Method, apparatus, and computer program product for processing received signals for locating

• US 9,285,454 B2
• Filed: 03/02/2012
• Issued: 03/15/2016
• Est. Priority Date: 03/04/2011
• Status: Active Grant

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: ZIH Corp. (Zebra Technologies Corporation)
• Inventors: Boyd, Robert W., English, Jerald W., Richardson, Thomas L., Wohl, Michael A.
• Primary Examiner(s): PHAM, TIMOTHY X
• Application Number:
  US13/411,220
• Publication Number:
  US 20120225676A1
• Time in Patent Office: 1,474 Days
• Field of Search: 455/456.6
• US Class Current: 1/1
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: G01S 5/0226 Transmitters
• 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: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

Example embodiments are directed to various aspects of processing received signals for determining a location of a source of the signals. An example method may include generating signal timing information, and determining times for a plurality of window periods for the signal of interest based on the signal timing information. The example method may also include retrieving, from a memory device that stores the signal stream, symbols of the signal of interest based on the window periods, and formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest. Additional and alternative methods and apparatuses are also provided.

Claims

1. A system for locating a signal source, the system comprising:

a plurality of receivers including a first receiver; and

a plurality of node devices, wherein the first receiver includes processing circuitry configured to perform operations including;

receiving a plurality of wireless signal streams that originated from at least one of the node devices, wherein each of the wireless signal streams includes a signal of interest and has a respective carrier frequency;

generating signal timing information including one or more pulses corresponding to a correlation with one or more frequencies based on each of the plurality of wireless signal streams, the pulses being time-compressed portions of the signal of interest;

determining times for a plurality of window periods for the signal of interest with respect to the signal timing information for each of the respective carrier frequencies, wherein each window period is associated with a respective pulse of the signal timing information;

applying times and one or more determined gains for the signal of interest to permit estimate of a phase of the received signal for a time-of-arrival determination;

retrieving, from a memory device that stores the wireless signal streams, symbols of the signal of interest based on the window periods;

formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest;

determining time of arrival information based on the formatted symbols; and

providing the time of arrival information to a location processing service, wherein the location processing service is configured to determine the location of the source of the signal of interest based on the time of arrival information.

2. The system of claim 1, wherein the processing circuitry of the first receiver is configured to format the symbols by filtering data within the retrieved symbols to include only portions of the signal of interest that are associated with the window periods.

3. The system of claim 1, wherein the processing circuitry of the first, receiver is further configured to:

estimate the phase of the signal of interest via utilization of quadrature sampled data from the signal of interest; and

reduce interference and noise by processing a portion of the signal of interest that is in-phase with the estimated phase.

4. The system of claim 1, wherein, the processing circuitry of the first receiver is further configured to store the wireless signal streams in the memory device.

5. The system of claim 4, wherein the processing circuitry of the first receiver configured to store the wireless signal streams stream such that the memory device operates as a circular buffer for incoming wireless signals.

6. The system of claim 1, wherein the processing circuitry of the first receiver is configured to generate the signal timing information via at least one matched filter.

7. The system of claim 1, wherein the processing each of the one or more pulses is time-compressed based on a spread ratio.

8. A method comprising:

receiving a plurality of wireless signal streams that originated from at least one node device, wherein each wireless signal stream includes a signal of interest and has a respective carrier frequency;

generating signal timing information including one or more of pulses corresponding to a correlation with one or more frequencies based on each of the plurality of wireless signal streams, the pulses being time-compressed portions of the signal of interest;

determining times for a plurality of window periods for the signal of interest with respect to the signal timing information for each of the respective carrier frequencies, wherein each window period is associated with a respective pulse of the timing information;

applying times and one or more determined gains for the signal of interest to permit estimate of a phase of the received signal for a time-of-arrival determination;

retrieving, from a memory device that stores the wireless signal streams, symbols of the signal of interest based on the window periods;

formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest;

determining time of arrival information based on the formatted symbols; and

providing the time of arrival information to a location processing service to determine the location of the source of the signal based on the time of arrival information.

9. The method of claim 8, wherein formatting the symbols includes filtering data within the retrieved symbols to include only portions of the signal of interest that are associated with the window periods.

10. The method of claim 8 further comprising:

estimating the phase of the signal of interest via, utilization of quadrature sampled data from the signal of interest; and

reducing interference and noise by processing a portion of the signal of interest that is in-phase with the estimated phase.

11. The method of claim 8, further comprising storing the wireless signal streams in the memory device.

12. The method of claim 11, wherein storing the wireless signal streams includes storing the wireless signal streams such that the memory device operates as a circular buffer for incoming wireless signals.

