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WO1994025816A1 - Point de detection d'incidence - Google Patents

Point de detection d'incidence Download PDF

Info

Publication number
WO1994025816A1
WO1994025816A1 PCT/GB1994/000899 GB9400899W WO9425816A1 WO 1994025816 A1 WO1994025816 A1 WO 1994025816A1 GB 9400899 W GB9400899 W GB 9400899W WO 9425816 A1 WO9425816 A1 WO 9425816A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
radiation
gun
card
detecting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1994/000899
Other languages
English (en)
Inventor
Lawrence Gerard Marini
Guy St. John Mason
Neil Morris
Mark Peter Emptage
Raymond John Bridgwater
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales Training and Simulation Ltd
Link Miles Ltd
Original Assignee
Thales Training and Simulation Ltd
Link Miles Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thales Training and Simulation Ltd, Link Miles Ltd filed Critical Thales Training and Simulation Ltd
Priority to AU65755/94A priority Critical patent/AU6575594A/en
Publication of WO1994025816A1 publication Critical patent/WO1994025816A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G3/00—Aiming or laying means
    • F41G3/26—Teaching or practice apparatus for gun-aiming or gun-laying
    • F41G3/2616—Teaching or practice apparatus for gun-aiming or gun-laying using a light emitting device
    • F41G3/2622—Teaching or practice apparatus for gun-aiming or gun-laying using a light emitting device for simulating the firing of a gun or the trajectory of a projectile
    • F41G3/2627—Cooperating with a motion picture projector

