Firing range

Claim 2

Apparatus for determining the location in a predetermined two-dimensional target area adjacent a target member through which the trajectory of a supersonic projectile passes, said projectile originating from a firing point and directed toward said target member, the apparatus comprising: at least four transducers, means for positioning said at least four transducers in a generally horizontal elongate array adjacent a lower edge of the predetermined target area, said transducers positioned spaced apart one from the other at respective predetermined locations, each said transducer comprising means for providing an output signal in response to an airborne shock wave generated by the supersonic projectile, individual threshold circuit means coupled to each transducer and responsive to said output signal for providing a digital signal when said output signal exceeds a predetermined threshold, the digital signal having a leading edge representing a time at which said airborne shock wave generated by the supersonic projectile impinges on the transducer, and digital processing means, provided with data representing the respective predetermined locations at which the transducers are positioned, and operative for (1) determining time differences between the leading edge of the digital signal associated with one of said transducers relative to the leading edge of the digital signal associated with each of the remainder of the transducers, (2) calculating, from said determined time differences and from the data representing the respective predetermined transducer locations, the location in said predetermined target area through which said trajectory passes, and (3) providing an indication of said calculated location.

Claim 3

An apparatus according to claim 1, wherein said means for providing a digital signal comprises means for receiving and initially amplifying said transducer output signal, and a threshold comparator responsive to the amplified transducer output signal for providing a digital signal only when said amplified signal has an amplitude greater than a predetermined minimum value.

Claim 4

An apparatus according to claim 2, wherein said threshold comparator includes adjustable means for setting said predetermined minimum value.

Claim 5

An apparatus according to claim 1, further comprising: means responsive to said digital signals for generating and temporarily storing information signals representing times at which said digital signals are provided in response to said output signals, and means for subsequently transferring said information signals to said digital processing means.

Claim 6

An apparatus according to claim 4, wherein: said information signal generating and storing means comprises a source of clock signals representing respective instants of time, a latch associated with each transducer and operatively connected for storing an information signal comprising a clock signal from said source representing a time at which a digital signal is provided in response to a transducer output signal, and means for providing a signal identifying each said latch; and said transferring means comprises a buffer, a control device for authorizing transfer of said information signal from each latch to said buffer along with a corresponding identifying signal, and means for transferring signals from said buffer to said digital processing means.

Claim 7

An apparatus according to claim 1, wherein said positioning means positions said transducers at points in a three-dimensional array such that the transducers do not lie in a common plane.

Claim 8

An apparatus according to claim 1, wherein said transducers are positioned by said positioning means in a horizontal linear array adjacent said lower edge of the predetermined target area.

Claim 9

An apparatus according to claim 1, wherein said transducers are positioned by said positioning means between said firing point and said target member.

Claim 10

An apparatus according to claim 1, wherein said transducers are positioned by said positioning means such that said shock wave impinges directly on the transducers.

Claim 11

An apparatus according to claim 1, further comprising means located between said target member and said transducers for shielding said transducer from acoustic waves generated by impact of said projectile on said target member.

Claim 12

An apparatus according to claim 1, further comprising a fifth transducer positioned adjacent said lower edge of the target area and spaced from said at least four transducers, wherein said at least four transducers and said fifth transducer are positioned at respective predetermined locations defining two vertically spaced-apart rows, transducers of one said row being staggered relative to transducers of the other said row such that no transducer lies directly above another transducer.

Claim 13

An apparatus according to claim 1, further including a visual display device responsive to said digital processing means for providing a visual display of said calculated location.

Claim 14

An apparatus according to claim 1, further comprising: means for generating a display signal representative of said target member, means responsive to said display signal for providing a visual representation of said target member, and means coupled to said display signal generating means, said digital processing means and said visual display means for modifying said display signal such that said visual representation contains a visual indication of said calculated location.

Claim 15

An apparatus according to claim 13, wherein said display signal generating means comprises a television camera, and wherein said display signal is modified by inverting a portion of the display signal.

