Self calibrating shooter estimation

• US 8,149,649 B1
• Filed: 09/27/2007
• Issued: 04/03/2012
• Est. Priority Date: 08/24/2004
• Status: Expired due to Fees

• Current Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Original Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Inventors: Brinn, Marshall Seth, Barger, James E., Milligan, Stephen D.
• Primary Examiner(s): LOBO, IAN J
• Application Number:
  US11/904,452
• Publication Number:
  US 20120082006A1
• Time in Patent Office: 1,650 Days
• Field of Search: 367/127, 367/129, 367/906
• US Class Current: 367/127
• CPC Class Codes: F41J 5/06 Acoustic hit-indicating systems, i.e. detecting of shock waves F41J5/056 takes precedence
• CPC Class Codes: G01S 3/808 using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• 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

Disclosed are systems and methods that can be used to detect shooters. The systems and methods described herein use arrival times of a shockwave, produced by a shot, at a plurality of sensors to assign weights to each of the plurality of sensors, and determine a shot trajectory based on the assigned weights.

Claims

1. A method for operating a multi-sensor shooter detection system, comprising

providing a plurality of sensors,

determining arrival times of a shockwave produced by a shot at each of the plurality of sensors,

determining a time residual based at least in part on the arrival times,

determining a contribution of each the arrival times to the time residual,

assigning a weight to each of the plurality of sensors based on the contribution, and

determining a shot trajectory based on the weight.

2. The method of claim 1, wherein assigning a weight includes assigning a weight to each of the plurality of sensors that is inversely proportional to the contribution of the arrival times of the corresponding ones of the plurality of sensors to the time residual.

3. The method of claim 1, further comprising the step of normalizing the contribution to an observed maximum arrival time difference.

4. The method of claim 1, further comprising the step of computing a weighted shockwave arrival time that enhances a contribution from sensors that have a greater reliability.

5. The method of claim 4, further comprising determining a shooter position from a time residual computed with said weighted shockwave arrival time.

6. The method of claim 1, further comprising adjusting the weight of a sensor when the sensor has been repaired.

7. The method of claim 1, wherein the sensor is an acoustic sensor.

8. The method of claim 7, wherein the acoustic sensor is a microphone.

9. The method of claim 1, wherein determining the time residual includes performing least-squares regression for the arrival times.

10. The method of claim 1, wherein the trajectory comprises a trajectory of one of the shot and a subsequent shot.