Definitions

  • This invention relates to point of incidence detection and especially, but not exclusively, to small arms trainers.
  • a small arms trainer is an apparatus for presenting to one or more observers a visual display simulating a real life scene for the purpose of training in the use of small arms. It may provide for both individual marksmanship and section training.
  • the display may be produced by a slide, or a TV or graphics projector illuminating a screen in front of the trainee, or the trainee may directly view a TV or graphics monitor, or a small mechanical display.
  • the displayed scene is much closer to the trainee than in real life. This prevents the trainee from learning the correct eye-focus procedures when using iron sights and may cause focussing problems if optical sights are fitted to his weapon.
  • It is an object of this invention is to provide improved resolution and accuracy in determining the point of aim of simulated weapons.
  • a preferred embodiment of this invention provides significantly improved training in the use of small arms through the use of a display that avoids focus problems, allows easy and rapid movement between firing positions while maintaining correct perspective and offers economy of use through trainees sharing the display, again whilst maintaining correct perspective.
  • a means of determining the point of aim of a weapon is provided. This means may include an infra red beam projector mounted on the weapon and a position sensitive detector viewing the input image surface.
  • Preferred embodiments of the invention provide: a system for determining the point of incidence of a light source on a plane using a combination of coarse and fine detectors; a system for determining the individual points of incidence of multiple light sources on a plane using time-division multiplexed modulation; a system for combining multiple detectors to determine the point of incidence of a light source on a plane to a fine/high resolution; and a system for calibrating a computer generated image, in one coordinate system, with an array of detectors in a separate coordinate system using a combination of IR and visible light blocking filters.
  • a concave mirror is positioned for viewing by one or more trainees, and facing a convex input image surface which may be the face of a TV/graphics monitor or a screen illuminated by an optical projector, the mirror being so located that it redirects light from the input image surface to the trainee's eyes whereby the or each trainee sees in the mirror a distant image of the input image surface.
  • Figure 1 is a schematic plan view of a small arms trainer embodying the invention and having sufficient size and equipment for four marksman who are shown in the prone position.
  • Figure 2 is a schematic plan view of the small arms trainer of Figure 1 showing four marksman with different simulated weapons and appropriate different firing positions.
  • Figure 3A is a schematic side view of the small arms trainer of Figures 1 and 2 showing one marksman in the prone position.
  • Figure 3B is a schematic side view of the small arms trainer of Figures 1 and 2 showing two marksman in respectively the standing and kneeling firing positions.
  • Figure 3C is a schematic side view of the small arms trainer of Figures 1 and 2 showing a single marksman using a simulated weapon requiring a sitting position.
  • Figure 3D is a schematic side view of the small arms trainer of Figures 1 and 2 showing a single marksman using a simulated machine gun.
  • Figure 3E is a schematic side view of the small arms trainer of Figures 1 and 2 showing two marksman respectively in standing and kneeling positions, using simulated anti-tank gun weapons.
  • Figure 4A is a schematic plan view of a mirror, template, and screen arrangement for a small arms trainer embodying the invention and of sufficient size for five marksmen.
  • Figure 4B is a schematic plan view of one lane portion of the template illustrated in Figure 4A, and showing mounting frames for one projector and one camera assembly.
  • Figure 5 is a schematic plan view of a small arms trainer embodying the invention and showing the equipment required for one marksma .
  • Figure 6A is a schematic sectional view of one projector for use in the embodiments of Figures 1 and 2 and 5.
  • Figure 6B is a graphical representation of the portion of the screen of an embodiment of Figures 1 and 2 or 5, the portion being that for a single marksman and indicating the fields of view of five cameras forming the camera assembly for the marksman.
  • Figure 7 is a vertical sectional view through a hand gun modified to serve as a simulated or replica weapon in an embodiment according to Figures 1 and 2 or 5, and showing the beam forming equipment comprising an LED with a telephoto system attached to the barrel of the gun below the sight line.
  • Figure 8 is a schematic representation of a spherical ball lens incorporated in the LED and the lenses of the telephoto system shown in Figure 7.
  • Figure 9 is a vertical sectional view of an LED and telephoto system attachment for a rifle.
  • Figure 10 is a schematic representation of part of a gun of rifle type for use in a small arms trainer according to Figures 1 and 2 or 5 and showing the positions of transducers incorporated in the gun.
  • Figure 11 is a block diagram of electrical and electronic units comprising a small arms trainer according to Figure 5 and showing the relative positions of the units in relation to the screen and mirror of the trainer and indicating paths for electrical signals and paths for optical (infra-red) emissions from the guns.
  • Figure 12 is a block diagram showing cable interconnections between the instructor's operating station (IOS) and the five personal computers (PC1-PC5) of the five firing stations of the trainer of Figure 5.
  • IOS instructor's operating station
  • PC1-PC5 personal computers
  • Figure 13 is a block diagram of the personal computer and other equipment at or connected to one firing station of the trainer of Figure 5.
  • Figure 14 is a block diagram corresponding to the diagram of Figure 13 but showing more detail of interconnections and power supply.
  • Figure 15 is a schematic representation of connector and circuit card slots at the rear of the personal computer of one firing station according to Figure 14.
  • Figure 16 is a schematic representation of a marksman's switch panel at a firing station according to Figure 14.
  • Figure 17 is a schematic block diagram of a communications-circuit card of a firing station personal computer as in Figures 14 and 15.
  • Figures 18A and 18B are schematic block diagrams of circuits included on a weapon aimpoint circuit card for a personal computer according to Figures 14 and 15.
  • FIG 19 is a schematic block diagram of a weapon recoil circuit card connected to the personal computer and the transducers of the associated gun of a firing station according to Figure 14.
  • Figure 20 is a block diagram of the instructor's operating station in the embodiment of Figure 5.
  • Figure 21 is a more detailed block diagram of the instructor's operating station of Figure 20, showing power connections .
  • Figure 22 is a schematic representation of slots for connectors and circuit cards at the rear of a personal computer nc u e n t e nstructor s operat ng stat on o gures an 21.
  • the screen providing the original image eg, the monitor screens, or the diffusing screen
  • the screen may be placed at a position about 60/100 of the radius of the mirror from the centre of curvature of the mirror, then adjusted back and forth relative to the mirror until a satisfactory image is provided at the intended viewing positions. There is a relationship between the degree of collimation obtained and the amount of distortion apparent in the viewed image.
  • the monitor screen will be preferably 25 inches diagonally (63.5 cm) .
  • a 3 metre radius mirror can be used, having a usable area measuring 2.5 metres in height and 1 metre width.
  • Such an arrangement provides at least a 1.5 metre difference vertically between the standing and prone viewing positions.
  • Two such mirrors can be used with the monitor for two marksmen.
  • a field of view for each man of at least 12° vertically by at least 12° horizontally may be provided.
  • An infra-red (IR) light-emitting diode (LED) is mounted with collimating optics on the simulated weapon.
  • the IR LED is one with a "sweet spot", conventionally intended for close-coupling to an optical fibre.
  • the advantages are that IR is invisible and will thus give no false aimpoint cues to trainees, and using a "sweet-spot" device helps minimise the projected IR spot size.
  • the scenario (static background scene with static and/or dynamic targets) is projected on to a screen which is viewed, by the trainee, via the concave mirror.
  • the optical configuration allows each of five trainees to see a common wide field-of-view scenario, built up from five image sections generated by five computers, one at each firing lane. There is one aimpoint measurement system for each firing lane.
  • the mirror may be manufactured by any of several known methods, but a process avoiding direct working of the optical surface is preferred for reasons of economy.
  • a plastic film coated with a reflective layer may be attached to the specially profiled edges of a hollow box to form an airtight chamber. Withdrawing some of the air from the chamber causes ambient air pressure to force the film into a concave shape. This produces a concave mirror of a quality adequate for this application.
  • a servo system may be used to monitor the position of the centre of the mirror area and adjusts the pressure within the chamber to compensate for ambient pressure changes and film ageing thereby maintaining the required mirror radius.
  • This arrangement provides part-section training where a section would typically be 10 men. It allows 5 trainees to share the display and therefore train as a coordinated and interactive group.
  • Such an application is characterised by a much larger horizontal field of view requirement than the case of individual marksmanship training.
  • Such larger field of view requires that the input image be provided by optical projectors illuminating a screen. Either front or rear projection may be employed.
  • the trainees' vertical eyepoint movement may be constrained by the provision of a platform for the prone eyepoint position.
  • the trainee stands alongside the platform for firing from the standing eyepoint and lies on the platform for firing from the prone position.
  • a screen for front projection may be manufactured by any of several known methods, for example, by heating and pulling a sheet of acrylic over a mould of the correct radius followed by annealing. A diffusing coating can then be applied to the surface.
  • a 6 metre radius mirror is used preferably.
  • the height and width of the mirror are chosen to allow five standing and five prone positions laterally, and 700 mm vertically between the standing and prone levels. With such an arrangement, the field of view for each man is 11° vertically and 60° horizontally.
  • the concave mirror and the convex input image surface providing the original image or images are so arranged that a distant image of the input surface is viewable in the mirror from a plurality of vertically separate positions.
  • the projectors may provide images with movement therein.
  • each aimpoint measurement system comprises a coarse resolution detector, and four fine resolution detectors.
  • the aimpoint measurement system for each section must be able to determine which lane's IR LED generated each aimpoint.
  • the coarse resolution detector at each lane, is a CCD
  • CCD Charge Coupled Device
  • the CCD resolution is 752 x 582 pixels and produces a monochrome composite video signal.
  • Each video frame consists of an odd field followed by an even field, interlaced rasters being used.
  • the duration of each field is 20 milliseconds.
  • the four fine resolution detectors at each lane, use CCD cameras of the same type as the coarse detector. However, their individual lenses have a narrower field-of-view and they are arranged side-by-side, and each views one quarter of the main target area of the section of screen on which is projected the image generated by that lane's computer. To ensure a maximum vertical field-of-view resolution, the fine resolution detectors are mounted at 90° relative to the coarse detector, so that their raster lines are vertical.
