Method and device for detecting a fire shot event in a weapon

• US 8,616,882 B2
• Filed: 07/08/2008
• Issued: 12/31/2013
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: Forselius, Mats, Dahlqvist, Stefan, Isaksson, Anders, Emricson, Ingemar, Chedid, Michel
• Primary Examiner(s): Musselman, Timothy A
• Application Number:
  US12/673,597
• Publication Number:
  US 20110252683A1
• Time in Patent Office: 2,002 Days
• Field of Search: 434 11- 27, 42104-105, 42107-108, 42111-147
• US Class Current: 434/19
• CPC Class Codes: F41G 3/2655 in which the light beam is sent from the weapon to the target

Abstract

A method including measuring a physical quantity having a magnitude that changes in time as a result of a fire shot event so as to obtain a measurement signal, and comparing the measurement signal with a predetermined time-domain fingerprint for said quantity, which fingerprint is characteristic of the way the quantity varies in time upon a fire shot event, in order to confirm the occurrence of a fire shot event in case the measurement signal and the fingerprint match.

Claims

1. A method for detecting a fire shot event in a weapon, the method comprising:

measuring with a measuring device a shock or vibration of the weapon whose magnitude changes in time as a result of a fire shot event so as to obtain a measurement signal, and

comparing the measurement signal with a predetermined time-domain fingerprint for said shock or vibration of the weapon, which fingerprint is characteristic of a way said shock or vibration of the weapon varies in time upon a fire shot event, in order to confirm an occurrence of a fire shot event in case said measurement signal and said fingerprint match,

wherein the measurement signal and the predetermined fingerprint signal are represented by vectors, and the comparison is based on a difference between said vectors.

2. The method according to claim 1, further comprising:

generating a laser beam emulating a fire shot from said weapon in case the occurrence of a fire shot event is confirmed.

3. A method for detecting a fire shot event in a weapon, the method comprising:

measuring with a measuring device a shock or vibration of the weapon whose magnitude changes in time as a result of a fire shot event so as to obtain a measurement signal, and

comparing the measurement signal with a predetermined time-domain fingerprint for said shock or vibration of the weapon, which fingerprint is characteristic of a way said shock or vibration of the weapon varies in time upon a fire shot event, in order to confirm an occurrence of a fire shot event in case said measurement signal and said fingerprint match,

wherein comparing the measurement signal with the predetermined fingerprint comprises;

forming an error estimation E as a weighted sum of absolute differences according to E=W^T|U−

s|,

where W is a weight vector, U is a vector representation of the predetermined fingerprint and s is a vector representation of the measurement signal; and

computing E continuously with an online algorithm where the computation is made on a moving window of the same length as the fingerprint vector U in order to confirm the occurrence of a fire shot event in case E drops below a predetermined threshold value T.

4. The method according to claim 3, wherein the predetermined fingerprint vector U is determined as a mean of a plurality of fingerprint measurements according to

5. The method according to claim 3, wherein the weight vector W is approximated as

6. A shot detection device for detecting a fire shot event in a weapon, said shot detection device comprising:

a measuring module configured to measure a shock or vibration of the weapon whose magnitude changes in time as a result of a fire shot event in said weapon,

a comparison module configured to compare the shock or vibration measured by the measuring module to a predetermined time-domain fingerprint for said shock or vibration of the weapon, wherein the fingerprint is characteristic of a way said shock or vibration of the weapon varies in time upon a fire shot event, and arranged to confirm an occurrence of a fire shot event in case said measurement signal and said fingerprint match, and

an identification module configured to identify a type of firearm to which the device is connected, said shot detection device further being arranged to store a plurality of fingerprints associated with different firearm types and to chose a fingerprint based on the type of firearm identified, and to compare the measurement signal to said chosen fingerprint,

wherein said shot detection device is a separate unit which is arranged to be detachably connected to a firearm or is an integral part of a firearm, wherein the firearm can be real or imitation.

7. The shot detection device according to claim 6, further comprising:

a laser generator configured to generate a laser beam emulating a fire shot from said weapon in case said comparison module has confirmed the occurrence of a fire shot event.

8. The shot detection device according to claim 6, further comprising:

a transmitter configured to transmit information relating to the comparison procedure to an information collection device carried by the user of said weapon.

9. A computer program product stored on a non-transitory medium for detecting a fire shot event in a weapon, wherein said computer program, when executed by a processor in a shot detection device comprising a measuring module configured to measure a shock or vibration of the weapon whose magnitude changes in time as a result of a fire shot event in said weapon, a comparison module configured to compare the shock or vibration measured by the measuring module to a predetermined time-domain fingerprint for said shock or vibration of the weapon, wherein the fingerprint is characteristic of a way said shock or vibration of the weapon varies in time upon a fire shot event, and arranged to confirm an occurrence of a fire shot event in case said measurement signal and said fingerprint match, and an identification module configured to identify a type of firearm to which the device is connected, said shot detection device further being arranged to store a plurality of fingerprints associated with different firearm types and to chose a fingerprint based on the type of firearm identified, and to compare the measurement signal to said chosen fingerprint, wherein said shot detection device is a separate unit which is arranged to be detachably connected to a firearm, and wherein the computer program product is arranged to carry out a method comprising measuring a shock or vibration of the weapon whose magnitude changes in time as a result of a fire shot event so as to obtain a measurement signal, and comparing said measurement signal to a predetermined time-domain fingerprint, which fingerprint is characteristic of the way said shock or vibration of the weapon varies in time upon a fire shot event in order to confirm an occurrence of a fire shot event in case said measurement signal and said fingerprint match, and generate an output being indicative of whether said measurement signal and said fingerprint match, wherein the measurement signal and the predetermined fingerprint signal are represented by vectors, and the comparison is based on a difference between said vectors.