Metadata-based emitter localization

• US 10,739,436 B2
• Filed: 06/27/2019
• Issued: 08/11/2020
• Est. Priority Date: 10/20/2017
• Status: Active Grant

• Current Assignee: HawkEye 360, Inc. (Advance Publications Incorporated)
• Original Assignee: HawkEye 360, Inc. (Advance Publications Incorporated)
• Inventors: O'Shea, Timothy James, McCarthy, Nicholas Aaron, Kawamoto, Darek, Kreinar, Edward
• Primary Examiner(s): Gelin, Jean A
• Application Number:
  US16/454,245
• Publication Number:
  US 20190324110A1
• Time in Patent Office: 411 Days
• CPC Class Codes: G01S 1/022 Means for monitoring or calibrating
• CPC Class Codes: G01S 1/04 Details
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0246 involving frequency difference of arrival or Doppler measurements G01S5/02685 takes precedence
• 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

Abstract

A method includes obtaining signal information corresponding to a plurality of radio signals received at two or more sensing devices from a candidate location, determining a plurality of reconstructed signals based on the signal information, determining time-estimates and frequency-estimates based on a correlation between the plurality of radio signals and the plurality of reconstructed signals, determining metadata corresponding to the plurality of radio signals based on the signal information, the time-estimates, or the frequency-estimates, transmitting at least a portion of the metadata to an information combining node, obtaining the portion of the metadata from the information combining node, determining a relationship between the metadata, and determining the candidate location based on the metadata and the relationship between the metadata. Transmission of the plurality of radio signals to the information combining node is restricted based on a bandwidth of the two or more sensing devices or the information combining node.

Claims

1. A method comprising:

obtaining, from a first sensing device, first information corresponding to a first radio signal received at the first sensing device from a candidate location;

determining a first reconstructed signal corresponding to the first radio signal based on the first information;

determining at least one of a first time-estimate or a first frequency-estimate based on a correlation between the first radio signal and the first reconstructed signal;

determining a first bandwidth of the first sensing device;

in response to determining the first bandwidth of the first sensing device, obtaining first metadata corresponding to the first radio signal, wherein the first metadata are determined based on (i) the first bandwidth of the first sensing device, and (ii) at least one of the first information, the first time-estimate, or the first frequency-estimate;

obtaining, from a second sensing device, second information corresponding to a second radio signal received at the second sensing device from the candidate location;

determining a second reconstructed signal corresponding to the second radio signal based on the second information;

determining at least one of a second time-estimate or a second frequency-estimate based on correlation between the second radio signal and the second reconstructed signal;

determining a second bandwidth of the second sensing device;

in response to determining the second bandwidth of the second sensing device, obtaining second metadata corresponding to the second radio signal, wherein the second metadata are determined based on (i) the second bandwidth of the second sensing device and (ii) at least one of the second information, the second time-estimate, or the second frequency-estimate;

determining a relationship between the first metadata and the second metadata; and

determining the candidate location based on the first metadata, the second metadata, and the relationship between the first metadata and the second metadata,

wherein obtaining the first information comprises;

generating a data stream by digitizing the first radio signal, and

obtaining, from the data stream, information derived from the first radio signal, and

wherein obtaining the information derived from the first radio signal comprises obtaining, from the data stream, at least one of a time of arrival of the first radio signal at the first sensing device, a frequency of the first radio signal at the time of arrival, a frequency offset associated with the first radio signal, a signal to noise ratio associated with the first radio signal, information bits included in the data stream corresponding to the first radio signal, or a signal parameter that defines one or more features of the first radio signal.

2. The method of claim 1, wherein determining the first bandwidth comprises determining a bandwidth for transmitting the first metadata from the first sensing device, the first bandwidth being less than a bandwidth for transmitting the first radio signal from the first sensing device, and

wherein determining the second bandwidth comprises a bandwidth for transmitting the second metadata from the second sensing device, the second bandwidth being less than a bandwidth for transmitting the second radio signal from the second sensing device.