  • the video signals from all five cameras are fed into an aimpoint detector unit which resides within the computer at each firing lane.
  • That computer also has a graphics unit, used to generate the display in the section of the scenario image for that lane, and an input/output (I/O) unit, which interfaces to the simulated weapon for that lane.
  • I/O input/output
  • the aimpoint detector unit can generate a video synchronisation signal which is fed into the external synchronisation inputs of all five cameras. Provision is also made for one of the aimpoint detector units to be operated in such a way that all cameras at all lanes are synchronised.
  • This unit is referred to hereinafter as the master unit.
  • the CCD cameras are sensitive to visible and IR wavelengths.
  • the scenario for each screen section is projected using a liquid crystal display (LCD) panel and a modified over-head projector (OHP) .
  • the OHP contains an IR blocking filter to minimise the IR content of the projected scenario.
  • a visible light blocking filter is placed in front of all the CCD cameras. This ensures that the CCD elements detect only the IR spot from the IR LED on each simulated weapon.
  • the visible light blocking filter is removed from the CCD cameras. This allows the CCD elements to detect pixel patterns projected by the computer display.
  • Each aimpoint detector unit resides on the motherboard 'AT' bus of a respective IBM compatible personal computer (PC) .
  • the unit consists of six main blocks: (i) a PC 'AT' interface, (ii) a video interface, (iii) a microcontroller and serial interface, (iv) a camera synchronisation control, (v) an inter-aimpoint unit synch, and (vi) an IR LED multiplexing control .
  • Figs. 1 and 2 illustrate a four lane small arms trainer embodying the invention.
  • Each lane includes a projector 11 for projecting one lane portion of an image onto a lane portion of a screen 12.
  • the projector 11 is controlled by a respective firing station 13 for that lane.
  • the composite image formed by the four lane portions projected onto the screen 12 by the four projectors 11 can be viewed by each of four marksmen 14 positioned in a respective lane behind the screen 12 and facing a curved mirror surface 15 supported by a mirror frame 16 and providing the marksmen 14 with a distant image of the image on the screen 12.
  • Each marksman 14 is equipped with a simulated or adapted weapon 17 that, when actuated, emits a beam of infra-red radiation having neglible divergence over the distance from the weapon 17 to the screen 12 via the mirror surface 15.
  • Masking 18 is provided at the peripheral regions of the mirror surface 15 to cut off highly distorted or distracting parts of the field of view of the marksmen 14.
  • Each lane is also equipped with an array of five infra ⁇ red sensing cameras 19 arranged to detect infra-red radiating emanating from the respective portion of the screen 12 on which the partial image projected by that lane's projector 11 is provided. Control signals are supplied to and video signals are received from the cameras of the array 19 by the respective firing station 13 of that lane.
  • Each firing station 13 is also in communication with an instructor station 20.
  • the four projectors 11 and the four arrays of cameras 19 are mounted in four lane sections of a floor frame template 21.
  • Fig. 1 the four marksmen 14 are shown using rifles 17 in the prone position, for which beds 22 are provided so that the marksmen 14 can view the mirror surface 15 as shown in Fig. 3A.
  • the marksmen 14 are shown using a variety of weapons 17 in a variety of positions. Suitable supports may be required, as illustrated in Figs. 3C and 3D, to allow the weapon 17 to clear the top of the screen 12 and to allow the marksman 14 to see the distant image provided by the mirror surface 15.
  • Fig. 4b shows a one lane part 23 of the floor frame template 21, which includes a projector mounting frame 24 for a projector 11, and a camera mounting frame 25 for a camera array 19.
  • Fig. 4a is a plan view of the screen 12, template 21, mirror surface 15 and mirror frame 16 of a five lane embodiment of the invention in which these parts are symmetrical relative to a centre line 26.
  • the -mirror surface 15 in this embodiment is formed by a Mylar sheet held in the required shape by a difference in air pressure between the atmosphere and the interior of the mirror frame 16, which for this purpose is equipped with a connection 27 to a vacuum pumping system (not shown) .
  • Fig. 5 is a simplified representation of an explanatory plan view of the centre lane of the five lane embodiment of Fig. 4a, like parts being given corresponding reference numerals.
  • the projector 11 consists of a light box 31, which is a modified overhead projector (OHP) , a liquid crystal display 32, a projection lens 33, and a light-path deflecting mirror 34. Representative light rays from the mirror 34 to the screen 12 and thence to the mirror surface 15 are shown.
  • a target position 35, at the mirror surface 15, is also shown with the path of infra-red radiation from the weapon 17 to the mirror surface 15 and thence back to the screen 12.
  • the target 35 is seen as lying within the partial image projected by the projector 11 of this lane, and therefore is within the field of view 36 of the camera array 19 of this lane.
  • the firing station 13 includes a firing station box 37 that controls the passage of compressed air from an air compressor 38, which supplies all the firing stations 13, to the weapon 17 to simulate recoil whenever the weapon 17 is actuated.
  • the firing box 37 is controlled by and acts as an interface between a personal computer (PC) 39 at the firing station 13 and the weapon 17.
  • the personal computer 39 controls the projector 11 and the camera array 19, and received video signals from the camera array 19.
  • the personal computer 39 also provides the signals that determine the image provided by the liquid crystal display 32, which may be a still image or a moving image.
  • Fig. 6a is a simplified axial section of the projector 11.
  • the light box 31 contains a tungsten bulb 41 serving as the light source.
  • a filter 42 is included between the liquid crystal display 32 and the projecting lens 33 to block infra-red radiation from the tungsten bulb 41 and allow visible light only to pass through to the lens 33.
  • the liquid crystal display 32 is provided with a connection 43 for video signals from the personal computer 39.
  • Fig. 6b represents the fields of view of the five cameras of the array 19.
  • One of the cameras referred to hereinafter as the coarse camera, has a field of view that corresponds to the whole field 36 and is rectangular with a horizontal to vertical ratio of 4:3.
  • Each of the other four cameras referred to hereinafter as the fine cameras, has a smaller field of view 40 with a horizontal to vertical ratio of 3:4.
  • the coarse camera is arranged to have scanning lines in the horizontal direction
  • each fine camera is arranged to have scanning lines in the vertical direction.
  • the fields of view 40 of the fine cameras are arranged contiguously side by side in the horizontal direction and together fill the horizontal dimension of the field of view 36 of the coarse camera.
  • FIG. 7 shows in a vertical section a weapon 17 in the form of a semi-automatic hand gun 50 adapted by the provision of an infra-red beam projector 51 and control and sensing electronics 52.
  • the beam projector 51 is secured to and axially aligned with the barrel 53 of the gun 50.
  • the electronics 52 are connected to the trigger 54 of the gun 50 and to an infra-red light emitting diode (LED) 55 of the beam projector 51.
  • LED infra-red light emitting diode
  • the projector 51 also includes a telephoto system consisting of a biconcave lens 56 and a biconvex lens 57.
  • the infra-red optical components of the beam projector 51 are shown in Fig. 8 and include in addition to the telephoto system 56, 57 a spherical ball lens 58 coupled to the LED 55.
  • Fig. 9 illustrates an infra-red beam projector for a rifle and has the telephoto lenses 56 and 57 adjustably mounted.
  • Fig. 10 is a schematic representation of the butt 61 and body 62 of a rifle-type weapon adapted for use in an embodiment of the invention. The weapon is equipped with the following sensors at the positions shown in Fig. 10: butt pressure load cell 63; cant sensing rotary potentiometer 64 with counterweights 65; automatic firing microswitch 66; magazine present microswitch 67; trigger position sensing linear potentiometer 68; gun-cocked condition microswitch 69; trigger-pulled condition microswitch 70; safety-catch condition microswitch 71.
  • Fig. ll illustrates principal signal paths ⁇ n the five lane embodiment of the small arms trainer of this invention.
  • the personal computer 39 sends signals to its projector 11 which in response projects a partial image onto the screen 12. Light from this partial image is reflected by the screen 12 to the mirror surface 15.
  • the weapon 17 is actuated by a marksman 14 (not shown in Fig. 11) and in response emits a beam of infra-red radiation towards the mirror surface 15 which reflects the radiation to a point, in the field of view of the camera array 19 in this example, on the screen 12.
  • the camera array 19 in response supplies positional data to the personal computer 39.
  • All five personal computers 39 are connected to an RS 485 serial link 75 for exchanging data relating to the actuation of weapons 17 and the position of infra-red radiation spots sensed by the camera arrays 19. Also each personal computer 39 is in communication with the instructor station 20 through a further RS 485 serial link 76 and a parallel bus 77. Fig. 12 illustrates the buses 75,76 and 77 and the connection to the personal computers 39 and the computer 80 at the instructor station 20.
  • Fig. 13 shows the personal computer 39 of one lane connected to the liquid crystal display 32, the camera array 19, the firing box 37, and the buses 75,76 and 77.
  • the firing box 37 interfaces the personal computer 39 with the weapon 17 and with a headset 81 for the marksman (not shown) using the firing station
  • the headset 81 is supplied with audio signals from the personal computer 39 through the firing station box 37. Audio signals can be supplied from the instruction station 20 through audio lines in the parallel bus 77 to the personal computer 39. Further audio signals may be generated at the personal computer 39 to correlate with actuation of the weapon 17. An instructor at the instructor station 20 may speak to the marksman, and background noises may be generated through the operation of the audio circuitry thus coupled to the headset 81.
  • Fig. 14 shows the connection of a twenty-four volt power supply unit 82 to the personal computer 39, the firing station box 37, and the camera array 19, and the connection of a twelve volt power supply unit 83 to the camera array 19.
  • An a.c. power line 84 is connected directly to the computer 39 and the light box 31, and through a power unit 85 to the liquid crystal display 32.
  • Fig. 15 represents slots for circuit cards at the back of the personal computer 39 of a firing station. Ten slots, designated A to K, are indicated. Circuits at slots A to E and J are connected as indicated by the letter A to E and'J in Fig.
  • a video circuit card in part of slot G is connected to the liquid crystal display 32. Slots K, H and F are not used.
  • Fig. 16 represents a panel 110 of five press button switches 111 to 115.
  • the status of each of these switches 111 to 115 is polled by the personal computer 39, which takes appropriate action on detecting that the polled switch is in the actuated condition.
  • the action taken by the personal computer 39 is determined by its software.
  • Fig. 19 shows a weapon interface unit 90 mounted in the firing station box 37 and interfacing between the weapon 17 and the personal computer 39.
  • the weapon includes a weapon identity unit 91, which indicates the type of the weapon 17, and may be in the form of a preset multiposition switch.
  • the unit 90 includes buffer amplifiers 92 and 93 for the trigger position and cant sensors 68 and 64, a differential amplifier 94 for the butt pressure sensor 63, and a weapon recoil controller 95 consisting of a microcontroller 96, a 12 megahertz clock 97, a recoil air on solenoid 98, and a recoil air off solenoid 99.
  • the solenoids 98 and 99 control the supply of compressed air to the weapon 19 to simulate recoil.
