Acoustic hostile fire indicator

Patent metadata

Field	Value
Publication number	US-9696405-B1
Application number	US-201314012495-A
Country	US
Kind code	B1
Filing date	Aug 28, 2013
Priority date	Dec 5, 2008
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

A system and method for detecting the trajectory of a projectile is presented. One system includes a flash detection sensor, an acoustic sensor, an optical sensor and a processor logic mounted on a vehicle. The flash detection sensor detects a flash of a projectile being launched. The acoustic sensor detects when a blast wave associated with the firing of the projectile reaches the vehicle. The optical sensor takes two or more images of the same projectile. The images are typically not in the visible light spectrum. The processor logic calculates a trajectory of the projectile based on the images and data collected by the acoustic sensor associated with the blast wave. The processor logic may generate a warning signal to warn an operator of the vehicle about the projectile.

First claim

What is claimed is:

1. A system configured for mounting on an aerial vehicle for detecting an airborne projectile launched toward the vehicle; the system comprising:
an annular housing including an annular central wall, a flat annular front surface and a flat annular back surface connected to the central wall, and a curved sidewall extending from an outer perimeter of the back surface, wherein the flat annular front surface defines an array of holes and the flat annular back surface is flush-mounted to the vehicle;
an optical sensor housing including a cylindrical sidewall, a back wall, a flat side surface which angles forwardly and laterally from the back wall, wherein the optical sensor housing is attached to the annular housing;
an acoustic sensor having an array of microphones disposed in the array of holes formed in the flat annular front surface of the annular housing such that the microphones of the array of microphones are recessed from the flat annular front surface and configured to sense when a shock wave associated with the firing of the projectile reaches the vehicle;
an optical sensor mounted in the optical sensor housing configured to take images of the projectile in an ultraviolet light spectrum; and
processor logic configured to calculate a trajectory of the projectile based on the images and data collected by the acoustic sensor associated with the shock wave, wherein the processor logic is configured to generate at least one warning signal to warn an operator of the vehicle about the projectile.

2. The system of claim 1 wherein the processor logic is configured to (a) extract an azimuth and an elevation of the projectile from each image of the projectile taken by the optical sensor; and (b) calculate a trajectory of the projectile based on the azimuth and an elevation of each image.

3. The system of claim 1 wherein the array of microphones are individual microphones equally spaced apart.

4. The system of claim 3 wherein the microphones are arranged in a circle.

5. The system of claim 4 wherein the optical sensor is in a center of the circle.

6. The system of claim 1 further comprising a flash detection sensor, wherein the flash detection sensor and the optical sensor are the same sensor.

7. The system of claim 1 wherein the annular housing further comprises:
an annular flange extending outwardly from the flat annular back surface,
wherein the optical sensor housing is mounted on the annular flange.

8. The system of claim 1 wherein the projectile is a bullet fired from a gun.

9. The system of claim 1 further comprising:
a visual indicator configured to display at least what quadrant the projectile is in responsive to the trajectory of the projectile.

10. The system of claim 1 wherein the vehicle is an aircraft.

11. A method comprising:
at an aerial vehicle, detecting a launch of an airborne projectile launched towards the vehicle using a system including an annular housing, the annular housing including an annular central wall, a flat annular front surface and a flat annular back surface connected to the central wall, and a curved sidewall extending from the back surface, wherein the flat annular front surface defines an array of holes and the flat annular back surface is flush-mounted to the vehicle;
at the vehicle, capturing at different times a plurality of different images of the moving projectile in an ultraviolet light spectrum using the system including an optical sensor mounted in an optical sensor housing including a cylindrical sidewall, a back wall, a flat side surface which angles forwardly and laterally from the back wall, wherein the optical sensor housing is attached to the annular housing;
at the vehicle, determining a time that a shock wave caused by the launch reaches the vehicle using the system including an acoustic sensor having an array of microphones disposed in the array of holes formed in the flat annular front surface of the annular housing such that the microphones of the array of microphones are recessed form the flat annular front surface;
at the vehicle, determining a trajectory of the projectile based on the plurality of images and the time that the shock wave reaches the vehicle using the system including processor logic configured to calculate the trajectory; and
at the vehicle, determining whether to generate an alarm based on the trajectory using the system including processor logic configured to determine whether to generate the alarm based on the trajectory.

12. The method of claim 11 further comprising:
extracting an azimuth and an elevation pair of data of the projectile from each of the images; and wherein the trajectory is determined based on the azimuth and elevation pairs of data.

13. The method of claim 11 wherein at least one of the plurality of images of the projectile is captured before the determining a time that a shock wave reaches the vehicle.

14. The method of claim 11 wherein determining a time that a shock wave reaches the vehicle further comprises:
receiving acoustic data at the array of microphones.

15. The method of claim 11 further comprising:
filtering the acoustic data to remove at least background noise to produce filtered acoustic data.

16. The method of claim 15 further comprising:
convoluting the filtered acoustic data with one or more known acoustic data profiles to produce convoluted data, and wherein the trajectory is based on the convoluted data.

17. The method of claim 11 wherein the projectile is a bullet and the vehicle is an airplane.

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Succi George
• Sutphin Eldon M
• Real Edward C
• Haney Philip J
• Devine William O

Classifications

• H04R1/406

  microphones · CPC title

• H04R2201/401

  2D or 3D arrays of transducers · CPC title

• G01S3/80 Primary

  using ultrasonic, sonic or infrasonic waves · CPC title

• H04R2499/13

  Acoustic transducers and sound field adaptation in vehicles · CPC title

• G01S3/7864

  T.V. type tracking systems · CPC title