Projectile impact location determination system and method

• US 6,367,800 B1
• Filed: 06/07/1999
• Issued: 04/09/2002
• Est. Priority Date: 06/07/1999
• Status: Expired due to Fees

• Current Assignee: Air-Monic LLC
• Original Assignee: Air-Monic LLC
• Inventors: Lancette, Robert W., Sheck, Michael D.
• Primary Examiner(s): Chapman, Jeanette
• Assistant Examiner(s): CHAMBERS, MICHAEL S
• Application Number:
  US09/327,061
• Time in Patent Office: 1,037 Days
• Field of Search: 273/371, 273/372, 235/400
• US Class Current: 273/372
• CPC Class Codes: F41J 5/056 Switch actuation by hit-generated mechanical vibration of the target body, e.g. using shock or vibration transducers
• CPC Class Codes: G01S 5/20 Position of source determined by a plurality of spaced direction-finders

Abstract

An impact location determination system (20) includes a damage resistant strike plate (22) having a planar surface (26) adapted to be impacted by a projectile (28). Pressure sensor assemblies (55) are embedded in the strike plate (22) and detect a pressure disturbance event outwardly propagating as a wave (36) from an impact location (34). The wave (36) propagates through the strike plate (22) at a propagation velocity that is slower than the speed of sound for the strike plate (22). A signal processing circuit (32) measures time difference of arrival figures (196 and 198) between pairs of pressure sensors (140 and 142) and determines the impact location (34) in response to the time difference of arrival figures (196 and 198) and the velocity of the wave (36) through the strike plate (22).

Claims

1. A system for determining the precise location of an impact point of a projectile on the surface of a strike plate with the use of a plurality of pressure sensor pairs, an electronic signal processing circuit comprising:

a) said strike plate having predetermined shape and size sufficient to accommodate use as a projectile target;

b) said strike plate having two substantially flat planar surfaces, a front side planar surface and a rear side planar surface, said surfaces being substantially parallel to each other;

c) means to substantially prevent penetration or damage of said front planar surface of said strike plate by said projectile;

d) means to substantially prevent penetration or damage of said front planar surface of said strike plate by said projectile or multitude of subsequent projectiles at the same point of impact on said front planar surface;

e) a pressure sensor providing means of isolating a pressure disturbance event selected from a plurality of pressure disturbance events urged from any direction within said strike plate when said projectile impacts said strike plate, and said pressure disturbance event having a speed other than the speed of sound;

f) a pressure sensor pair comprised of two said pressure sensors having a predetermined distance between said pressure sensors;

g) a plurality of said pressure sensor pairs;

h) a means for mounting in predetermined locations said plurality of said pressure sensor pairs with respect to said rear planar surface;

i) an electronic signal processing circuit in communication with said plurality of pressure sensor pairs thereby providing a means for determining a multiple of time difference of arrivals of said pressure disturbance event among said plurality of pressure sensor pairs;

j) a means of converting said multiple of time difference of arrivals into a calculated impact point, said calculated impact point being located within a predetermined tolerance of said impact point of said projectile on said front planar surface;

k) a means for converting said calculated impact point into an indicium;

whereby said system will locate the precise impact point of said projectile on said strike plate and generate indicium relative to said precise impact point,

whereby one or a plurality of humans can discern the precise location of an impact point of a projectile on the surface of a strike plate,

whereby one or a plurality or humans can discern the precise locations of a plurality of impact points of a plurality of projectiles on the surface of a strike plate even if such impact points overlay.

2. A system as claimed in claim 1 providing a means to receive, calculate, store and communicate data concerning a plurality of impact points from a plurality of projectiles impacting said strike plate in succession thereby providing a means for determining said plurality of impact points.

3. A system for determining said impact location of said projectile comprising:

a) a plate having a planar surface adapted to be impacted by said projectile without penetration or damage to the planar surface;

b) pressure sensors embedded within said plate at predetermined locations and spaced apart from said planar surface for detecting said pressure disturbance event outwardly propagating through said plate from said impact location on said planar surface;

c) a signal processing circuit in electrical communication with said pressure sensors for measuring the time difference of arrivals of said pressure disturbance event between paired ones of said pressure sensors and determining said impact location on said planar surface in response to said time difference of arrivals, wherein first and second ones of said pressure sensors form a first pair of said paired ones of said pressure sensors and third and fourth ones of said pressure sensors form a second pair of said paired ones of said pressure sensors.

4. A system for determining an impact location of a projectile comprising:

a plate having a planar surface adapted to be impacted by said projectile, and said planar surface having a first edge, a second edge intersecting said first edge at a first corner, and a third edge intersecting said second edge at a second corner;

pressure sensors embedded within said plate and spaced apart from said planar surface for detecting a pressure disturbance event outwardly propagating through said plate from said impact location on said planar surface, said pressure sensors including a housing having a cavity formed therein, a pressure sensing element located in said cavity, a damper abutting said pressure sensing element, and a retainer abutting said damper for securing said pressure sensing element and said damper in said cavity; and

a signal processing circuit in electrical communication with said pressure sensors for measuring time difference of arrivals of said pressure disturbance event between paired ones of said pressure sensors and determining said impact location in response to said time difference of arrivals;

wherein

first and second holes extend into said plate proximate said first corner, each of said first and second holes are located a radial distance from an approximate midpoint of said planar surface, and said first and second holes are separated by a first distance, said first distance being less than said radial distance;

first and second ones of said pressure sensors are located in said first and second holes, said first and second pressure sensors forming a first pair of said paired ones of said pressure sensors;

third and fourth holes extend into said plate proximate said second corner, each of said third and fourth holes are located said radial distance from said approximate midpoint, and said third and fourth holes are separated by a second distance, said second distance being less than said radial distance; and

third and fourth ones of said pressure sensors are located in said third and fourth holes, said third and fourth pressure sensors forming a second pair of said paired ones of said pressure sensors.

5. A system as claimed in claim 4 wherein said planar surface of said plate has a fourth edge intersecting said third edge at a third corner and intersecting said first edge at a fourth corner, and said system further comprises:

a fixed base;

a pivot member coupled to said fixed base and having a pivot axis, such that a distance between said pivot axis and said fourth edge is less than a distance between said pivot axis and second edge; and

mounts secured to said pivot member and said plate proximate said fourth edge for allowing rotation of said plate about said pivot axis relative to said fixed base.