13. The method of claim 8, wherein generating the signal timing information includes generating the signal timing information via at least one matched lifter.

14. The method of claim 8, wherein generating the signal timing information includes generating the one or more pulses where each pulse is time-compressed based on a spread ratio.

15. An apparatus comprising processing circuitry configured to perform operations including:

receiving a plurality of wireless signal streams from at least one node device, wherein each wireless signal stream includes a signal of interest and has a respective carrier frequency;

generating signal timing information including one or more of pulses corresponding to a correlation with one or more frequencies based on each of the plurality of wireless signal streams, the pulses being time-compressed portions of the signal of interest;

determining times for a plurality of window periods for the signal of interest with respect to the signal timing information for each of the respective carrier frequencies, wherein each window period is associated with a respective pulse of the timing information;

applying times and gains for the signal of interest to permit estimate of a phase of the received signal for a time-of-arrival determination;

retrieving, from a memory device that stores the wireless signal streams, symbols of the signal of interest based on the window periods;

formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest;

determining time of arrival information based on the formatted symbols; and

provide the time of arrival information to a location processing service to determine the location of the source of the signal based on the time of arrival information.

16. The apparatus of claim 15, wherein the processing circuitry is configured to format the symbols by filtering data within the retrieved symbols to include only portions of the signal of interest that are associated with the window periods.

17. The apparatus of claim 15, wherein the processing circuitry is further configured to:

estimate the phase of the signal of Interest via utilization of quadrature sampled data from the signal of interest; and

reduce interference and noise by processing a portion of the signal of interest that is in-phase with the estimated phase.

18. The apparatus of claim 15, wherein the processing circuitry is further configured to store the wireless signal streams in the memory device.

19. The apparatus of claim 18, wherein the processing circuitry is configured to store the wireless signal streams such that the memory device operates as a circular buffer for incoming wireless signals.

20. The apparatus of claim 15, wherein the processing circuitry configured to generate the signal timing information via at least one matched filter.

21. The apparatus of claim 15, wherein the processing circuitry is configured to generate the signal timing information where each pulse is time-compressed based on a spread ratio.

22. The apparatus of claim 15, wherein the apparatus comprises a wireless receiver configured to receive the wireless signal streams transmitted by the at least one node device.

23. The apparatus of claim 15, further comprising at least two antennas configured to receive the wireless signal streams.

24. The apparatus of claim 15, wherein the processing circuitry includes a field programmable logic array.

25. A non-transitory computer-readable storage medium having program code stored thereon, the program code being configured to, upon execution, direct an apparatus to perform operations including:

receiving a plurality of wireless signal streams from at least one node device, wherein each wireless signal stream includes a signal of interest and has a respective carrier frequency;

generating signal timing information including one or more of pulses corresponding to a correlation with one or more frequencies based on each of the plurality of wireless signal streams, the pulses being time-compressed portions of the signal of interest;

determining times for a plurality of window periods for the signal of interest with respect to the signal timing information for each of the respective carrier frequencies, wherein each window period is associated with a respective pulse of the timing information;

applying times and one or more determined gains for the signal of interest to permit estimate of the phase of the received signal for a time-of-arrival determination;

retrieving, from a memory device that stores the wireless signal streams, symbols of the signal of interest based on the window periods;

formatting the symbols of the signal of interest in preparation for determining a location of a source of the signal of interest;

determining time of arrival information based on the formatted symbols; and

providing the time of arrival information to a location processing service to determine the location of the source of the signal based on the time of arrival information.

26. The medium of claim 25, wherein the program code is configured to, upon execution, direct the apparatus to format the symbols by filtering data within the retrieved symbols to include only portions of the signal of interest that are associated with the window periods.

27. The medium of claim 25, wherein the program code is further configured to, upon execution, direct the apparatus to:

estimate the phase of the signal of interest via utilization of quadrature sampled data from the signal of interest; and

reduce interference and noise by processing a portion of the signal of interest that is in-phase with the estimated phase.

28. The medium of claim 25, wherein the program code is further configured to upon execution, direct the apparatus to store the wireless signal streams in the memory device.

29. The medium of claim 28, wherein the program code is configured to, upon execution, direct the apparatus to store the wireless signal streams such that the memory device operates as a circular buffer for incoming wireless signals.

30. The medium of claim 25, wherein the program code is configured to upon execution, direct the apparatus to venerate the signal timing information via at least one matched filter.

31. The medium of claim 25, wherein the program code is configured to, upon execution, direct the apparatus to generate the one or more of pulses where each pulse is time-compressed based on a spread ratio.