Claim 16

An apparatus according to claim 14, further comprising means for determining x,y coordinates of the point of the visual image being scanned by the television camera at any instant, and means for comparing said x,y coordinates with x,y coordinates representing said calculated location.

Claim 17

An apparatus according to claim 1, further comprising means responsive to said digital processing means for producing a permanent record of said calculated location.

Claim 18

An apparatus according to claim 1, wherein each said transducer comprises a disc-shaped element of a piezoelectric material having a diameter of approximately 5 mm or less, whereby the output signal of the transducer has an optimally fast response time and optimally large amplitude in response to an airborne shock wave.

Claim 19

An apparatus according to claim 17, wherein each said transducer is mounted such that a flat face of each said disc-shaped member is generally vertical, whereby a shock wave generated by the supersonic projectile will impinge tangentially on a circumferential edge of the disc-shaped member, each point on said circumferential edge being substantially equidistant from a central point of the disc-shaped member such that the output signal of the transducer is substantially independent of the direction of arrival of a shock wave at said circumferential edge.

Claim 20

An apparatus according to claim 59, wherein each said transducer comprises a piezoelectric element and a solid member of rigid material for transmitting said airborne shock wave to said piezoelectric element, said member of rigid material having a base in firm contact with said piezoelectric element and having a convex surface exposed to said shock wave, said exposed convex surface being shaped such that every point thereon is substantially at an equal radial distance from a central point on a surface of said piezoelectric element, whereby the rise time and polarity of said output signal is substantially independent of the direction of arrival of a shock wave at said exposed convex surface.

Claim 21

An apparatus according to claim 1, wherein said target member is positioned in said predetermined target area.

Claim 22

An apparatus according to claim 1, further comprising means for moving said target member from a concealed position to a visible position and vice-versa.

Claim 23

An apparatus according to claim 1, further comprising a trolley upon which said transducers and said target member are mounted, said trolley being movable along a predetermined track to permit the position of said target member to be adjusted.

Claim 24

Apparatus for determining the location in a predetermined two-dimensional target area adjacent a target member through which the trajectory of a supersonic projectile passes, said projectile originating from a firing point and directed toward said target member, the apparatus comprising: at least three transducers, means for positioning said at least three transducers in a generally horizontal elongate array adjacent a lower edge of the predetermined target area, said transducers positioned spaced apart one from the other at respective predetermined locations, each said transducer comprising means for providing an output signal in response to an airborne shock wave generated by the supersonic projectile, individual threshold circuit means coupled to each transducer and responsive to said output signal for providing a digital signal when said output signal exceeds a predetermined threshold, the digital signal having a leading edge representing a time at which said airborne shock wave generated by the supersonic projectile impinges on the transducer; and digital processing means, provided with data representing the respective predetermined locations at which the transducers are positioned and with data representing the velocity of the supersonic projectile and the speed of sound propagation in air, and operative for (1) determining time differences between the leading edge of the digital signal associated with one of said transducers relative to the leading edge of the digital signal associated with each of the remainder of the transducers, (2) calculating, from said data representing the respective predetermined transducer locations, said data representing the velocity of the supersonic projectile and the speed of sound propagation in air, and said determined time differences, the location in said predetermined target area through which said trajectory passes, and (3) providing an indication of said calculated location.

Claim 25

Apparatus for determining the location in a predetermined two-dimensional target area adjacent a target member through which the trajectory of a supersonic projectile passes, said projectile originating from a firing point and directed toward said target member, the apparatus comprising: at least three transducers, means for positioning said at least three transducers in a generally horizontal elongate array adjacent a lower edge of the predetermined target area, said transducers positioned spaced apart one from the other at respective predetermined locations, each said transducer comprising means for providing an output signal in response to an airborne shock wave generated by the supersonic projectile, individual threshold circuit means coupled to each transducer and responsive to said output signal for providing a digital signal when said output signal exceeds a predetermined threshold, the digital signal having a leading edge representing a time at which said airborne shock wave generated by the supersonic projectile impinges on the transducer; and digital processing means, provided with data representing the respective predetermined locations at which the transducers are positioned and with data representing the velocity of the supersonic projectile and the speed of sound propagation in air, and operative for (1) determining time differences between the leading edge of the digital signal associated with one of said transducers relative to the leading edge of the digital signal associated with each of the remainder of the transducers, (2) calculating, from said data representing the respective predetermined transducer locations, said data representing the velocity of the supersonic projectile and the speed of sound propagation in air, and said determined time differences, the location in said predetermined target area through which said trajectory passes, and (3) providing an indication of said calculated location.

