Systems and methods for providing geolocation using wireless signals

• US 8,416,134 B2
• Filed: 12/01/2009
• Issued: 04/09/2013
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Kim, Byoung-Jo, Rice, Christopher, Henry, Paul
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US12/628,965
• Publication Number:
  US 20110129022A1
• Time in Patent Office: 1,225 Days
• Field of Search: 342/387, 342463-464
• US Class Current: 342/464
• CPC Class Codes: G01S 5/02528 Simulating radio frequency fingerprints
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

A system for determining a location of a receiver is disclosed. The system includes at least one transmitter transmitting one or more radio signals, respectively. The system also includes a receiver comprising a clock, a memory, and a processor configured to execute computer-executable instructions stored in the memory. The instructions makes the receiver operable to receive the radio signals, capture the radio signals as one or more received signal waveform, respectively, and store the received signal waveforms in the memory. The instructions also make the receiver operable to calculate one or more virtual transmitted waveforms based upon the received signal waveforms, respectively and determine, based upon the received signal waveforms and the virtual transmitted waveforms, a position of the receiver relative to the transmitters.

Claims

1. A system, for determining a location of a receiver, comprising:

a transmitter configured to transmit a radio signal;

a receiver communicatively linked to the transmitter, the receiver comprising a clock, a processor and a memory having stored thereon computer-executable instructions that, when executed by the processor, cause the processor to perform a method comprising;

receiving the radio signal;

capturing the radio signal as a received signal waveform;

storing the received signal waveform in the memory;

calculating a virtual transmitted waveform based upon the received signal waveform; and

determining, based upon the received signal waveform and the virtual transmitted waveform, a position of the receiver relative to the transmitter.

2. The system of claim 1, wherein the computer-executable instructions that, when executed by the processor, cause the processor to determine the position of the receiver relative to the transmitter, causes the processor to determine the position of the receiver based on the waveforms and transmission timing information regarding the transmitter.

3. The system of claim 2, wherein:

the transmitter is configured to transmit the signal includes a first transmitter configured to transmit a first radio signal, a second transmitter configured to transmit a second radio signal, and a third transmitter configured to transmit a third radio signal;

the computer-readable instructions, when executed by the processor, cause the processor to;

receive the first radio signal, the second radio signal, and the third radio signal;

perform the receiving, the capturing, the storing, and the calculating with respect to each of the first radio signal, the second radio signal, and the third radio signal; and

in determining the position of the receiver relative to the transmitter, determine the position of the receiver relative to the first transmitter, the second transmitter, and the third transmitter.

4. The system of claim 2, wherein:

the receiver comprises a virtual transmitter module configured to calculate the virtual transmitted waveform including generating a virtual transmitted data stream; and

the virtual transmitted data stream is substantially identical to a transmitted data stream associated with the radio signal transmitted by the transmitter.

5. The system of claim 4, wherein the virtual transmitter module is further configured to virtually transmit the virtual transmitted data stream to obtain a virtual transmitted signal waveform.

6. The system of claim 5, wherein the receiver further comprises a time shift determiner configured to compare the virtual transmitted signal waveform to a received signal waveform to determine a time shift required to align the virtual transmitted signal waveform to the received signal waveform.

7. The system of claim 6, wherein the computer-readable instructions, when executed by the processor, further cause the processor to determine the position of the receiver relative to the transmitter based on the time shift.

8. The system of claim 7, wherein the computer-readable instructions, when executed by the processor, further cause the processor to:

obtain transmitter location data for the transmitter; and

determine the location of the receiver based upon the transmitter location data for the transmitter and the position of the receiver relative to the transmitter.

9. The system of claim 4, wherein the virtual transmitter module comprises a data stream determination application, wherein:

the data stream determination application applies a fast Fourier transform algorithm to the received signal waveform to create corresponding data output; and

the data stream determination application transmits the data output to an orthogonal frequency-division multiplexing demodulator to generate corresponding virtual transmitted data stream.

10. The system of claim 9, wherein the virtual transmitter module comprises a virtual transmitter application, wherein:

the virtual transmitter application receives the virtual transmitted data stream;

the virtual transmitter application transmits the virtual transmitted data stream to an orthogonal frequency-division multiplexing modulator to generate corresponding modulated data stream; and

the virtual transmitter application applies an inverse fast Fourier transform algorithm to the modulated data stream to generate corresponding virtual transmitted signal waveform.

11. The system of claim 10, wherein the computer-readable instructions, when executed by the processor, further cause the processor to store the virtual transmitted signal waveform at the memory.