  • the input signals to the microcontroller 96 are the trigger pulled signal from the sensor 70 indicating the status of the trigger, the cocked, automatic, and identity signals from the sensors 66,69 and 91, and a fire inhibiting signal from the personal computer 39.
  • Fig. 20 illustrates equipment at the instructor station 20.
  • the computer 80 which is a personal computer, has a keyboard unit 101 allowing an instructor to enter control data, a printer 102 for providing hard copy records; a monitor 103 for presenting a display to the instructor and a headset 104 for the instructor.
  • the headset 104 allows the instructor to speak to and listen to the marksmen 14 using the trainer over the audio lines included in the parallel bus 77.
  • Fig. 21 shows the instructor station equipment of Fig. 20 with connections to the a.c. power line 84. ' Separate audio connections are indicated for the headset communications and background noise supplied from the instructor station computer 80 to the headsets 81 (Fig. 14) of the trainee marksmen.
  • Fig. 22 represents slots for circuit cards at the back of the personal computer 80 of the instructor station.
  • Ten slots, again designated A to K, are indicated, and these slots correspond to the ten slots represented by Fig. 15.
  • part of slot K may be used for circuits to be connected to a mouse
  • the slot J houses circuits connected to the keyboard 101
  • part of slot G houses circuits connected to the printer 102 and the other part houses circuits connected to the monitor 103
  • slot F houses circuitry for generating background noise, with a connection to the audio communications bus 77 as indicated in Fig. 21
  • slot E houses an RS 485 circuit card which is connected to the bus 76
  • slot C houses a communication circuit card that is connected to the audio communications bus 77.
  • the headset 104 is also connected to the communications circuit card in the slot C.
  • the PC 'AT' interface 120 consists of 32 bytes of RAM 121 which is dual ported between the PC 'AT' bus 122,123 and the microcontroller 124 through transceivers 125 and 126.
  • the dual port RAM 121 is I/O mapped on the PC bus 122 and the base address is set by means of a hex-switch 127.
  • the base address may be set to any 256 byte boundary in the range OOOOH to OFOOH and should be set to 0300H minimum.
  • the setting of the hex switch 127 is compared with address bits 6 to 13 and a control line on bus 122 by a comparator 128.
  • the PC 39 may interrupt the on board microcontroller 124 (start of frame) by writing to I/O port at base address +21H.
  • the PC 39 may reset the aimpoint detector unit by writing to I/O port at base address +20H.
  • the microcontroller 124 used is an Intel 80C152 which is an 8051 core with on-board hardware for direct memory access (DMA) and a high speed serial channel. External to the microcontroller 124 there are 64K bytes of EPROM 129 and 32K bytes of RAM 130.
  • DMA direct memory access
  • the serial interface provides synchronous communciations at 1.0 Mbaud over the multi-drop bus 75 conforming to RS-485.
  • the RS-485 bus 75 consists of a differential signal pair and ground. Communication is half duplex with a single master and four slaves, (iii) Video Interface 131
  • the video interface 131 accepts inputs from five video channels : four channels 132 to 135 from the four fine resolution cameras and one channel 136 from the one coarse resolution camera. Each video channel has a vertical counter and a horizontal counter which operate synchronously with the video input to locate the IR LED spot position. In addition, the four fine resolution channels 132 to 135 have an extra counter to measure the IR LED spot width.
  • Each weapon aimpoint unit provides the camera synch control signals for its own five cameras.
  • the unit provides horizontal, vertical and composite synchronisation signals at both video and TTL levels.
  • the signals come from a video synchronisation generator integrated-circuit (IC) 138 which is free running.
  • IC video synchronisation generator integrated-circuit
  • a TTL link 139 is provided which allows all the weapon aimpoint units to be synchronised. Inter-unit synchronisation is achieved through the multi-drop bus 139 which employs buffered versions of the signals described in (iv) .
  • the master unit generates a pulse which interrupts the master unit itself and all the slaves.
  • the source of the interrupt is the field signal from the synchronisation generator 138.
  • Each of the five IR LEDs may only be turned on once every 200 milliseconds, and is on for a maximum of one 40 ms video frame ie for 20 ms for both the odd field and the even field in that frame. Since all the units are synchronised they can determine when they may switch on their IR LEDs by counting synchronising interrupts .
  • An on-board timer generates a timing reference interrupt which allows the microcontroller 124 to achieve the modulation function.
  • the IR LED is controlled by a TTL signal on a line 141. Circuit Operation
  • the microcontroller 124 polls a register in which a bit is set when a channel detects an IR spot. There is a unique bit in that register for each channel. The microcontroller 124 reads the counts and stores the values away. Since the spot may extend over several lines, several sets of values may be stored for a single spot. The spot may be present in any part of the camera's field of view, so detection cannot be guaranteed until the end of the video frame. At the end of the video frame the microcontroller 124 resolves any occurrences of a spot being detected by more than one channel and calculates the centre point of the spot.
  • the aimpoint units Since all the aimpoint units know when each IR LED is switched on, they can determine the originator of a detected spot. If the aimpoint unit detects its own spot then the spot information is written in the dual port RAM 121 for the PC 39 to read. If the spot belongs to another lane then the information must be sent back, over the serial link 75, to that lane's computer.
  • Serial transfers may only be initiated by the master unit. If a slave unit has spot data which must be communicated to another lane it waits until it is polled by the master unit before sending the spot data.
  • the master unit polls the slave units in sequence.
  • the act of polling a slave unit allows it to become the bus master, so that the slave unit can transmit information to any other unit.
  • the master unit (lane number one) can detect when information has been sent and broadcasts an end-of-updates message.
  • Aimpoint spot data is made available to the PC one frame after it was detected, irrespective of whether it originated at the local or a remote aimpoint unit.
  • Each aimpoint detector unit uses the following memory-mapped I/O:
  • the X and Y co-ordinates are 12 bit words.
  • the video channel number which detected the spot is encoded into the top three bits of the high byte for both X and Y.
  • the visible light blocking filters are removed from the CCD cameras during this callibration process.
  • the aimpoint measurement system can be applied to any situation where the point of incidence of a light source on a plane is to be measured.
  • the aimpoint solution will work with a wide range of alternative display systems; it does not need a collimating mirror display.
  • the small arms trainer (SAT) of Figs. 4 and 5 provides weapons training in two modes:
  • Advanced marksmanship trainer mode Five marksmen are provided with a scenario in which they act as a team to hit designated targets.
  • Two five-lane systems can be used in unison to provide ten lanes.
  • the five lane trainer is as shown in Figs. 1, 2, and 3 but has an extra central lane.
  • the SAT is controlled by an instructor via an instructor's operating station (IOS) .
  • IOS instructor's operating station
  • a number of pages are displayed at the IOS to permit the instructor to control the SAT and to monitor the trainee marksmen.
  • a 'Marksman' may also be referred to as a 'firer'.
  • the target image is generated by five sets (one for each lane) of one personal computer (PC) , one overhead projector (OHP) light box, one liquid crystal display (LCD) , and one lens, a screen, and a mirror.
  • a vacuum pump is used to maintain the mirror shape.
  • the five PCs are connected to each other and to the IOS by two networks.
  • Each marksman uses a modified gun (several different types are provided) .
  • the gun emits an infra-red beam, which is detected by an array of cameras in the vicinity of each image generator.
  • the infra-red beams are time multiplexed such that at any instant only one gun emits a beam.
  • the camera outputs are used by the PC to determine whether the gun which is currently emitting a beam has hit the target.
  • Sensors in the gun inform the PC of various parameters such as its cant and the force on the butt. These parameters are available for display at the IOS.
  • a pneumatic system provides simulation of the gun recoil.
  • Gun sounds are simulated by a circuit card located in the PCs. This card also permits communication between instructor and marksmen via headsets .
  • the SAT consists of the following major assemblies: Mirror and screen.
  • FSs firing stations
  • Image projection equipment (light box, LCD, lens) and coarse and fine infra-red detection cameras.
  • the mirror 15 is 2 metres high and is tilted forward, as shown in Fig. 3, so that its centre of curvature is on the floor, the radius of curvature being about 6 metres .
  • the mirror 15 has an active area of approximately 72° horizontally and measures 11m from corner to corner.
  • the vertical field of view is 11°. It is made of aluminum-coated Mylar which is stretched over a wooden frame 16.
  • a vacuum pump exhausts air from the frame 16 to hold the Mylar against the frame 16 and thus maintain the shape of the mirror 15 which is approximately spherical.
  • the screen 12 is made of wood and has a neutral gain surface. Although the screen 12 is preferably spherical, a conical surface is used in practice.
  • the image is projected onto the screen 12 and is then reflected onto the mirror 15, which provides a distant image for the marksman.
  • the screen 12 is nearer to the mirror 15 than its paraxial focal surface.
  • the marksman stands behind the screen 12 or, if prone, lies on a prone bed 22 which elevates him above the level of the screen 12. Power supplies
  • the two dc power supply units 83 and 82 are located in the screen assembly; 12V for the cameras and 24V for the firing station box compressed air actuators. Projector and Camera Installation Projector (Fig. 6A)
  • AMT mode Five image generators (projectors) are mounted below the mirror 15. In BMT mode they provide individual images for each firing lane; in AMT mode they provide a contiguous image over the surface of the screen 12.
  • the overhead projector (OHP) light box 31 sends a beam of light through a thin film transistor (TFT) liquid crystal display (LCD) panel 32.
  • TFT thin film transistor
  • LCD liquid crystal display
  • a 640 x 480 pixels colour image is generated on the LCD 32 by the firing station PC 39.
  • This image is passed through an adjustable lens 33, and is then reflected onto the screen 12 by a small fixed mirror 34, for subsequent reflection onto the Mylar mirror 15.
  • An infra-red filter 42 removes infra-red from the image to enable the aimpoint detection cameras 19 to operate correctly.
  • the gun 17 emits an infra-red beam of light to indicate the position of its aimpoint.
  • Sony charge-coupled device (CCD) cameras 19 are positioned below the mirror 15 to view the screen 12, one array 19 of five cameras for each lane, to detect the infra-red beam which is reflected by the mirror 12 onto the screen 12.
  • the camera outputs are sent to the weapon aimpoint (WA) card in the PC 39; this card (referred to hereinbefore as the aimpoint detector) also provides a sync signal for the cameras.
  • WA weapon aimpoint
  • the infra-red emission is sequenced so that only one gun is emitting at any instant. If the cameras 19 of one lane detect an infra-red beam, but that lane's gun 17 is not emitting, the firing station PC 39 sends a signal over the RS485 link 75 to the other firing station PCs 39. The PC 39 associated with the firing station from which the emission originated is therefore informed of the weapon aimpoint .
  • the firing station PC 39 correlates the position of the infrared beam with the target image display data and with instructor-inserted variables, to determine the fall of shot and whether or not the target is hit.