Claim 26

An apparatus according to claim 23, wherein said means for providing a digital signal comprises means for receiving and initially amplifying said transducer output signal, and a threshold comparator responsive to the amplified transducer output signal for providing a digital signal only when said amplified signal has an amplitude greater than a predetermined minimum value.

Claim 27

An apparatus according to claim 24, wherein said threshold comparator includes adjustable means for setting said predetermined minimum value.

Claim 28

An apparatus according to claim 23, further comprising: means responsive to said digital signals for generating and temporarily storing information signals representing times at which said digital signals are provided in response to said output signals, and means for subsequently transferring said information signals to said digital processing means.

Claim 29

An apparatus according to claim 26, wherein: said information signal generating and storing means comprises a source of clock signals representing respective instants of time, a latch associated with each transducer and operatively connected for storing an information signal comprising a clock signal from said source representing a time at which a digital signal is provided in response to a transducer output signal, and means for providing a signal identifying each said latch; and said transferring means comprises a buffer, a control device for authorizing transfer of said information signal from each latch to said buffer along with a corresponding identifying signal, and means for transferring signals from said buffer to said digital processing means.

Claim 30

An apparatus according to claim 23, wherein said positioning means positions said transducers at points in a three-dimensional array such that the transducers do not lie in a common plane.

Claim 31

An apparatus according to claim 23, wherein said transducers are positioned by said positioning means in a horizontal linear array adjacent said lower edge of the predetermined target area.

Claim 32

An apparatus according to claim 23, wherein said transducers are positioned by said positioning means between said firing point and said target member.

Claim 33

An apparatus according to claim 23, wherein said transducers are positioned by said positioning means such that said shock wave impinges directly on the transducers.

Claim 34

An apparatus according to claim 23, further comprising means located between said target member and said transducers for shielding said transducer from acoustic waves generated by impact of said projectile on said target member.

Claim 35

An apparatus according to claim 23, further including a visual display device responsive to said digital processing means for providing a visual display of said calculated location.

Claim 36

An apparatus according to claim 23, further comprising: means for generating a display signal representative of said target member, means responsive to said display signal for providing a visual representation of said target member, and means coupled to said display signal generating means, said digital processing means and said visual display means for modifying said display signal such that said visual representation contains a visual indication of said calculated location.

Claim 37

An apparatus according to claim 34, wherein said display signal generating means comprises a television camera, and wherein said display signal is modified by inverting a portion of the display signal.

Claim 38

An apparatus according to claim 35, further comprising means for determining x,y coordinates of the point of the visual image being scanned by the television camera at any instant, and means for comparing said x,y coordinates with x,y coordinates representing said calculated location.

Claim 39

An apparatus according to claim 23, further comprising means responsive to said digital processing means for producing a permanent record of said calculated location.

Claim 40

An apparatus according to claim 23, wherein each said transducer comprises a disc-shaped element of a piezoelectric material having a diameter of approximately 5 mm or less, whereby the output signal of the transducer has an optimally fast response time and optimally large amplitude in response to an airborne shock wave.

Claim 41

An apparatus according to claim 38, wherein each said transducer is mounted such that a flat face of each said disc-shaped member is generally vertical, whereby a shock wave generated by the supersonic projectile will impinge tangentially on a circumferential edge of the disc-shaped member, each point on said circumferential edge being substantially equidistant from a central point of the disc-shaped member such that the output signal of the transducer is substantially independent of the direction of arrival of the shock wave at said circumferential edge.