12. A method, for determining location of a receiver using a radio signal, comprising:

transmitting from the transmitter, a signal;

receiving the radio signal at a receiver in communication with the transmitter;

capturing the radio signal, at the receiver, as a received signal waveform;

storing, at a memory device associated with the receiver, the received signal waveform;

calculating, at the receiver, a virtual transmitted signal waveform wherein the virtual transmitted signal waveform is calculated based upon the received signal waveform; and

determining, at the receiver, a position of the receiver relative to the transmitter based upon the received signal waveform and the virtual transmitted signal waveform.

13. The method of claim 12, wherein determining the position of the receiver relative to the transmitter is based on the waveforms and transmission timing information regarding the transmitter.

14. The method of claim 13, wherein calculating the virtual transmitted signal waveform includes:

generating a data stream at a virtual transmitter module of the receiver, the data stream being substantially identical to a transmitted data stream including the radio signal transmitted by the transmitter; and

virtually transmitting the data stream to obtain the virtual transmitted signal waveform.

15. The method of claim 14, further comprising:

determining a time difference with respect to the signal corresponding to the transmitter including;

comparing, at a time shift determiner associated with the receiver, the virtual transmitted signal waveform to the received signal waveform;

determining, at the time shift determiner, the time difference being the time shift required to align the virtual transmitted signal waveform to the received signal waveform;

obtaining transmitter location data for the transmitter; and

determining the location of the receiver based upon the transmitter location data for the transmitter and the position of the receiver relative to the transmitter.

16. The method of claim 15, further comprising, for the received radio signal:

applying a fast Fourier transform algorithm to the received signal waveform to create a data output;

transmitting the data output to an orthogonal frequency-division multiplexing demodulator to generate a virtual transmitted data stream;

transmitting the virtual transmitted data stream to an orthogonal frequency-division multiplexing modulator to generate a modulated data stream;

applying an inverse fast Fourier transform algorithm to the modulated data stream to generate the virtual transmitted signal waveform; and

storing the virtual transmitted signal waveform at the memory.

17. A non-transitory computer readable medium having stored thereon computer readable instructions that, when executed by a processor, cause the processor to perform a method comprising:

receiving a radio signal, the radio signal being transmitted by a transmitter in communication with a receiver;

capturing the radio signal received as a received signal waveform;

storing the received signal waveform at a memory device associated with the receiver;

obtaining virtual transmitted waveform based upon the radio signal received from the transmitter; and

determining a position of the receiver relative to the transmitter based upon the received signal waveform and the virtual transmitted waveform.

18. The computer readable medium of claim 17, wherein the computer readable instructions, when executed by the processor, further cause the processor to perform operations comprising:

generating a data stream at a virtual transmitter module associated with the receiver, the data stream being substantially identical to the data stream transmitted by the transmitter;

virtually transmitting the data stream at the virtual transmitter module associated with the receiver to obtain the respective virtual transmitted signal waveform;

obtaining transmitter location data for the transmitter; and

determining the location of the receiver based upon the transmitter location data for the transmitter and the position of the receiver relative to the transmitter.

19. The computer readable medium of claim 18, wherein the computer readable instructions, when executed by the processor, further cause the processor to perform operations comprising:

applying, at the virtual transmitter module, a fast Fourier transform algorithm to each received signal waveform to create respective data output;

transmitting the data output to an orthogonal frequency-division multiplexing demodulator to generate respective virtual transmitted data stream;

transmitting each virtual transmitted data stream to an orthogonal frequency-division multiplexing modulator to generate respective modulated data stream;

applying an inverse fast Fourier transform algorithm to each modulated data stream to generate the respective virtual transmitted signal waveform;

storing the virtual transmitted signal waveform at the memory;

retrieving, at a time shift determiner associated with the receiver, the transmitted signal waveform;

comparing, at the time shift determiner, the virtual transmitted signal waveforms to the received signal waveform;

determining, at the time shift determiner, a time shift required to align the virtual transmitted signal waveform to the received signal waveform.

20. The computer readable medium of claim 19, wherein the computer readable instructions, when executed by the processor, further cause the processor to perform operation comprising:

outputting the time shift;

determining, at the receiver, the position of the receiver relative to the transmitter based on the time shift;

obtaining, at the receiver, transmitter location data associated with the transmitter; and

determining, at the receiver, the location of the receiver based upon the transmitter location data for the transmitter and the position of the receiver relative to the transmitter.