  • Two types of lenses are fitted to the cameras 19.
  • One camera views the whole of the lane to supply a coarse position of the weapon aimpoint.
  • Four cameras each view part of the centre strip of the image (most targets and therefore aiming occurs within this strip) to supply a fine position of the weapon aimpoint, as illustrated in Fig. 6B.
  • a filter ensures that the cameras 19 only detect infra-red.
  • Each camera has a resolution of 752 x 580 pixels.
  • Firing Station ( Figures 13, 14, 15, and 16)
  • Each firing station consists of:
  • a firing station box is
  • the PC 39 has a 486 DX 66 MHz configuration with six expansion ports. No keyboard or monitor are provided. To permit the PC 39 to boot-up when power is applied, a keyboard emulator is provided within the firing station box 37.
  • the VGA monitor circuit output (slot G) is used to drive the projector installation LCD display 32.
  • the PC 39 incorporates the following special circuit cards :
  • a weapon aimpoint (WA) card (Figs. 18A and 18B) , which provides the interface with the cameras 19, and sequences the infra-red beam from the gun 17.
  • the RS485 serial data bus 75 transfers aimpoint data between the WA cards in each PC 39.
  • a communications card (Fig. 17) , which interfaces with the communications headset, and which generates gun sounds.
  • the PC also incorporates :
  • An I/O card (slot A) , which provides the interface with the gun (via the firing station box 37)
  • Machine gun (7.62mm) .
  • LRAC anti - tank
  • Each gun 17 is fitted with actuators and sensors to allow the following parameters to be controlled and observed (see Fig. 10) :
  • the gun contains a compressed air actuator to allow simulation of recoil, and an eye-safe (infra-red) light source for aimpoint tracing.
  • a compressed air actuator to allow simulation of recoil
  • an eye-safe (infra-red) light source for aimpoint tracing.
  • the FS PC supplies one signal to the firing station box to disable the recoil. This simulates jamming of the gun, and occurs when the gun malfunction is enabled by the instructor at the IOS.
  • the light source is modulated by another signal from the PC.
  • Each gun consists of a real weapon which has been extensively modified to:
  • the infra-red modulation signal, gun status signals, and compressed air supply all pass through the firing station box.
  • the electrical cable and air pipe are combined into a single umbilical, with separate electrical and air connectors at the firing station box end.
  • Infra-red Beam (Figs. 7, 8 and 9)
  • the infra-red beam is produced by a light emitting diode (LED) 55.
  • the LED 55 is modulated on and off by a signal on line 141 from the weapon aimpoint (WA) card (Figs. 18A and 18B) in the PC 39 of the appropriate lane.
  • the LED 55 is mounted in a tube which is mounted onto the gun barrel, below the sight.
  • the tube incorporates one concave lens 56 and one convex lens 57...
  • the LED 55 and lens assembly 56,57 is prealigned at the factory; if the LED 55 fails, the complete tube assembly is replaced.
  • Figure 10 shows the locations of status transducers in a typical gun (the exact configuration varies depending upon the weapon type) .
  • Trigger pulled (gun fired signal) .
  • Burst mode (eg., 3-shot burst) selected. Not applicable to all weapon types.
  • Weapon identification This consists of a four-bit code, hard-wired inside the gun connector, which identifies the type of weapon being fired.
  • This signal is produced by a rotary potentiometer. Counterweights are fitted to the potentiometer so that when the gun is rotated to left or right around it sighting axis (line of sight) , the potentiometer wiper moves accordingly.
  • Trigger position (snatch) . This signal is produced by a linear potentiometer.
  • Butt pressure This signal is produced by a load cell, and indicates the amount of force with which the weapon is being held. This parameter is not applicable to anti-tank weapons.
  • a ⁇ 5V supply provides the reference for the analog transducers, and the transducer outputs therefore have a bipolar 5V range.
  • the compressed air supply is received at a pneumatic cylinder which is built into the gun and replaces part of the gun structure.
  • One solenoid in the firing station box selects the compressed air on, and the other off, in response to a command from the PC. Two solenoids are required to ensure a fast on/off cycle. If the gun jammed malfunction is selected by the instructor, no recoil is simulated when the gun is fired.
  • the firing station (FS) box 37 provides the main interface between the marksman and the SAT. It measures 350 x 180 x 100mm and is painted black. Each lane has its own FS box 37, raised on a stand approximately 450mm high.
  • the firing station box 37 has the following functions:
  • switches 111 to 115 Provides five switches 111 to 115 (GO,TARGET,TRACE, ZERO, and CALL (CALL is indicated by a telephone handset) ) which allow the marksman some control over lessons and practices.
  • the CALL switch illuminates red, and the other switches illuminate green.
  • the switch panel is shown in Fig. 16.
  • the FS box 37 therefore incorporates the following items:
  • Front panel connectors for the gun I/O, the gun compressed air, and the marksman's headset are front panel connectors for the gun I/O, the gun compressed air, and the marksman's headset.
  • Rear panel connectors for a keyboard the I/O interface with the PC, and the compressed air supply from the compressor.
  • the instructor programs the required lesson/scenario/ practice, and a default landscape is displayed.
  • a default landscape is displayed.
  • the marksman is ready to fire, he operates the GO switch to display the scenario.
  • the TARGET, TRACE, and GO switches are enabled:
  • TARGET displays a close-up of the target; GO then returns to the scenario.
  • TRACE displays the trace history of the last five rounds
  • ZERO adjusts the gun sights in accordance with calibration shots fired by the marksman.
  • the offsset is used in subsequent aimpoint calculations.
  • the headset 81 allows two-wayvoice communication between the marksman and the instructor.
  • the marksman can initiate communication with the instructor by operating the CALL switch 115 on the firing station box 37.
  • the instructor can communicate with the marksman at any time through his own headset 104. Aural cues
  • Aural cues are generated on the firing station PC communications card (Fig. 17) and in the instructor station 20 on a soundblaster card (background battle sounds) in response to digitally stored data, and are replayed to the marksman via the communications headset.
  • Digitally stored sounds are read out and converted into audio signals in real time. Also, analog audio sources may be linked in through the soundblaster card.
  • Instructor Station 20 Voice communication remains audible when aural cues are present. Instructor Station 20
  • the instructor's operating station (IOS) 20 consists of a 486 DX 66 MHz PC 80 with six expansion ports, together with a monitor 103, keyboard 101, printer 102, and communications headset 104.
  • FIG. 20 A block diagram of the IOS is given in Figs. 20 and 21.
  • the rear of the PC 80 is shown in Fig. 22.
  • the PC 80 incorporates a communications card (slot C) , which interfaces with the communications headset 104.
  • slot C a communications card
  • the PC 80 also incorporates:
  • the soundblaster card (slot F) , which generates aural cues (battle sounds) .
  • the monitor 103 displays a suite of nine IOS pages, which enable the instructor to control and monitor the SAT.
  • the pages are called to the monitor 103 by function keys (not shown) F2 through to F10 on the keyboard 101.
  • the keyboard 101 is then used to select the state of instructor-controllable parameters on these pages; when all desired parameter edits have been made, function key Fl is operated to enter the edited parameters into the scenario (Fl is the GO command) .
  • a hard copy of the currently displayed IOS page can be obtained at the printer 102.
  • Main - This module is entered from DOS, and performs initialization of the interfaces and memory. This module also calibrates the detector system.
  • This module collates and stores the inputs from the weapons transducers .
  • FS Display - This module contains a handler for the FS PC VGA card. It obtains and displays specified scenarios, overlay targets and prompt information.
  • This module handles reception of aimpoint data from the cameras by the WA card.
  • this module calculates fall of shot from ballistic information, gun transducer inputs, and instructor-controlled conditions.
  • FS Result proc This module receives the output from FS Firing calcs. It then uses the target data base to calculate the fall of shot on the target, or the miss indication, for each round of fire. This module also calculates the group size and mean point of impact (MPI) at the completion of each practice. When the marksman operates the ZERO switch at the FS box, this module performs the electronic zeroing of the sights.
  • MPI mean point of impact
  • This module contains the handler for the FS box interface .
  • FS Headset This module controls the sound playback hardware, and the mixing of aural cues and voice communications.
  • FS IS interface - This module contains the handler which contains the RS485 link between the FS PCs 39 and the IOS 20.
  • the muzzle of the weapon 17 is on a horizontal line to the detected aimpoint (point of incidence of the IR beam on the image) .
  • the ballistics are those of the specific weapon 17 and assumed ammunition.
  • the distance from the muzzle to the target is given.
  • a standard stationary target representing a circular board of 1.22 square metres at 100 metres from the muzzle is presented and the marksman is required to fire five shots at its centre. It is assumed then that the average of these five shots is within a defined central region of the target, and from this assumption and the detected positions of the corresponding five aimpoints, the direction of the marksman's sighting axis (line of sight) for the weapon being used is calculated from the assumed ballistic and target distance and position data. This sighting axis data is used in subsequent calculations of fall of shot.
  • An additional program performs an auto-calibration routine.
  • the message DO YOU WANT TO CALIBRATE THE SYSTEM? is displayed at the IOS. If YES is selected, all PCs enter their calibration mode and pixels are displayed on the screen. The pixels are recorded by the cameras. Fifth order polynomial coefficients are then calculated to compensate for differences between the expected positions of the pixels and the positions calculated from the camera images. The coefficients are output to disk file and to PC memory; when a PC completes this routine it issues a complete flag, and when all PC's have completed the routine the system enters real time. If NO is selected in response to the calibration message, all PCs load the coefficients from a disk file, issue the complete flag, and when all loads are complete the system enters real time. OPERATION
  • the SAT operates in the following manner:
  • the IOS and firing station PCs When power is applied, the IOS and firing station PCs automatically boot up, and the vacuum pump and air compressor operate.
  • the instructor uses the IOS pages to set up the required training scenario.
  • a default landscape is displayed on the mirror.
  • the marksman When the marksman is ready to commence firing, he operates the GO switch at the firing station box. Targets are then displayed in accordance with the scenario selected by the instructor.
  • Gun parameters are sent to the firing station PC.
  • the marksman pulls the trigger a gun sound is heard via the communications headset, and the compressed air actuators operate to produce the gun recoil (unless the instructor has selected the gun jam malfunction, in which case no recoil occurs) .
  • the PC 39 pulses the infra-red aimpoint beam, and monitors the cameras in sequence. If a beam is detected by the cameras 19, the PC 39 checks whether the gun infra-red beam is currently pulsed on.
  • the aimpoint data is transferred to the other firing station PCs 39. If the beam is on, the PC 39 calculates where the shot has fallen, and interrogates the target database to determine whether the target has been hit.
  • Each firing station personal computer 39 generates an image or part of an overall image by using its projector 31.
