Systems and methods of identifying/locating weapon fire using envelope detection

• US 7,710,278 B2
• Filed: 10/30/2007
• Issued: 05/04/2010
• Est. Priority Date: 01/24/2003
• Status: Expired due to Term

• Current Assignee: Shotspotter Incorporated
• Original Assignee: Shotspotter Incorporated
• Inventors: Baxter, Kevin, Fisher, Ken, Holmes, Fred H.
• Primary Examiner(s): Nguyen; Phung
• Application Number:
  US11/981,710
• Publication Number:
  US 20080298176A1
• Time in Patent Office: 917 Days
• Field of Search: 340/573.1, 340/426.19, 340/506, 340/539.13, 340/995.28, 340/521, 340/691.6, 340/825.36, 367/127, 367/129, 367/125
• US Class Current: 340/573.1
• CPC Class Codes: F41H 13/00 Means of attack or defence not otherwise provided for details of radar or sonar systems G01S7/00
• CPC Class Codes: G01S 5/18 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 5/22 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence
• CPC Class Codes: Y10S 367/906 Airborne shock-wave detection

Abstract

Systems and methods are disclosed for processing gunshot information. In one exemplary implementation, there is provided a method for processing gunshot information via identification of characteristics of detected gunfire. Moreover, the method may include detecting a particular gunshot event, deriving envelope information for the particular gunshot event, accessing one or more known envelopes associated with known gunshot events, and associating the particular gunshot event with a known weapon or known weapon types as a function of a comparison of the envelope information of the particular gunshot event with known envelope information associated with one or more known weapons. Other exemplary implementations may include comparing attack, sustain, and delay characteristics of the particular gunshot event with known attack, sustain, and decay characteristics associated with the known weapon.

Claims

1. A method of processing gunshot information via identification of characteristics of detected gunfire, the method comprising:

detecting a particular gunshot event;

deriving an envelope for the particular gunshot event, wherein the envelope includes attack, sustain, and decay characteristics of the particular gunshot event;

accessing known envelope information associated with known gunshot events, wherein the known envelope information includes attack, sustain, and decay information;

associating the particular gunshot event with a known weapon as a function of a comparison of the envelope derived for the particular gunshot event with known envelope data associated with one or more known weapons, wherein the comparison includes comparing one or more attack, sustain, or decay characteristics of the particular gunshot event with known attack, sustain, or decay characteristics associated with the known weapon.

2. The method of claim 1 further comprising:

accessing known spectral information associated with the known gunshot events; and

deriving particular spectral information associated with the particular gunshot event;

wherein the comparison further includes comparing the particular spectral information with the known spectral information.

3. The method of claim 1 wherein gunshot information is measured at a peak of a beginning portion of a received gunshot wave'"'"'s envelope.

4. The method of claim 1 further comprising determining an approximate location of a source of the particular gunshot event.

5. The method of claim 4 wherein the approximate location of the source of the particular gunshot event is determined in connection with a process that includes transmitting arrival time data from a sensor to a host computer.

6. The method of claim 4 wherein determining the location of the source of the particular gunshot event includes performing triangulation of the location as a function of location information of sensors and time of arrival information as to when the acoustic event was detected at the sensors.

7. The method of claim 6 wherein the time of arrival data is communicated over a single channel without latency in connection with synchronizing sensors that detected the particular gunshot event.

8. The method of claim 4 wherein determining the location of the source of the particular gunshot event includes performing triangulation via sensor detection equipment that detects distances to known landmarks.

9. The method of claim 4 wherein determining the location of the source of the particular gunshot event includes solving six equations and six unknown variables.

10. The method of claim 4 wherein determining the location of the source of the particular gunshot event includes processing relative times of arrival of waves from the particular gunshot event at sensors that detected the particular gunshot event.

11. The method of claim 4 wherein determining the location of the source of the acoustic event includes iterative calculations of expanding spheres.

12. The method of claim 4 wherein determining the location of the source of the particular gunshot event includes processing sensor location information from GPS receivers located on sensors that detected the particular gunshot event.

13. The method of claim 1 further comprising accumulating statistical information regarding events from sensors registering the events and scoring the gunshot event as a function of the statistical information.

14. The method of claim 1 further comprising:

processing data including time of arrival information as to when the particular gunshot event was detected at sensors; and

enhancing accuracy of time values beyond accuracy of a clock source via a time mark function associated with a GPS.

15. A computer readable storage medium storing computer readable instructions executable to perform a method of processing gunshot information via identification of characteristics of detected gunfire, the method comprising:

processing a particular gunshot event detected by a sensor;

deriving an envelope for the particular gunshot event, wherein the envelope includes attack, sustain, and decay characteristics of the particular gunshot event;

accessing known envelope data associated with known gunshot events, wherein the known envelope data includes attack, sustain, and decay information;

associating the particular gunshot event with a known weapon as a function of a comparison of the envelope derived for the particular gunshot event with known envelope signature information associated with the known weapon, wherein the comparison includes comparing the attack, sustain, and decay characteristics of the particular gunshot event with known attack, sustain, and decay characteristics associated with the known weapon.

16. The computer readable storage medium of claim 15 wherein the method further comprises:

accessing known spectral information associated with the known gunshot events; and

deriving particular spectral information associated with the particular gunshot event;

wherein the comparison further includes comparing the particular spectral information with the known spectral information.

17. The computer readable storage medium of claim 15 wherein gunshot envelope information is measured at a peak of a beginning portion of a received gunshot wave'"'"'s signal.

18. The computer readable storage medium of claim 15 wherein the method further comprises determining an approximate location of a source of the particular gunshot event.

19. The computer readable storage medium of claim 18 wherein the approximate location of the source of the particular gunshot event is determined in connection with a process that includes transmitting arrival time data from a sensor to a host computer.

20. The computer readable storage medium of claim 15 wherein the method further comprises accumulating statistical information regarding events from sensors registering the events and scoring a gunshot event as a function of the statistical information.