Claim 42

An apparatus according to claim 23, wherein each said transducer comprises a piezoelectric element and a solid member of rigid material for transmitting said airborne shock wave to said piezoelectric element, said member of rigid material having a base in firm contact with said piezoelectric element and having a convex surface exposed to said shock wave, said exposed convex surface being shaped such that every point thereon is substantially at an equal radial distance from a central point on a surface of said piezoelectric element, whereby the rise time and polarity of said output signal is substantially independent of the direction of arrival of a shock wave at said exposed convex surface.

Claim 43

An apparatus according to claim 23, wherein said target member is positioned in said predetermined target area.

Claim 44

An apparatus according to claim 23, further comprising means for moving said target member from a concealed position to a visible position and vice-versa.

Claim 45

An apparatus according to claim 23, further comprising a trolley upon which said transducers and said target member are mounted, said trolley being movable along a predetermined track to permit the position of said target member to be adjusted.

Claim 46

Apparatus for determining the location in a predetermined two-dimensional target area adjacent a target member through which the trajectory of a supersonic projectile passes, said projectile originating from a firing point and directed toward said target member, the apparatus comprising: at least five transducers, means for positioning said at least five transducers in a generally horizontal elongate array adjacent a lower edge of the predetermined target area, said transducers positioned spaced apart one from the other at respective predetermined locations, each said transducer comprising means for providing an output signal in response to an airborne shock wave generated by the supersonic projectile, individual threshold circuit means coupled to each transducer and responsive to said output signal for providing a digital signal when said output signal exceeds a predetermined threshold, the digital signal having a leading edge representing a time at which said airborne shock wave generated by the supersonic projectile impinges on the transducer, and digital processing means, provided with data representing the respective predetermined locations at which the transducers are positioned, and operative for (1) determining time differences between the leading edge of the digital signal associated with one of said transducers relative to the leading edge of the digital signal associated with each of the remainder of the transducers, (2) comparing the determined time differences with one another and selecting a number of said time differences which will produce at least three independent equations from which the location in said predetermined target area through which said trajectory passes may be calculated, (3) calculating, from said selected three time differences and from the data representing the respective predetermined transducer locations, the location in said predetermined target area through which said trajectory passes, and (4) providing an indication of said calculated location.

Claim 47

Apparatus for determining the location in a predetermined two-dimensional target area adjacent a target member through which the trajectory of a supersonic projectile passes, said projectile originating from a firing point and directed toward said target member, the apparatus comprising: at least five transducers, means for positioning said at least five transducers in a generally horizontal elongate array adjacent a lower edge of the predetermined target area, said transducers positioned spaced apart one from the other at respective predetermined locations, each said transducer comprising means for providing an output signal in response to an airborne shock wave generated by the supersonic projectile, individual threshold circuit means coupled to each transducer and responsive to said output signal for providing a digital signal when said output signal exceeds a predetermined threshold, the digital signal having a leading edge representing a time at which said airborne shock wave generated by the supersonic projectile impinges on the transducer, and digital processing means, provided with data representing the respective predetermined locations at which the transducers are positioned, and operative for (1) determining time differences between the leading edge of the digital signal associated with one of said transducers relative to the leading edge of the digital signal associated with each of the remainder of the transducers, (2) comparing the determined time differences with one another and selecting a number of said time differences which will produce at least three independent equations from which the location in said predetermined target area through which said trajectory passes may be calculated, (3) calculating, from said selected three time differences and from the data representing the respective predetermined transducer locations, the location in said predetermined target area through which said trajectory passes, and (4) providing an indication of said calculated location.

Claim 48

An apparatus according to claim 44, wherein said means for providing a digital signal comprises means for receiving and initially amplifying said transducer output signal, and a threshold comparator responsive to the amplified transducer output signal for providing a digital signal only when said amplified signal has an amplitude greater than a predetermined minimum value.

Claim 49

An apparatus according to claim 45, wherein each said threshold comparator includes adjustable means for setting said predetermined minimum value.