  • the computer combines a background scene, which extends over the whole field of the projector 31, and a target picture which is positioned in and occupies only a part of the field of the projector 31.
  • Both the background scene video data and the target video data may be obtained by digitising photographs. Digitised backgrounds and targets are stored in separate files in the memory of the computer 39.
  • the position of a target in projector pixel coordinates is known from the selection of its position within the background scene. It can also be arranged that a target move from position to position within a background scene, animation techniques being used for this purpose.
  • the operation of calibration provides a mapping between the projector pixels and the . camera pixels so that the calculated position of a shot by the marksman can be related to and compared with a target position.
  • Weapons Aimpoint Card Figures 18A and 18B
  • the weapon aimpoint (WA) card performs the following functions :
  • One WA card is present in each firing station PC 39. ' The cards communicate with each other by means of the RS485 serial link 75. If one WA card sets its infra-red beam on, and the resultant video image is received by a second WA card, the first card is informed of the beam position by the second card so that its PC 39 can determine the shot fall (aimpoint) and whether or not the target is hit.
  • the weapon aimpoint circuit card incorporates the following circuits:
  • Microcontroller 124 The Microcontroller 124.
  • Infra-red driver 140
  • the card incorporates an LED (not shown) that illuminates red if the infra-red modulation fails.
  • the card incorporates field, line, and composite sync termination resistor straps which terminate the inter-card sync bus 139, and must be made for the two cards at either end of the bus 139, and left open for the other cards.
  • An RS485 serial link termination resistor strap terminates the inter-card aimpoint data link 75, and must be made for the two cards at each end of the bus 75, and left open for the other cards .
  • This circuit interfaces the card to the PC data and address busses 123,122. Data transfers occur via the 32 byte dual port RAM 121; the PC 39 has access to the RAM 121 at one port, and the microcontroller 124 has access at the other port.
  • a PAL logic array 142 controls the access with respect to read and write signals 143,144 from the PC 39 and from the microcontroller 124, and with respect to address comparison between the PC address bus 122 and the hexadecimal switch 127.
  • the switch setting matches the address bus status, data on the PC data bus 123 is intended for the WA card (the switch setting is the base address of the RAM 121) .
  • Operation of the microcontroller 124 is determined by firmware located within the 64 k-byte PROM 129.
  • the microcontroller 124 receives 8-bit output data from the camera video decoder circuit 131 through a transceiver 145 and then calculates the infra-red beam's location within the video image.
  • the microcontroller 124 controls modulation of the infra-red beam. If the card detects infra-red in the video image and the beam was not fired from this card, the microcontroller 124 sends beam position data over the RS485 serial bus 75 to the other WA cards. It also receives data from the other WA cards when this card activates the beam but another card detects it in its video signal. If the beam was sent from this card, the card informs the PC 39 via the dual port RAM 121.
  • the RAM 130 serves as a datastore and workspace for the microcontroller 124.
  • a buffer 160 is connected to an 8-bit address and data bus 161 of the microcontroller 124 and is used to build up complete addresses on the address bus 151 in accordance with Intel technique for the microcontroller 124.
  • the RS485 multidrop bus 75 provides synchronous communication at 1.0 Mbaud and consists of a differential signal pair and a ground. Communication is half duplex, with a single master and four slaves. Serial transfers are initiated by the master, and any slave with information to send waits until the master card requests that it be sent.
  • the microcontroller 124 also produces a three-bit shutter code for use with cameras which have a controllable shutter. This code can be supplied through the PAL 142 and a level shifter circuit 147. SYNC GENERATOR 137
  • Field, line, and composite synch signals are produced by a sync generator 138 and are bussed to the other WA cards via a level shifter 146 provided that the MASTER signal is set active by the microcontroller 124. If MASTER is inactive, the card receives these sync signals via the bus 139 from the WA card on which MASTER is active.
  • the sync generator 138 generates its signals as for standard television and may be an SN74LS590 integrated circuit as manufactured by Texas Instruments, Inc.
  • the level shifter 146 includes switching circuitry controlled by the microcontroller 124.
  • each WA card uses its own sync generator field, line, and composite sync signals to provide a sync signal for the cameras.
  • the SAT is in AMT mode (all lanes are combined to produce one contiguous image) the WA cards need to be in sync with each other, and the camera sync is then derived from the card on which MASTER is active. In both cases a single, common sync signal is sent to all five cameras in an array 19.
  • the sync signals are output in two formats; one at video levels and one at TTL levels.
  • INFRA-RED DRIVER 140 INFRA-RED DRIVER 140
  • Two of the three counters within a programmable interval timer (PIT) 148 are used to generate the infra-red modulation signal.
  • One counter produces an offset from the start of the video field, and the other counter determines the length of time for which the infra-red beam is switched on.
  • the PIT counters are programmed from the microcontroller data bus 149.
  • the PIT output is routed to a PAL 150, which sets the infra-red beam on or off in accordance with the state of an enable signal from the microcontroller 124. To ensure that only one card sets its infra-red beam enable active at any time, each card counts the number of video fields and uses this count to determine when it can turn its beam on. The cards synchronize their beam counts via the TTL link 139.
  • the microcontroller address bus 151 is connected to the PIT 148 and the PAL 150 as shown.
  • the video interface receives five video inputs 132 to 136, four from fine resolution cameras and one from a coarse resolution camera.
  • the sync signals are separated out by separators 152 and taken to line and pixel counters run at line and pixel rates within logic cell array (LCA) devices 153, 154, 155; the counters operate synchronously with the video input to locate the position of the infra-red beam.
  • the LCA counters are driven by a 20 Megahertz clock 159. The counters halt when a beam is detected, and store the count values for subsequent transfer to the microcontroller 124.
  • the microcontroller 124 calculates the centre point for each spct and averages the centre points for the odd and even fields.
  • the four fine resolution channels 132 to 135 incorporate an extra pixel counter to measure the infra-red beam spot width.
  • the PAL 150 generates five enable signals 162, which are supplied one each to the five comparators 156 so that the comparators are enabled when the infra-red drive is active on line 141.
  • the infra-red beam spot is detected by comparing the video input with an adjustable threshold at a comparator 156.
  • the spot produces a peak in the video input.
  • the comparator threshold is set by the microcontroller 124 via a digital-to-analog converter (DAC) 157.
  • Video amplifiers 158 are included as indicated.
  • a Weapon Aimpoint Card is installed in the Firing Station PC 39 of each lane of a SAT system.
  • the purpose of the card is to provide the Firing Station PC 39 with the weapon aimpoint location, in camera co-ordinates, of its own weapon.
  • the aimpoint location is detected using the CCD video cameras, five of which are pointed at the projector screen 12 for each lane.
  • the card determines the aimpoint location by examining the video signals from the CCD cameras 19.
  • the card controls its five CCD cameras 19 so that the video signals it receives are always synchronised. It also controls the IR beam projector on the weapon 17 in its own lane so that it can be turned on at the appropriate time in the CCD cameras' video frame.
  • the system can operate in two modes.
  • each lane is considered to be separate, and the trainee may only fire at targets in his own lane. In this mode there is no communication between Weapon Aimpoint Cards and an aimpoint location is produced every video frame.
  • each lane forms part of the overall scenario.
  • the trainees may fire at targets in any lane. Since the system must be able to determine which aimpoint location belongs to which weapon, all the Aimpoint Cards (and hence all the CCD cameras) are synchronised.
  • the IR projector on the weapon 17 for each lane is switched on in turn, for one video frame in every five.
  • the card which calculates an aimpoint location can determine which lane originated the IR spot by counting video frames.
  • the aimpoint location is sent to the lane which originated the spot over the RS-485 serial link 75, which joins all the Weapon Aimpoint Cards.
  • the circuit consists of six main blocks - the PC interface, the video interface, the video counters, the microcontroller and serial interface, the camera sync control, the IR projector modulation control and the inter card sync. Sequence of Events for Weapon Aimpoint Card in AMT Mode
  • Any Aimpoint card can send previously calculated spot co-ordinates to whichever Aimpoint card originated that spot.
  • spot co-ordinates have been received from another card over the serial bus, or if spot co-ordinates have been calculated by this card, then write them into the dual port RAM 121 that can be read by the PC 39. Also write the lane number and channel number (which camera) that detected the spot.
  • Video threshold AMT/BMT, IR spot intensity
  • the source of the interrupts is the sync generator circuit 138. Data from the coarse camera is ignored if data from a fine camera is available.
  • the PC interface consists of 32 bytes of RAM 121 which is dual ported between the ISA bus 122 and the microcontroller 124.
  • the dual port RAM 121 is I/O mapped on the ISA bus 122 and the base address is set by means of the hex switch 127.
  • the base address may be set to any 256 byte boundary in the range OOOOh to OFOOh and should be set to 0300h minimum.
  • An ISA address match is determined by comparator 128. All ISA bus signals are buffered so that the card only presents one load to the bus.
  • the dual port RAM 121 is controlled by PAL 142 which is a MACH210. When the ISA bus makes an access, its buffers are enabled if the RAM 121 is free. If not, PAL 142 issues a WAIT command through level shifter 147 to put the bus in wait states until the RAM- 121 is free.
  • the microcontroller 124 accesses the RAM 121 by first making a request. If the RAM 121 is free, PAL 142 responds by enabling buffers 228 so that the microcontroller 124 can complete its access.
  • the PC 39 may interrupt the on board microcontroller 124 by writing to I/O port at base address + 21h, which causes the signal on an interrupt line to pulse low.
  • the PAL 142 controls the card reset functions.
  • a power up reset is derived from a resistor and a capacitor, which may also be operated manually.
  • the card is also reset when an ISA bus reset signal is high.
  • the PC 39 may reset the card by writing to I/O port at base address +20h. Microcontroller + Serial Interface.
  • the microcontroller 124 used is an Intel 80C152 which is an 8051 core with on board hardware for DMA and a high speed serial channel. External to the microcontroller 124 there are 64K bytes of EPROM 129 and 32K bytes of RAM 130. The microcontroller 124 is driven by a 12 megahertz clock 163.
  • the serial link provides synchronous communications at IMbaud over a multidrop bus conforming to RS-485.
  • the RS-485 bus 75 consists of a differential signal pair and ground. Communication is half duplex with a single master and four slaves.
  • the serial bus 75 should be terminated at lanes 1 and 5 with a jumper.
  • the video signal is terminated with a 75 ohm resistor and AC coupled to the video sync separator 152.
  • the sync separator 152 extracts timing information from the video signal.
  • the video signal is also AC coupled to wideband op-amp 158 which has a gain of 12.
