Array of UAVS with magnetometers

• US 10,527,746 B2
• Filed: 02/27/2017
• Issued: 01/07/2020
• Est. Priority Date: 05/31/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Hansen, Jay, Stetson, Jr., John B., DiMario, Michael
• Primary Examiner(s): Hawkins, Dominic E
• Application Number:
  US15/443,422
• Publication Number:
  US 20180348393A1
• Time in Patent Office: 1,044 Days
• CPC Class Codes: G01D 5/14 influencing the magnitude of a current or voltage
• CPC Class Codes: G01R 33/00 Arrangements or instruments for measuring magnetic variables
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence
• CPC Class Codes: G01R 33/022 Measuring gradient
• CPC Class Codes: G01R 33/032 using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: G01V 3/16 specially adapted for use from aircraft G01V3/165 - G01V3/175 take precedence

Abstract

A system includes a plurality of magnetometers that are each configured to generate a vector measurement of a magnetic field. The system also includes a central processing unit that is communicatively coupled to each of the magnetometers. The central processing unit is configured to receive from each of the plurality of magnetometers the respective vector measurement of the magnetic field. The central processing unit is further configured to compare each of the vector measurements to determine differences in the vector measurements and to determine, based on the differences in the vector measurements, that a magnetic object is near the plurality of magnetometers.

Claims

1. A system comprising:

a plurality of unmanned aerial systems (UASs);

a plurality of magnetometers each attached to a respective one of the UASs, wherein each of the magnetometers is configured to generate a vector measurement of a magnetic field from the location of the associated UAS while in motion at a particular time; and

a central processing unit in communication with each of the plurality of magnetometers, wherein the central processing unit is configured to;

receive, from each of the plurality of magnetometers, a first set of vector measurements and corresponding locations of such first set of vector measurements, wherein the corresponding locations indicate where a respective magnetometer was located when the respective vector measurement of the first set of vector measurements was taken;

generate a magnetic baseline map using the first set of vector measurements;

receive, from a first magnetometer of the plurality of magnetometers, a first vector measurement and a first corresponding location;

compare the first vector measurement with the magnetic baseline map using the first corresponding location to determine a first difference vector, wherein the magnetometers are sensitive enough to detect relatively small changes in the first vector measurement relative to the first set of vector measurements based upon fluorescence from a magneto-optical defect center material; and

determine that a magnetic object is in an area corresponding to the area of the magnetic baseline map based on the first difference vector.

2. The system of claim 1, wherein the plurality of magnetometers are diamonds nitrogen-vacancy (DNV) sensors.

3. The system of claim 1, wherein the central processing unit is further configured to determine a location of the magnetic object based on the first difference vector.

4. The system of claim 3, wherein to determine the location of the magnetic object, the central processing unit is configured to determine a point on a surface of the earth that is in an orthogonal direction from the first difference vector.

5. The system of claim 1, wherein the central processing unit is further configured to:

receive, from a second magnetometer of the plurality of magnetometers, a second vector measurement and a second corresponding location; and

compare the second vector measurement with the magnetic baseline map using the second corresponding location to determine a second difference vector,

wherein to determine that the magnetic object is in the area corresponding to the area of the magnetic baseline map, the central processing unit is configured to determine a location of the magnetic object based on the first difference vector and the second difference vector.

6. The system of claim 5, wherein the first vector measurement and the second vector measurement were taken simultaneously.

7. The system of claim 1, wherein each of the magnetometers are attached to the respective UAS via an inertial compensation device.

8. The system of claim 1, wherein the central processing unit is further configured to:

cause a UAS corresponding to the first magnetometer to move to a new location;

receive from the first magnetometer a third vector measurement and a third corresponding location, wherein the third corresponding location is the new location of the UAS corresponding to the first magnetometer;

compare the third vector measurement with the magnetic baseline map using the third corresponding location to determine a third difference vector; and

determine a location of the magnetic object based on the first difference vector and the third difference vector.

9. The system of claim 8, wherein the central processing unit is further configured to determine a type of the magnetic object by comparing the first difference vector and the third difference vector to a database of previously-determined magnetic object types.

10. The system of claim 9, wherein the database of previously-determined magnetic object types comprises a magnetic signature for each of the previously-determined magnetic object types.

11. The system of claim 1, wherein the magnetic object does not generate a magnetic field.

12. The system of claim 11, wherein the magnetic object alters a portion of the earth'"'"'s magnetic field, and wherein the first difference vector corresponds to the portion of the earth'"'"'s magnetic field that is altered by the magnetic field.

13. The system of claim 1, wherein the magnetic object generates the magnetic field, and wherein the first difference vector corresponds to the magnetic field.

14. A method comprising:

receiving, from each of a plurality of magnetometers, a first set of vector measurements and corresponding locations, wherein each of the magnetometers is attached to one of a plurality of unmanned aerial systems (UASs), wherein each of the magnetometers is configured to generate a vector measurement of a magnetic field from the location of the associated UAS while in motion at a particular time, and wherein the corresponding locations indicate where a respective magnetometer was when the respective vector measurement of the first set of vector measurements was taken;

generating a magnetic baseline map using the first set of vector measurements;

receiving, from a first magnetometer of the plurality of magnetometers, a first vector measurement and a first corresponding location;

comparing the first vector measurement with the magnetic baseline map using the first corresponding location to determine a first difference vector, wherein the magnetometers are sensitive enough to detect relatively small changes in the first vector measurement relative to the first set of vector measurements based upon fluorescence from a magneto-optical defect center material; and

determining that a magnetic object is in an area corresponding to the area of the magnetic baseline map based on the first difference vector.

15. The method of claim 14, further comprising determining a location of the magnetic object based on the first difference vector.

16. The method of claim 14, further including:

receiving, from a second magnetometer of the plurality of magnetometers, a second vector measurement and a second corresponding location; and

comparing the second vector measurement with the magnetic baseline map using the second corresponding location to determine a second difference vector,

wherein determining that the magnetic object is in the area corresponding to the area of the magnetic baseline map comprises determining a location of the magnetic object based on the first difference vector and the second difference vector.

17. The method of claim 16, wherein the first vector measurement and the second vector measurement were taken simultaneously.

18. The method of claim 14, further comprising:

causing a UAS corresponding to the first magnetometer to move to a new location;

receiving from the first magnetometer a third vector measurement and a third corresponding location, wherein the third corresponding location is the new location of the UAS corresponding to the first magnetometer;

comparing the third vector measurement with the magnetic baseline map using the third corresponding location to determine a third difference vector; and

determining a location of the magnetic object based on the first difference vector and the third difference vector.

19. The method of claim 18, further comprising determining a type of the magnetic object by comparing the first difference vector and the third difference vector to a database of previously-determined magnetic object types.

20. The method of claim 19, wherein the database of previously-determined magnetic object types comprises a magnetic signature for each of the previously-determined magnetic object types.