3. The method of claim 2, further comprising:

transmitting at least one of the first metadata or the second metadata to an information combining node through a communications bus communicably coupled to the information combining node.

4. The method of claim 3, further comprising:

determining a bandwidth of the communications bus; and

in response to determining the bandwidth of the communications bus, receiving, at the information combining node, at least one of the first metadata or the second metadata through the communications bus based on the first bandwidth of the first sensing device, the second bandwidth of the second sensing device, and the bandwidth of the communications bus.

5. The method of claim 3, wherein the communications bus comprises a band of frequencies that includes at least one of a VHF-band, a UHF-band, an S-band, a Ku-band, a Ka-band, or an X-band that are configured to carry a radio signal.

6. The method of claim 1, further comprising:

determining a first memory space of the first sensing device for storing the first metadata, the first memory space being less than a memory space for storing the first radio signal, wherein obtaining the first metadata corresponding to the first radio signal comprises determining an amount of the first metadata that is less than or equal to the first memory space; and

determining a second memory space of the second sensing device for storing the second metadata, the second memory space being less than a memory space for storing the second radio signal, wherein obtaining the second metadata corresponding to the second radio signal comprises determining an amount of the second metadata that is less than or equal to the second memory space.

7. The method of claim 1, wherein the information bits included in the data stream comprise information representing at least one of an identity of an emitter corresponding to the first radio signal or a location of the emitter corresponding to the first radio signal.

8. The method of claim 7, further comprising:

identifying a candidate emitter corresponding to the first radio signal, wherein identifying the candidate emitter comprises;

determining an identity of the emitter from the information bits;

obtaining a reference signal parameter corresponding to the identity of the emitter;

comparing a signal parameter of the first radio signal to the reference signal parameter; and

based on the comparing, determining whether the identity of the emitter is an expected identity of the emitter corresponding to the first radio signal.

9. The method of claim 1, wherein determining the first reconstructed signal comprises determining the first reconstructed signal based on at least one of the time of arrival of the first radio signal at the first sensing device, the frequency of the first radio signal at the time of arrival, the signal to noise ratio of the first radio signal, the signal parameter that defines the one or more features of the first radio signal, the information bits included in the first radio signal, or the signal parameter that defines the one or more features of the first radio signal.

10. The method of claim 9, wherein obtaining the first metadata corresponding to the first radio signal comprises obtaining descriptive information corresponding to at least one of the time of arrival of the first radio signal at the first sensing device, the frequency of the first radio signal at the time of arrival, the signal to noise ratio of the first radio signal, information bits included in the first radio signal, or the signal parameter that defines the one or more features of the first radio signal.

11. The method of claim 1, wherein obtaining the first metadata corresponding to the first radio signal comprises obtaining descriptive information corresponding to at least one of a first time of arrival at which the first radio signal arrived at the first sensing device, or a first frequency of arrival of the first radio signal received at the first sensing device at the first time of arrival, and

wherein obtaining the second metadata corresponding to the second radio signal comprises obtaining descriptive information corresponding to at least one of a second time of arrival at which the second radio signal arrived at the second sensing device, or a second frequency of arrival of the second radio signal received at the second sensing device at the second time of arrival.

12. The method of claim 11, wherein determining the candidate location comprises:

obtaining information regarding a trajectory of at least one of the first sensing device or the second sensing device; and

identifying a candidate emitter corresponding to the first radio signal and the second radio signal based on at least one of the information regarding the trajectory of at least one of the first sensing device or the second sensing device, the relationship between the first metadata and the second metadata, the first metadata, or the second metadata.

13. The method of claim 12, wherein identifying the candidate emitter comprises:

obtaining information regarding the candidate emitter;

determining whether the first metadata or the second metadata corresponds to the information regarding the candidate emitter; and

identifying the candidate emitter based on a determination that the first metadata or the second metadata corresponds to the information regarding the candidate emitter,

wherein determining the candidate location further comprises determining the candidate location from estimated locations corresponding to the information regarding the candidate emitter, the trajectory of at least one of the first sensing device or the second sensing device, the relationship between the first metadata and the second metadata, the first metadata, and the second metadata.