  • the amplified video signal is connected to comparator 156 where it is compared with the threshold signal. Due to the optical filtering arrangement used on the SAT system, the amplified video signal will only be greater than the threshold signal for parts of the video waveform that contain an IR spot. When this occurs the output of the comparator 156 goes low.
  • the threshold signal level is set by D/A converter 157 under the control of the microcontroller 124, and is common to all the video input channels.
  • LCA 153 contains the counters for channels 1 and 2
  • LCA 154 contains the counters for channels 3 and 4
  • LCA 155 contains the counters for channel 5 along with some status registers and address decode circuitry for decoding addresses, sent by the microcontroller 124 over the bus 149, into select and control signals which LCA 155 then places on a bus 231 linking all three LCA' s 153, 154, 155.
  • the counters for each channel operate identically.
  • X and Y directions are relative to the CCD camera.
  • the Y counter counts video lines. It is reset at the start of a video field. Whenever a spot is detected the current count is transferred to a store where it may be read by the microcontroller 124. The Y counter produces a 9 bit count.
  • the X counter is an 11 bit free running counter which is clocked at 20 MHz from the clock 159. At the start of each video line the counter is reset. As soon as a spot is detected the counter is halted. At the same time a 6 bit free running counter (the W counter) is started. It continues to count at 20 MHz until the spot is no longer present, thus giving a measure of the spot width. When the W counter is halted both the W and X counts are stored so that they can be read by the microcontroller 124. At the same time a signal is pulsed low, setting a bit in a status register in LCA 155 to indicate that channel 1 has acquired spot data.
  • the IR spot extends over several video lines.
  • the microcontroller 124 reads the W, X and Y counts for each line on which the spot occurs so that it can calculate the spot centre.
  • Each weapon aimpoint card provides the camera sync control signals for its own five cameras.
  • the card provides HD, VD and CS signals at both video and TTL levels.
  • the signals come from the sync generator ic 138 on the card in BMT mode or from the inter card sync bus 139 in AMT mode.
  • the cards are synchronised by means of a multidrop bus containing the TTL level signals.
  • the inter card sync signals are driven/received by a transceiver in the level shifter 146.
  • the master card In AMT mode the master card (lane 1) drives these signals from its sync generator 138 onto the bus 139.
  • the slave cards use these signals to provide camera sync and for internal timing.
  • the sync bus 139 should be terminated at lanes 1 and 5 with jumpers.
  • the IR projector is powered from the Weapon Aimpoint Card.
  • the line 141 controls +5V power and a switched ground.
  • the IR projector is turned on at the start of a video field and kept on for a length of time determined by a counter/timer. Operation
  • the CCD cameras 19 connected to each Weapon Aimpoint Card are arranged with channels 1 to 4 each covering one quarter of the main target area (fine resolution) and channel 5 covering the whole scene for that lane.
  • the cameras for channels 1 to 4 are rotated through 90 degrees.
  • the CCD cameras 19 produce an interlaced video signal with an odd and an even field. To achieve the required resolution the card uses both fields to calculate the spot centre location.
  • the microcontroller 124 is interrupted at the start of a video field. During the visible part of the field the microcontroller 124 polls the status register in LCA 153 to determine if a spot has been detected. If it has, the W, X and Y counts for the relevant channel are read for each video line on which the spot occurs. At the end of the field the microcontroller 124 calculates the spot centre location for that field. The spot centre for the next field is calculated in the same way, and the two values are averaged to give the overall spot centre location. The spot centre is given as an X, Y co-ordinate pair within the camera that detected it and has the channel number encoded in the top 3 bits.
  • the Firing Station PC 39 needs to be able to relate aimpoint co-ordinates to co-ordinates within the projected scenario. To do this the optical filters from the cameras 19 are removed and the Weapon Aimpoint Card is set in calibrate mode. The IR projector is turned off in this mode. The PC 39 sets the video threshold to a low value and projects a small block of white pixels on a black background. The Weapon Aimpoint Card generates the X, Y co-ordinates for the pixel block in the same way as it does for the IR spot. By moving the pixel block over the screen 12 the PC 39 can build up a table of results which relate scene co-ordinates to aimpoint co-ordinates. Since the video threshold needs to be set to a low value to detect pixels, cameras 19 can generate spurious aimpoint co-ordinates due to ambient light conditions. To reduce the possibility of this the video input channels may be enabled individually using the signals 162. Serial Link Operation
  • the serial link 75 is only used in AMT mode where aimpoint co-ordinates need to be transferred between Weapon Aimpoint Cards. Serial Transfers may only be initiated by the master in lane 1. If a slave card has spot data which must be communicated to another FS it waits until it is polled by the master card before sending it. The act of being polled allows a slave card to become temporary bus master and it can send spot co-ordinates directly to the correct lane.
  • the master card in lane 1 operates in promiscuous mode, so that as soon as it detects the spot location has been sent, it sends a broadcast message to end transfers. Communications Card (Fig. 17)
  • the communications card performs the following functions: Receives ten communications inputs, one from each of up to ten communications cards, and switches these on and off in accordance with control signals from the PC 39. The switched inputs are then summed to form a composite output signal for the headset 81.
  • One communications card is present in each firing station PC 39 and in the instructor station PC 80.
  • the cards communicate between each other so that all voice and aural cue communications can be heard at the instructor station 20 and at all the firing stations .
  • the communications circuit card incorporates the following circuits :
  • the card incorporates the following straps:
  • Interrupt select straps are used to select which interrupt is sent to the PC 39 when the gun FIRE signal is received from the firing station box 37.
  • a further strap which, when made, includes the headset microphone input in the summing circuit to provide sidetone. In normal use the marksman wears ear defenders and sidetone is not required, therefore this strap is left open.
  • PC INTERFACE 201 PC INTERFACE 201
  • This circuit interfaces the card to the PC data and address busses 123 and 122.
  • An address decode PAL 204 compares the address bus with the setting of a hexadecimal switch 205 to determine whether the data bus is enabled for this card. If it is, data is read onto the data bus 123 or written from it via a transceiver 206, which is enabled by the PAL 204 with its direction set in accordance with the PC read and write signals status in the address bus 122.
  • the address decode PAL 204 determines the destination of incoming data:
  • Communications analog switches 207 are coupled to the lines of the communications bus 77 by analog buffers 208.
  • the PAL 204 enables a latch 209 to store the switch enable signals.
  • the PAL 204 enables an MDAC 210, which multiplies the summed communications signals by an amount determined by the data bus 211 to set the output volume.
  • the PAL 204 enables another PAL 212 (in the gun cue circuit 202) , which then loads gun sound data for the current gun type into a RAM 213.
  • the gun cue circuit PAL 212 is loaded with data which enables it to address the RAM 213 and generate the gun sound.
  • the gun cue circuit PAL 212 is driven by a 46 kilohertz clock 214.
  • a RAM data buffer 227 is coupled between the data transceiver 206 and the RAM 213 so that the RAM 213 can be loaded with sound data from the PC 39.
  • the hexadecimal switch 205 is normally set to 0, which maps the RAMs onto the PC address bus at address 30OH.
  • the aural cue control PAL 212 monitors the FIRE signal 215 from the firing station box 37. FIRE 215 is active when a gun 17 has been fired; the PAL 212 then addresses the RAM 213, the contents of which represent the gun sound. The RAM output is converted into an analog signal via a DAC 216.
  • Fire signal 215 is also available (via a strap 230) as an interrupt to the PC 39. This enables the PC 39 to initiate its calculation of the gunshot trajectory.
  • the headset signal 217 is received directly at the instructor station, or indirectly from the firing station box 37. It is buffered (218) (differential to single line level conversion) and fed as follows: To all the other communications circuit cards (maximum of ten others) .
  • the headset signals from all the other communications cards are received at ten communications inputs 221, and are buffered and passed to the analog switches 207.
  • the external (background) aural cues which may be from any source, are received at two CUE inputs 222, are buffered, and then passed to analog switches 207.
  • the on-card aural cue signal 223 is filtered (224) (to remove step effects which may arise because the RAM store 213 is digital) , and is then passed to one of the analog switches 207.
  • the headset and aural cue signals are then switched in accordance with the data latched from the PC data bus 123.
  • This data reflects communications selections made at the instructor station and at the firing station.
  • the switch outputs are then summed with the headset signal in the summing amplifier 220 and the composite mix is fed to the analog input of the MDAC 210.
  • the MDAC 210 attenuates the mix in accordance with the status of its digital input on bus 211, which is derived from the PC data bus 123.
  • the resultant signal is output to the headset 81 of the firing station.
  • Weapon Recoil and I/O Circuit Card (Fig. 19)
  • the weapon recoil and I/O circuit card is located in the firing station box 37. It provides the interface between the gun 17 and the PC 39, and controls the compressed air actuators which simulate the gun recoil.
  • the weapon recoil and I/O circuit card incorporates the following circuits:
  • Microcontroller 96 which monitors transducers in the gun to detect when the gun is fired. The microcontroller 96 then sends the FIRED signal 225 to the PC 39. It also controls solenoids 98,99 (via transistors) to activate/deactivate the compressed air actuators for simulation of the gun recoil. If the PC 39 sets the FIRE INHIBIT signal 226 active, the gun recoil is not activated; this simulates a gun jam malfunction. The microcontroller 96 is clocked by a 12 MHz crystal clock 97.
  • the gun status signals pass through the weapon recoil and I/O circuit card to the I/O card in slot A in the PC 39.
  • Analog signals from the gun are converted by amplifiers 92, 93, 94 to the format required by the PC 39.
  • a typical weapon identification signals decode is as follows:
  • +5V power rails drive the microcontroller transistors, amplifiers, 92, 93, 94, and the analog transducers in the gun 17.
  • a +24V power rail drives the solenoids 98, 99.
  • the preferred means for generating a pulse of radiation from a simulated weapon is a combination of an IR LED and a telephoto system.
  • the LED is preferably a Honeywell sweet spot IR LED which incorporates a spherical ball lens closely coupled to the LED itself to provide effectively a small source.
  • the focal length of the telephoto system should be as large as possible to collimate the IR radiation.
  • the output lens can be a simple biconvex lens.
  • the output lens should be an achromatic doublet to reduce spherical aberration.
  • the focal length of the telephoto system may be for example 150 millimetres .
  • the concave mirror 15 may be referred to as a collimating mirror since it is intended ideally to provide an image of a target effectively at infinity. However, in practice the target image is formed at a finite distance.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • General Engineering & Computer Science (AREA)
  • Closed-Circuit Television Systems (AREA)

