identification code onto it, and transmit the resulting tag signal at randomized intervals. The antennas receive and process the response, and determine the presence of the tags by proximity and triangulation. The recursive-least squares (RLS) technique is used in filtering received signals. Distance of a tag from an antenna is calculated by measuring the round trip signal time. The cell controllers send data from the antenna to a host computer. The host computer collects the data and resolves them into positional estimates. Data are archived in a data warehouse, such as an SQL Server. Also disclosed is an article tracking system that supports both active and passive tags with a cell controller able to read both passive and active tag signals.
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Citations
27 Claims
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1. A system for locating an object associated with a tag, comprising:
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a cell controller that includes a receiver for receiving a signal, the receiver having a receiving portion that receives the signal in a wireless form;
a first tag associated with said object that outputs the signal, said first tag having no active internal power source; and
an external power source that provides a wireless power source to the first tag, the external power source being physically separated from the receiving portion of the receiver so that the first tag would not be powered by the external power source if the external power source was located at the receiving portion. - View Dependent Claims (2, 3, 4, 5, 6, 7)
a quadrature modulator that extracts inphase and quadrature components of said signal; and
a digitizer that digitizes the inphase and quadrature components for subsequent processing.
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8. A method for locating an object, comprising:
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receiving a wireless source of power at a first tag associated with said object, the wireless source of power being emitted from an external power source location;
sending a wireless signal from the first tag; and
receiving said wireless signal at a reception location to determine a location of the object, the reception location being separated from the external power source location so that the first tag would not be powered by the wireless source of power if the external power source location was located at the reception location. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
providing a hybrid active/passive tag as the first tag.
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10. The method of claim 8, further comprising:
providing a passive tag as the first tag.
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11. The method of claim 10, further comprising:
providing an active tag as a second tag associated with a second object, the active tag capable of communication to identify the location of the second object.
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12. The method of claim 8, wherein the step of sending the wireless signal comprises transponding a received signal.
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13. The method of claim 8, further comprising:
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transmitting a first signal at a transmission location;
receiving said first signal at an active tag associated with a second object; and
transponding said first signal by the active tag.
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14. The method of claim 8, further comprising:
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associating a unique identifier with said first tag;
phase modulating said unique identifier onto said wireless signal; and
determining the distance of said first object by measuring the round trip time associated with a first signal being sent to the first tag and said wireless signal being received.
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15. The method claim 8, further comprising:
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extracting inphase and quadrature components of said wireless signal; and
digitizing the inphase and quadrature components for subsequent processing.
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16. A system for monitoring the location of objects, comprising:
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at least one cell controller unit connected to at least one transmission antenna for transmitting a cell controller signal modulated onto a carrier signal at a first frequency and at a selected transmission time, and connected to at least one reception antenna for receiving a responding tag signal containing a tag datagram at a second frequency and at a reception time;
at least one tag unit having a translation circuitry for translating each received cell controller signal into the tag signal, said at least one tag unit being a passive tag unit having no active internal power source for signal transmission;
at least one external power source that provides a wireless power source to the at least one tag unit, at least one external power source being physically separated from at least one reception antenna so that a tag unit that is powered by the external power source would not be so powered by the external power source if the external power source was located at the reception antenna that receives a responding tag signal from the tag unit; and
at least one calculation unit connected to each cell controller for calculating the location of each tag unit based on the reception time at least one reception antenna. - View Dependent Claims (17, 18, 19, 20, 21)
at least one active tag unit having an internal power source that is a low power battery, said at least one active tag unit being in a low power state between consecutive transmissions of a received cell controller signal.
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18. The system of claim 16, wherein said external power source is a wireless power source that includes one or more capacitors and one or more inductors.
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19. The system of claim 16, wherein said tag datagram includes error correction bits.
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20. The system of claim 16, wherein said tag datagram includes a validity check.
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21. The system of claim 16, wherein said tag datagram includes data derived from an object associated with said at least one tag unit.
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22. A system for locating an object, comprising:
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a first tag, to be associated with said object, that transmits a first signal at a first frequency, said first tag being adapted to operate as both a passive tag or an active tag, said first tag operating as a passive tag when receiving power from an external power source to transmit said first signal, and said first tag operating as an active tag when using power from an internal power source to transmit said first signal. - View Dependent Claims (23, 24, 25, 26, 27)
a cell controller that transmits an interrogation signal and includes a receiver for receiving the first signal, the receiver having a receiving portion that receives the first signal in a wireless form; and
an external power source that provides a wireless power source to the first tag, the external power source being physically separated from the receiving portion of the receiver so that the first tag would not be powered by the external power source if the external power source was located at the receiving portion.
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Specification