System and methods for detecting shooter locations from an aircraft

1. An airborne shooter detection system for a helicopter, comprising:

a plurality of sensors spaced apart on the surface of the body, including at least on the bottom and sides of the helicopter, wherein the plurality of sensors are configured for receiving signals indicative of one or more characteristics of a shockwave of a projectile, and the plurality of sensors are distributed from about the nose of the helicopter to about the tail of the body of the helicopter such that for each of a plurality of different helicopter orientations, at least five of the plurality of sensors can receive the shockwave;

a processor in communication with a plurality of sensors configured for unambiguously determining the location of the source of the projectile; and

an output device in communication with the processor for outputting the determined location.

2. The system of claim 1 , wherein the plurality of sensors includes about seven sensors distributed from about the nose of the helicopter to about the tail of the body of the helicopter such that for each of a plurality of different helicopter orientations, the plurality of sensors can receive the shockwave.

3. The system of claim 1 , wherein the plurality of sensors includes from about 15 to about 18 sensors, distributed from about the nose of the helicopter to about the tail of the body of the helicopter such that for each of a plurality of different helicopter orientations, the plurality of sensors can receive the shockwave.

4. The system of claim 1 , wherein at least two sensors of the plurality of sensors are separated by a distance sufficient to unambiguously determine the location of the source of the projectile with a probability of greater than about 0.8.

5. The system of claim 1 , wherein at least two sensors of the plurality of sensors are separated by a distance from about 8 m to about 11 m.

6. The system of claim 5 , wherein at least two sensors of the plurality of sensors are separated by a distance of about 10 m.

7. The system of claim 1 , further comprising an avionics system in communication with the processor.

8. The system of claim 7 , further comprising at least one of a temperature sensor and pressure sensor coupled to the avionics system.

9. The system of claim 8 , wherein the processor is configured to receive data from the at least one temperature sensor and pressure sensor via the avionics system for unambiguously determining the location of the source of the projectile.

10. The system of claim 1 , wherein the processor includes a shooter location application for determining the location of the source of the projectile.

11. The system of claim 1 , wherein the output device includes at least one of a display, heads-up display (HUD), helmet display, intercom, radio and headset.

12. An airborne shooter detection system for a helicopter, comprising:

a plurality of sensors disposed on the body of the helicopter configured for receiving signals indicative of one or more characteristics of a shockwave of a projectile, wherein the plurality of the sensors are distributed substantially from about the nose of the helicopter to about the tail of the helicopter such that for each of a plurality of different helicopter orientations, at least five of the plurality of sensors can receive the shockwave; and

a processor in communication with the sensors configured for determining the location of the source of the projectile.

13. The system of claim 12 , wherein at least two sensors of the plurality of sensors are separated by a distance of at least 8 m.

14. A method for locating a source of a projectile fired at a helicopter, comprising:

receiving, at a plurality of sensors mounted on a helicopter, signals indicative of one or more characteristics of a shockwave of a projectile fired at the helicopter, wherein the plurality of sensors are distributed from about the nose of the helicopter to about the tail of the helicopter such that for each of a plurality of different helicopter orientations, at least five of the plurality of sensors can receive the shockwave;

analyzing the signals to unambiguously determine a location of a source of the projectile; and

outputting the location of the source.

15. The method of claim 14 , wherein analyzing the signals comprises measuring at least an initial portion of the signals.

16. The method of claim 14 , wherein analyzing the signals further comprises determining from the measured initial portion of the signals Time Differences Of Arrival (TDOA), and determining the location of the source based at least part of the determined TDOAs.

17. The method of claim 14 , wherein analyzing the signals comprises determining, from the arrival times of the shockwave at the sensors, at least one of the arrival angle, the radius of curvature and the spatial gradient of the radius of curvature of the shockwave.

18. The method of claim 17 , wherein analyzing the signals comprises determining the spatial gradient of the radius of curvature of the shockwave, and using the determined spatial gradient to unambiguously determine the location of the source of the projectile.

19. The method of claim 14 , further comprising receiving data from an avionics system mounted aboard the helicopter.

20. The method of claim 19 , wherein the data from the avionics system includes at least one of temperature, attitude, altitude and ground speed.