Continuous aimpoint tracking system

• US 6,997,716 B2
• Filed: 12/07/2004
• Issued: 02/14/2006
• Est. Priority Date: 03/22/2002
• Status: Expired due to Fees

• Current Assignee: United States Secretary of the Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Skala, James A., Jungwirth, Patrick W., Blackwell, Frank J.
• Primary Examiner(s): Cheng, Joe H.
• Application Number:
  US11/007,914
• Publication Number:
  US 20050103924A1
• Time in Patent Office: 434 Days
• Field of Search: 434/11, 434/16, 434/17, 434 19- 23, 434/27, 434/365, 273/348, 463/3, 463/5, 345/156, 345/158, 345/179, 356/121, 356/141.5, 89/410.5, 348/136, 250/206.1, 701/302, 703/7
• US Class Current: 434/21
• CPC Class Codes: F41G 1/35 for illuminating the target , e.g. flash lights
• CPC Class Codes: F41G 3/2633 using a TV type screen, e.g. a CRT, displaying a simulated target

Abstract

The Continuous Aimpoint Tracking System is comprised of a position detection device (PDD) and a laser pointing device (LPD) that projects an infrared crosshair onto the PDD. The PDD is coupled to a computer and comprises a multitude of photodiodes and associated circuits, the photodiodes being evenly spaced and arranged to form a frame that can be mounted on the computer so as to surround the computer video display. When a “shot” is fired from the LPD, the crosshair projection is interrupted briefly. The PDD determines the position of the four crosshair intersections and reports them to the computer which, in response, generates the video signals that form the resolved aimpoint on the screen, matching the LPD aimpoint to the video image. Further, the tracking system determines the rotation of the LPD over a range of at least 10 degrees clockwise or counter-clockwise.

Claims

1. A continuous aimpoint tracking system for continuously tracking the aimpoint and cant of a shooter, said system comprising:

a computer having a video display for displaying on said video display the aimpoint and cant;

a laser pointing device to be manipulated by said shooter, said laser pointing device being adapted for emitting laser aim signals and being positioned relative to said video display so as to allow the shooter to aim laser signals at any pre-selected area of said video display;

a position detection device, said detection device being coupled to said computer and mounted thereon so as to frame said video display, said detection device sensing said laser aim signals being emitted from said pointing device and generating corresponding data packets at a rate of at least 112.5 times per second and sending said data packets to said computer, said computer processing said data packets to produce and display video signals indicative of the exact location of said aim signals on said video display.

2. A continuous aimpoint tracking system for continuously tracking the aimpoint and cant as set forth in claim 1, wherein said position detection device comprises:

a plurality of photodiodes for producing current signals in response to laser signals impinging thereon, said photodiodes being disposed in a first and a second horizontal rows, said horizontal rows being identical in structure and function, and in a first and a second vertical columns, said vertical columns being identical in structure and function, said rows and columns jointly forming a frame suitable for mounting on said video display of said computer so as to surround said video display;

a means for processing said current signals to yield corresponding digital signals; and

a plurality of bus lines coupled between said photodiodes and said processing means to enable sequential scanning of said photodiodes, such that every 8^th photodiode in a pair of one horizontal row and one vertical column is coupled to the same bus line among said plurality of bus lines, said digital signals being subsequently converted into data packets at a rate of at least 112.5 times per second and input to said computer.

3. A continuous aimpoint tracking system for continuously tracking the aimpoint and cant as set forth in claim 2, wherein any adjacent two of said photodiodes in the same horizontal row or vertical column are further disposed to maintain the exactly same pre-selected spacing therebetween, said spacing being equivalent to the width of said laser aim signal.

4. A continuous aimpoint tracking system as set forth in claim 3, wherein said means for sequential scanning comprises:

a pair of mutually coordinating first and second microcontrollers, said first microcontroller being coupled to scan said first row and said first column of said photodiodes while said second microcontroller is coupled to scan said second row and said second column of said photodiodes;

a means for isolating any selected photodiode from other photodiodes on the same bus line so that sequential scanning can be performed by a particular microcontroller among said microcontrollers, said particular microcontroller being coupled to said selected photodiode, said isolating means being coupled between said photodiodes and said particular microcontroller.

