Counter target acquisition radar and acoustic adjunct for classification

• US 7,952,513 B2
• Filed: 06/16/2008
• Issued: 05/31/2011
• Est. Priority Date: 06/16/2008
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Au, Melinda M., Pomeroy, Craig A., Lim, Keith M., Tietjen, Byron W.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US12/139,844
• Publication Number:
  US 20090309781A1
• Time in Patent Office: 1,079 Days
• Field of Search: 342/27, 342/28, 342/52, 342/56, 342/118, 342/146, 342/147, 342/154, 342/157, 367118-123, 367/136, 367/138
• US Class Current: 342/52
• CPC Class Codes: F41G 3/147 based on detection of a firing weapon
• CPC Class Codes: G01S 13/862 Combination of radar systems with sonar systems
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G01S 7/539 using analysis of echo signal for target characterisation; Target signature; Target cross-section

Abstract

A system for classifying targets utilizes radar receptions and acoustic signatures of armament projectiles (e.g., bullets from celebratory rifle fire, mortars, cannon fire, artillery shells, or rockets, etc.) to associate ordinances with radar returns to better utilize a radar'"'"'s resources to acquire and track targets of interest. In one embodiment of the invention the system for classifying targets comprises: a radar system for detecting targets based upon radar receptions; an acoustic system for detecting targets based upon acoustic receptions; and a means for classifying the acoustic receptions into target types; a means for computing range, bearing and time of incidence for the radar receptions and the acoustic receptions; a means for associating the radar receptions and the acoustic receptions according to the classification.

Claims

1. A system for classifying targets comprising:

a radar system for detecting targets based upon radar receptions;

an acoustic system for detecting targets based upon acoustic receptions;

a means for classifying the acoustic receptions into target types;

a means for computing range, bearing and time of incidence for the radar receptions and the acoustic receptions; and

a means for associating the radar receptions and the acoustic receptions according to the classification;

a processing means for determining differences between the radar receptions and the acoustic receptions and creating an association matrix based on the differences.

2. The system of claim 1, wherein the acoustic system for detecting targets based upon acoustic receptions includes a database of acoustic signatures.

3. The system of claim 1, wherein the acoustic system has an aperture and associated sensor for directionally receiving sonic waves.

4. The system of claim 3, wherein the sonic waves are converted into electrical signals for matching the signals to acoustic signatures.

5. The system of claim 4, wherein the electrical signals are converted to digital signals.

6. The system of claim 4, wherein the digital signal is processed by an acoustic beamformer.

7. The system of claim 6, wherein the beamformer provides for phase shifts to each element of the acoustic aperture.

8. The system of claim 4, wherein the signal provides data to estimate the bearing from which a sonic wave is received by the acoustic aperture.

9. The system of claim 3, wherein the range of the target emitting a sonic wave is estimated based on the signal intensity at receiver aperture.

10. The system of claim 5, wherein a correlation means performs a correlation on the signal and the stored acoustic signatures to determine the type of incoming target.

11. The system of claim 4, wherein the signal to noise ratio of the received acoustic signal determines a window of time associated with range and bearing calculations.

12. A method for classifying targets comprises the step of associating one or more radar receptions and one or more acoustic receptions according to a classification of the acoustic receptions and the respective range, bearing and time of incidence for the radar receptions and the acoustic receptions;

and creating an association matrix based upon the difference between the acoustic receptions and corresponding radar receptions.

13. The method of claim 12, further including detecting targets based upon radar receptions;

detecting targets based upon acoustic receptions;

classifying the acoustic receptions into target types;

computing range, bearing and time of incidence for the radar receptions and the acoustic reception.

14. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining if the acoustic receptions are from the same type of target.

15. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining if the range of the acoustic receptions are within a window of a corresponding radar receptions.

16. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining if the bearing of the acoustic receptions are within a window of a corresponding radar receptions.

17. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining if the bearing of the acoustic receptions are within a window of a corresponding radar receptions.

18. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining if the time of arrival of the acoustic receptions are within a window of a corresponding radar receptions.

19. The method of claim 12, wherein the step of associating the radar receptions further includes the step of creating an association matrix based upon the difference between the range of the acoustic receptions and corresponding radar receptions.

20. The method of claim 12, wherein the step of associating the radar receptions further includes the step of creating an association matrix based upon the difference between the bearing of the acoustic receptions and corresponding radar receptions.

21. The method of claim 12, wherein the step of associating the radar receptions further includes the step of creating an association matrix based upon the difference between the time of arrival of the acoustic receptions and corresponding radar receptions.

22. The method of claim 12, wherein the step of associating the radar receptions further includes the step of determining from an association matrix if two rows have a minimum in the same column.

23. The method of claim 12, wherein the step of associating targets based upon acoustic receptions includes the step of accessing a database of acoustic signatures of armament projectiles.

24. The method of claim 13, wherein the step of detecting targets based upon acoustic receptions includes directionally receiving sonic waves.

25. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of computing range, bearing and time of incidence for the radar receptions.

26. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of matching the signals to acoustic signatures stored in a database.

27. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of processing by an acoustic beamformer.

28. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of correlating the received signal and the stored acoustic signatures to determine the type of incoming target.

29. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of using the signal to noise ratio of the received acoustic signal to determine a window of time associated with range and bearing calculations.

30. The method of claim 13, wherein the step of classifying the acoustic receptions into target types further includes the step of applying an amplitude taper in accordance with a Taylor function to the beamformer.

31. A system for classifying targets comprising:

a radar system for detecting targets based upon radar receptions;

an acoustic system for detecting targets based upon acoustic receptions;

a processor configured to classify the acoustic receptions into target types;

compute range, bearing and time of incidence for the radar receptions and the acoustic receptions;

associate the radar receptions and the acoustic receptions according to the classification; and

determine differences between the radar receptions and the acoustic receptions and generate an association matrix based on the differences.

32. The system of claim 31, wherein the processor is further configured to associate the radar receptions by generating an association matrix based upon the difference between range of the acoustic receptions, and the corresponding radar receptions.

33. The system of claim 31, wherein the processor is further configured to associate the radar receptions by generating an association matrix based upon the difference between bearing of the acoustic receptions, and the corresponding radar receptions.

34. The system of claim 31, wherein the processor is further configured to associate the radar receptions by generating an association matrix based upon the difference between time of arrival of the acoustic receptions, and the corresponding radar receptions.