14. The method of claim 13, wherein the information regarding the candidate emitter includes at least one of a type of the candidate emitter, a history of locations of the candidate emitter, a travel schedule of the candidate emitter, a frequency band of an emission from the candidate emitter, a frequency of the emission, a frequency offset of the emission, a pulse shape of the emission, a modulation parameter of the emission, or an acoustic or voice content included in the emission.

15. The method of claim 13, wherein obtaining the information regarding the candidate emitter comprises obtaining the information regarding the candidate emitter from at least one of the first metadata, the second metadata, the first sensing device, the second sensing device, another sensing device, an information repository, or an internet source that specifies a type of the candidate emitter, a travel schedule of the candidate emitter, or a frequency band of an emission from the candidate emitter.

16. The method of claim 1, wherein the first sensing device and the second sensing device include at least one of a Low Earth Orbit (LEO) satellite, a Medium Earth Orbit (MEO) satellite, a Geosynchronous Orbit (GEO) satellite, a Highly Elliptical Orbit (HEO) satellite, a nano satellite, an unmanned aerial vehicle (UAV), a terrestrial vehicle, a spacecraft, or a mobile platform.

17. The method of claim 1, further comprising one of:

transmitting the first metadata from the first sensing device to the second sensing device;

or

transmitting the second metadata from the second sensing device to the first sensing device.

18. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, are configured to cause the one or more processors to perform operations comprising:

obtaining, from a first sensing device, first information corresponding to a first radio signal received at the first sensing device from a candidate location;

determining a first reconstructed signal corresponding to the first radio signal based on the first information;

determining at least one of a first time-estimate or a first frequency-estimate based on a correlation between the first radio signal and the first reconstructed signal;

determining a first bandwidth of the first sensing device;

in response to determining the first bandwidth of the first sensing device, obtaining first metadata corresponding to the first radio signal, wherein the first metadata are determined based on (i) the first bandwidth of the first sensing device, and (ii) at least one of the first information, the first time-estimate, or the first frequency-estimate;

obtaining, from a second sensing device, second information corresponding to a second radio signal received at the second sensing device from the candidate location;

determining a second reconstructed signal corresponding to the second radio signal based on the second information;

determining at least one of a second time-estimate or a second frequency-estimate based on correlation between the second radio signal and the second reconstructed signal;

determining a second bandwidth of the second sensing device;

in response to determining the second bandwidth of the second sensing device, obtaining second metadata corresponding to the second radio signal, wherein the second metadata are determined based on (i) the second bandwidth of the second sensing device and (ii) at least one of the second information, the second time-estimate, or the second frequency-estimate;

determining a relationship between the first metadata and the second metadata; and

determining the candidate location based on the first metadata, the second metadata, and the relationship between the first metadata and the second metadata,

wherein obtaining the first information comprises;

generating a data stream by digitizing the first radio signal, and

obtaining, from the data stream, information derived from the first radio signal, and

wherein obtaining the information derived from the first radio signal comprises obtaining, from the data stream, at least one of a time of arrival of the first radio signal at the first sensing device, a frequency of the first radio signal at the time of arrival, a frequency offset associated with the first radio signal, a signal to noise ratio associated with the first radio signal, information bits included in the data stream corresponding to the first radio signal, or a signal parameter that defines one or more features of the first radio signal.

19. The non-transitory computer-readable medium of claim 18, wherein determining the first bandwidth comprises determining a bandwidth for transmitting the first metadata from the first sensing device, the first bandwidth being less than a bandwidth for transmitting the first radio signal from the first sensing device, and

wherein determining the second bandwidth comprises a bandwidth for transmitting the second metadata from the second sensing device, the second bandwidth being less than a bandwidth for transmitting the second radio signal from the second sensing device.

20. The non-transitory computer-readable medium of claim 19, wherein the operations further comprise:

transmitting at least one of the first metadata or the second metadata to an information combining node through a communications bus communicably coupled to the information combining node.