5. A continuous aimpoint tracking system as set forth in claim 4, wherein one of said microcontrollers communicates with said computer.

6. A continuous aimpoint tracking system as set forth in claim 5, wherein said laser pointing device for emitting laser aim signals comprises:

a plurality of lasers for emitting infrared beams, said beams exhibiting a Gaussian distribution across the width of said beams;

a means for powering said lasers;

a means for selectively activating said lasers; and

a means positioned to receive said infrared beams from said lasers, shape said beams and subsequently project said beams in the form of a crosshair onto said position detecting device.

7. A continuous aimpoint tracking system as set forth in claim 6, wherein said means for shaping and projecting a crosshair comprises:

a first cylindrical lens and a second cylindrical lens, each of said lenses being positioned to receive said infrared laser beam from said first laser and said second laser, respectively, and optically diffract said radiation into a horizontal line and a vertical line, respectively, each line exhibiting a Gaussian distribution, said horizontal and vertical lines together forming a crosshair.

8. A continuous aimpoint tracking system as set forth in claim 7, wherein the length of said horizontal line spans at least twice the distance between the outer edges of said vertical columns of said photodiodes in said position detection device.

9. A continuous aimpoint tracking system for continuously tracking the aimpoint of a shooter, said system comprising:

a computer having a display screen for displaying on said screen the aimpoint;

a laser pointing device manipulable by said shooter, said laser pointing device being suitable for emitting laser aim signals that exhibit a Gaussian distribution across the width of said signals and being positioned relative to said display screen so as to allow the shooter to aim said laser signals at any pre-selected area of said screen;

a position detection device coupled to said computer, said position detection device having therein a plurality of photodiodes for producing current signals in response to laser signals impinging thereon, said photodiodes being disposed in a first and a second horizontal rows, said horizontal rows being identical in structure and function, and in a first and a second vertical columns, said vertical columns being identical in structure and function, said rows and columns jointly forming a frame suitable for mounting on said screen of said computer so as to surround said screen, said position detection device further having therein a means for scanning said photodiodes in a pre-determined sequence, a microcontroller coupled to scan said photodiodes, a means for processing said current signals to yield corresponding digital signals, a plurality of bus lines coupled between said photodiodes and said processing means such that every 8^th photodiode in a pair of one horizontal row and one vertical column is coupled to the same bus line among said plurality of bus lines; and

a means for isolating any selected photodiode from other photodiodes on the same bus line so that sequential scanning can be performed by said microcontroller, said isolating means being coupled between said photodiodes and said microcontroller, said digital signals being subsequently converted into data packets and input to said computer at a rate of at least 112.5 times per second and said computer processing said data packets to produce and display video signals on said screen, said video signals indicating location of said aim signals with an accuracy of +/−

0.01 inch.

10. A continuous aimpoint tracking system as set forth in claim 9, wherein said means for processing said current signals comprises:

a plurality of identical processing units, each of said units comprising a current amplifier coupled to one of said bus lines, said current amplifier producing corresponding voltage signals in response to said current signals received from said selected photodiode;

a digital potentiometer set at a pre-selected attenuation step;

a fixed attenuator coupled between said current amplifier and said digital potentiometer, said attenuator receiving said voltage signals from said current amplifier and rendering said voltage signals acceptable to said potentiometer;

an analog-to-digital converter coupled to said microcontroller, said converter producing digital output signals in response to voltage input signals and transmitting said digital output signals to said microcontroller;

a voltage amplifier coupled between said digital potentiometer and said analog-to-digital converter, said voltage amplifier receiving signals from said digital potentiometer and producing, in response, low-impedance signals, said voltage amplifier further transmitting said low-impedance signals to said analog-to-digital converter.