Abstract

Dans un simulateur de tir aux armes légères, un pistolet (17) émet un faisceau à impulsions de lumière infrarouge lorsqu'un tireur de précision utilisant ce pistolet (17) à un poste de tir (37) fait feu avec le pistolet (17) sur une cible dans une image projetée par une boîte à lumière (31) et un dispositif à miroir (34) et lentille (33) sur un écran (12) de diffusion. Un miroir Mylar concave (15) réfléchit l'image de l'écran et est observé par le tireur de précision. L'impulsion infrarouge est réfléchie par le miroir concave (15) vers l'écran (12). Un ensemble (19) de caméras visualise directement sur l'écran (12) et au moins une caméra est utilisée pour détecter la position du point d'incidence de l'impulsion infrarouge sur l'image de l'écran. Un ordinateur individuel (PC) (39) installé au poste de tir (37) calcule la position du point d'incidence dans l'image de l'écran.
PCT/GB1994/000899 1993-04-27 1994-04-27 Point de detection d'incidence Ceased WO1994025816A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU65755/94A AU6575594A (en) 1993-04-27 1994-04-27 Point of incidence detection

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB939308663A GB9308663D0 (en) 1993-04-27 1993-04-27 Point of incidence detection
GB9308663.5 1993-04-27

Publications (1)

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WO1994025816A1 true WO1994025816A1 (fr) 1994-11-10

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AU (1) AU6575594A (fr)
GB (1) GB9308663D0 (fr)
IL (1) IL109418A0 (fr)
WO (1) WO1994025816A1 (fr)
ZA (1) ZA942940B (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999014549A1 (fr) * 1997-09-16 1999-03-25 Thomson Training & Simulation Limited Simulateur
US6012980A (en) * 1995-12-01 2000-01-11 Kabushiki Kaisha Sega Enterprises Coordinates detecting device, method for same and game device
GB2354580A (en) * 1999-08-26 2001-03-28 Namco Ltd Determining the position of a spotlight
WO2007011418A2 (fr) 2004-11-24 2007-01-25 Dynamic Animation Systems, Inc. Environnement de formation dirigee par un instructeur et interfaces associees
WO2014185764A1 (fr) * 2013-05-17 2014-11-20 4°Bureau De L'etat-Major General Des Forces Armees Royales Simulateur de tir en salle pour armes légères et lance-roquettes antichars
EP2884221A1 (fr) * 2013-12-13 2015-06-17 Thales Deutschland GmbH Procédé et simulateur d'armes destiné à l'entraînement à l'utilisation et à l'usage d'armes à feu, unité de commande centrale d'un simulateur d'armes et programme informatique destiné à la réalisation du procédé

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2014708A (en) * 1978-02-20 1979-08-30 Singer Co Uk Ltd A System for Generating an Electrical Signal from a Composite Optical Display
EP0146466A2 (fr) * 1983-12-15 1985-06-26 GIRAVIONS DORAND, Société dite: Dispositif d'entraînement au tir en salle
GB2161251A (en) * 1984-07-07 1986-01-08 Ferranti Plc Weapon training apparatus
US4948371A (en) * 1989-04-25 1990-08-14 The United States Of America As Represented By The United States Department Of Energy System for training and evaluation of security personnel in use of firearms
JPH03134499A (ja) * 1989-10-17 1991-06-07 Japan Radio Co Ltd 照準位置検出方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2014708A (en) * 1978-02-20 1979-08-30 Singer Co Uk Ltd A System for Generating an Electrical Signal from a Composite Optical Display
EP0146466A2 (fr) * 1983-12-15 1985-06-26 GIRAVIONS DORAND, Société dite: Dispositif d'entraînement au tir en salle
GB2161251A (en) * 1984-07-07 1986-01-08 Ferranti Plc Weapon training apparatus
US4948371A (en) * 1989-04-25 1990-08-14 The United States Of America As Represented By The United States Department Of Energy System for training and evaluation of security personnel in use of firearms
JPH03134499A (ja) * 1989-10-17 1991-06-07 Japan Radio Co Ltd 照準位置検出方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 15, no. 346 (M - 1153) 3 September 1991 (1991-09-03) *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6012980A (en) * 1995-12-01 2000-01-11 Kabushiki Kaisha Sega Enterprises Coordinates detecting device, method for same and game device
WO1999014549A1 (fr) * 1997-09-16 1999-03-25 Thomson Training & Simulation Limited Simulateur
GB2354580A (en) * 1999-08-26 2001-03-28 Namco Ltd Determining the position of a spotlight
US6663391B1 (en) 1999-08-26 2003-12-16 Namco Ltd. Spotlighted position detection system and simulator
GB2354580B (en) * 1999-08-26 2004-04-07 Namco Ltd Spotlighted position detection system and simulator
WO2007011418A2 (fr) 2004-11-24 2007-01-25 Dynamic Animation Systems, Inc. Environnement de formation dirigee par un instructeur et interfaces associees
EP1825209A4 (fr) * 2004-11-24 2011-11-09 Dynamic Animation Systems Inc Environnement de formation dirigee par un instructeur et interfaces associees
WO2014185764A1 (fr) * 2013-05-17 2014-11-20 4°Bureau De L'etat-Major General Des Forces Armees Royales Simulateur de tir en salle pour armes légères et lance-roquettes antichars
EP2884221A1 (fr) * 2013-12-13 2015-06-17 Thales Deutschland GmbH Procédé et simulateur d'armes destiné à l'entraînement à l'utilisation et à l'usage d'armes à feu, unité de commande centrale d'un simulateur d'armes et programme informatique destiné à la réalisation du procédé

Also Published As

Publication number Publication date
GB9308663D0 (en) 1993-06-16
AU6575594A (en) 1994-11-21
IL109418A0 (en) 1996-12-05
ZA942940B (en) 1995-01-05

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