21. The non-transitory computer-readable medium of claim 20, wherein the operations further comprise:

determining a bandwidth of the communications bus; and

in response to determining the bandwidth of the communications bus, receiving, at the information combining node, at least one of the first metadata or the second metadata through the communications bus based on the first bandwidth of the first sensing device, the second bandwidth of the second sensing device, and the bandwidth of the communications bus.

22. The non-transitory computer-readable medium of claim 18, wherein the operations further comprise:

determining a first memory space of the first sensing device for storing the first metadata, the first memory space being less than a memory space for storing the first radio signal, wherein obtaining the first metadata corresponding to the first radio signal comprises determining an amount of the first metadata that is less than or equal to the first memory space; and

determining a second memory space of the second sensing device for storing the second metadata, the second memory space being less than a memory space for storing the second radio signal, wherein obtaining the second metadata corresponding to the second radio signal comprises determining an amount of the second metadata that is less than or equal to the second memory space.

23. A system comprising:

a first sensing device and a second sensing device;

one or more processors; and

storage media storing instructions that, when executed by the one or more processors, are configured to cause the one or more processors to perform operations comprising;

obtaining, from a first sensing device, first information corresponding to a first radio signal received at the first sensing device from a candidate location;

determining a first reconstructed signal corresponding to the first radio signal based on the first information;

determining at least one of a first time-estimate or a first frequency-estimate based on a correlation between the first radio signal and the first reconstructed signal;

determining a first bandwidth of the first sensing device;

in response to determining the first bandwidth of the first sensing device, obtaining first metadata corresponding to the first radio signal, wherein the first metadata are determined based on (i) the first bandwidth of the first sensing device, and (ii) at least one of the first information, the first time-estimate, or the first frequency-estimate;

obtaining, from a second sensing device, second information corresponding to a second radio signal received at the second sensing device from the candidate location;

determining a second reconstructed signal corresponding to the second radio signal based on the second information;

determining at least one of a second time-estimate or a second frequency-estimate based on correlation between the second radio signal and the second reconstructed signal;

determining a second bandwidth of the second sensing device;

in response to determining the second bandwidth of the second sensing device, obtaining second metadata corresponding to the second radio signal, wherein the second metadata are determined based on (i) the second bandwidth of the second sensing device and (ii) at least one of the second information, the second time-estimate, or the second frequency-estimate;

determining a relationship between the first metadata and the second metadata; and

determining the candidate location based on the first metadata, the second metadata, and the relationship between the first metadata and the second metadata,

wherein obtaining the first information comprises;

generating a data stream by digitizing the first radio signal, and

obtaining, from the data stream, information derived from the first radio signal, and

wherein obtaining the information derived from the first radio signal comprises obtaining, from the data stream, at least one of a time of arrival of the first radio signal at the first sensing device, a frequency of the first radio signal at the time of arrival, a frequency offset associated with the first radio signal, a signal to noise ratio associated with the first radio signal, information bits included in the data stream corresponding to the first radio signal, or a signal parameter that defines one or more features of the first radio signal.

24. The system of claim 23, wherein the first sensing device and the second sensing device include at least one of a Low Earth Orbit (LEO) satellite, a Medium Earth Orbit (MEO) satellite, a Geosynchronous Orbit (GEO) satellite, a Highly Elliptical Orbit (HEO) satellite, a nano satellite, an unmanned aerial vehicle (UAV), a terrestrial vehicle, a spacecraft, or a mobile platform.

25. The system of claim 23, wherein determining the first bandwidth comprises determining a bandwidth for transmitting the first metadata from the first sensing device, the first bandwidth being less than a bandwidth for transmitting the first radio signal from the first sensing device, and

wherein determining the second bandwidth comprises a bandwidth for transmitting the second metadata from the second sensing device, the second bandwidth being less than a bandwidth for transmitting the second radio signal from the second sensing device.

26. The system of claim 25, wherein the operations further comprises:

transmitting at least one of the first metadata or the second metadata to an information combining node through a communications bus communicably coupled to the information combining node.