Claim 50

An apparatus according to claim 44, further comprising: means responsive to said digital signals for generating and temporarily storing information signals representing times at which said digital signals are provided in response to said output signals, and means for subsequently transferring said information signals to said digital processing means.

Claim 51

An apparatus according to claim 47, wherein: said information signal generating and storing means comprises a source of clock signals representing respective instants of time, a latch associated with each transducer and operatively connected for storing an information signal comprising a clock signal from said source representing a time at which a digital signal is provided in response to a transducer output signal, and means for providing a signal identifying each said latch; and said transferring means comprises a buffer, a control device for authorizing transfer of said information signal from each latch to said buffer along with a corresponding identifying signal, and means for transferring signals from said buffer to said digital processing means.

Claim 52

An apparatus according to claim 44, wherein said positioning means positions said transducers at points in a three-dimensional array such that the transducers do not lie in a common plane.

Claim 53

An apparatus according to claim 44, wherein said transducers are positioned by said positioning means in a horizontal linear array adjacent said lower edge of the predetermined target area.

Claim 54

An apparatus according to claim 44, wherein said transducers are positioned by said positioning means between said firing point and said target member.

Claim 55

An apparatus according to claim 44, wherein said transducers are positioned by said positioning means such that shock wave impinges directly on the transducers.

Claim 56

An apparatus according to claim 44, further comprising means located between said target member and said transducers for shielding said transducer from acoustic waves generated by impact of said projectile on said target member.

Claim 57

An apparatus according to claim 44, further including a visual display device responsive to said digital processing means for providing a visual display of said calculated location.

Claim 58

An apparatus according to claim 44, further comprising: means for generating a display signal representative of said target member, means responsive to said display signal for providing a visual representation of said target member, and means coupled to said display signal generating means, said digital processing means and said visual display means for modifying said display signal such that said visual representation contains a visual indication of said calculated location.

Claim 59

An apparatus according to claim 55, wherein said display signal generating means comprises a television camera, and wherein said display signal is modified by inverting a portion of the display signal.

Claim 60

An apparatus according to claim 56, further comprising means for determining x,y coordinates of the point of the visual image being scanned by the television camera at any instant, and means for comparing said x,y coordinates with x,y coordinates representing said calculated location.

Claim 61

An apparatus according to claim 44, further comprising means responsive to said digital processing means for producing a permanent record of said calculated location.

Claim 62

An apparatus according to claim 44, wherein each said transducer comprises a disc-shaped element of a piezoelectric material having a diameter of approximately 5 mm or less, whereby the output signal of the transducer has an optimally fast response time and optimally large amplitude in response to an airborne shock wave.

Claim 63

An apparatus according to claim 59, wherein each said transducer is mounted such that a flat face of each said disc-shaped member is generally vertical, whereby a shock wave generated by the supersonic projectile will impinge tangentially on a circumferential edge of the disc-shaped member, each point on said circumferential ege being substantially equidistant from a central point of the disc-shaped member such that the output signal of the transducer is substantially independent of the direction of arrival of a shock wave at said circumferential edge.

Claim 64

An apparatus according to claim 44, wherein each said transducer comprises a piezoelectric element and a solid member of rigid material for transmitting said airborne shock wave to said piezoelectric element, said member of rigid material having a base in firm contact with said piezoelectric element and having a convex surface exposed to said shock wave, said exposed convex surface being shaped such that every point thereon is substantially at an equal radial distance from a central point on a surface of said piezoelectric element, whereby the rise time and polarity of said output signal is substantially independent of the direction of arrival of a shock wave at said exposed convex surface.

Claim 65

An apparatus according to claim 44, wherein said target member is positioned in said predetermined target area.

Claim 66

An apparatus according to claim 44, further comprising means for moving said target member from a concealed position to a visible position and vice-versa.

Claim 67

An apparatus according to claim 44, further comprising a trolley upon which said transducers and said target member are mounted, said trolley being movable along a predetermined track to permit the position of said target member to be adjusted.