27. The system of claim 26, wherein the information combining node comprises at least one of a ground station, a satellite, a data center, a ship control center, or a satellite control center, and

wherein the communications bus comprises a band of frequencies that includes at least one of a VHF-band, a UHF-band, an S-band, a Ku-band, a Ka-band, or an X-band that are configured to carry a radio signal.

28. A method comprising:

obtaining, from a first sensing device, first information corresponding to a first radio signal received at the first sensing device from a candidate location;

determining a first reconstructed signal corresponding to the first radio signal based on the first information;

determining at least one of a first time-estimate or a first frequency-estimate based on a correlation between the first radio signal and the first reconstructed signal;

determining a first bandwidth of the first sensing device;

in response to determining the first bandwidth of the first sensing device, obtaining first metadata corresponding to the first radio signal, wherein the first metadata are determined based on (i) the first bandwidth of the first sensing device, and (ii) at least one of the first information, the first time-estimate, or the first frequency-estimate;

obtaining, from a second sensing device, second information corresponding to a second radio signal received at the second sensing device from the candidate location;

determining a second reconstructed signal corresponding to the second radio signal based on the second information;

determining at least one of a second time-estimate or a second frequency-estimate based on correlation between the second radio signal and the second reconstructed signal;

determining a second bandwidth of the second sensing device;

in response to determining the second bandwidth of the second sensing device, obtaining second metadata corresponding to the second radio signal, wherein the second metadata are determined based on (i) the second bandwidth of the second sensing device and (ii) at least one of the second information, the second time-estimate, or the second frequency-estimate;

determining a relationship between the first metadata and the second metadata; and

determining the candidate location based on the first metadata, the second metadata, and the relationship between the first metadata and the second metadata,

wherein determining the first bandwidth comprises determining a bandwidth for transmitting the first metadata from the first sensing device, the first bandwidth being less than a bandwidth for transmitting the first radio signal from the first sensing device, and

wherein determining the second bandwidth comprises a bandwidth for transmitting the second metadata from the second sensing device, the second bandwidth being less than a bandwidth for transmitting the second radio signal from the second sensing device.

29. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, are configured to cause the one or more processors to perform operations comprising:

obtaining, from a first sensing device, first information corresponding to a first radio signal received at the first sensing device from a candidate location;

determining a first reconstructed signal corresponding to the first radio signal based on the first information;

determining at least one of a first time-estimate or a first frequency-estimate based on a correlation between the first radio signal and the first reconstructed signal;

determining a first bandwidth of the first sensing device;

in response to determining the first bandwidth of the first sensing device, obtaining first metadata corresponding to the first radio signal, wherein the first metadata are determined based on (i) the first bandwidth of the first sensing device, and (ii) at least one of the first information, the first time-estimate, or the first frequency-estimate;

obtaining, from a second sensing device, second information corresponding to a second radio signal received at the second sensing device from the candidate location;

determining a second reconstructed signal corresponding to the second radio signal based on the second information;

determining at least one of a second time-estimate or a second frequency-estimate based on correlation between the second radio signal and the second reconstructed signal;

determining a second bandwidth of the second sensing device;

in response to determining the second bandwidth of the second sensing device, obtaining second metadata corresponding to the second radio signal, wherein the second metadata are determined based on (i) the second bandwidth of the second sensing device and (ii) at least one of the second information, the second time-estimate, or the second frequency-estimate;

determining a relationship between the first metadata and the second metadata; and

determining the candidate location based on the first metadata, the second metadata, and the relationship between the first metadata and the second metadata,

wherein determining the first bandwidth comprises determining a bandwidth for transmitting the first metadata from the first sensing device, the first bandwidth being less than a bandwidth for transmitting the first radio signal from the first sensing device, and

wherein determining the second bandwidth comprises a bandwidth for transmitting the second metadata from the second sensing device, the second bandwidth being less than a bandwidth for transmitting the second radio signal from the second sensing device.