Abstract:
The present invention describes a marksmanship simulator including a weapon capable of firing a laser, a screen for projecting images thereon and for receiving a laser strike from the weapon, a first hit detection means for registering a laser strike on the screen, a first projector for projecting a background image and a separate target image on the screen. The target image is finer than the visual acuity of the marksman, when looking through a targeting means thus providing a more realistic image for the marksman.

Description:
FIELD OF THE INVENTION  
       [0001]     The current invention relates to a marksmanship training device for assisting in firearms training.  
       DESCRIPTION OF THE PRIOR ART  
       [0002]     There are numerous types of training devices for teaching marksmanship skills. These include: live-raining-ranges with traditional paper or cardboard targets and live ammunition; automatic scoring systems using acoustic-location for detecting the path of the bullet as it flies past the target; simulated ammunition that has similar ballistic characteristics to actual ammunition.  
         [0003]     More recently live training ranges have also been developed where ammunition is replaced with lasers on rifles and handguns to simulate a shot fired by a user. Targets (either live or static) require the attachment of light detectors to detect hits. Such systems typically suffer from lack of sophistication in simulation of trajectories and ballistics. In such systems there is no simulation of fall of the shot, but rather some assumptions are made that if the laser beam strikes a photo detector that a hit has occurred.  
         [0004]     Such ranges are useful for training of teamwork and procedures, but trainees need additional training for the actual fine-motor skill that includes all the ballistics that is present with real guns and ammunition. Indeed, some studies have shown that the use of current training simulators has resulted in negligible transfer of skills to live firing ranges.  
         [0005]     As costs of computer technology continue to decline, there has been increase in activity in the development of indoor rifle and gun simulators. A laser attached to a simulated rifle can illuminate a spot on the screen and this illumination can be detected by a camera. When the trigger is pulled the computer can use the location of the detected aim-point on the screen to and calculate the ballistics of the ammunition and simulate an appropriate hit on the simulated target.  
         [0006]     On the surface, such systems appear to enable relatively realistic simulations for the training of marksmanship. The potential advantage of such systems is that they use no ammunition, are not dependant on weather conditions and can be used at any time of the day or night. Therefore they are quite attractive propositions for low-cost training, or even training in places impossible in the past, for example marksmanship training on submarines where access to live-ranges is not practical.  
         [0007]     Existing typical indoor small-arms trainers include a simulated rifle, hand gun, artillery or other weapon that normally ejects a projectile; a sighting system that may be telescopic, but could be simpler (such as the iron sights on the end of a rifle) or more sophisticated (such as a head up display for tracking multiple targets).  
         [0008]     There is also typically a laser embedded in some part of the rifle, which can either generate a continuous beam for continuous tracking, or controlled by a trigger on the simulated weapon. A projector is required to generate a computer controlled image on the screen and a camera that views the whole screen. Laser strikes on the screen generate a bright signature over the projected image and this is detected by the camera. In this manner a target a can be projected anywhere on the screen, and the target may be a bullseye or other type target used for marksmanship training, or could be a moving target.  
         [0009]     Computers are used to then control the weapons and effects simulation of the overall system.  
         [0010]     Variations to such systems include where the projected image and camera areas are combined using combining mirror and then projected onto sub-parts of the whole screen (U.S. Pat. No. 6,942,486 B2, which is incorporated herein by reference only). This allows simpler detection of a hit on a target, since the projector is projecting only the target and the light sensitive hit detector are both covering the same area. A hit is registered when the laser light reaches the light-sensitive detector.  
         [0011]     Where a non-visible overlay image is projected onto the screen in addition to the visible image (U.S. Pat. No. 5,690,492, which is incorporated herein by reference only). This variation requires a light-sensitive detector to be mounted on the weapon (such a light-sensitive detector might be part of the actual weapon) to become the hit detector, thus eliminating the requirement for the simulation computer to determine the hit detection.  
         [0012]     Electronic or electromechanical devices to emulate some aspects of ballistics. For example U.S. Pat. No. 5,194,006, which is incorporated herein by reference only, introduces an electronic counter to count a predetermined number of scan lines before registering a shot. The use of a counter introduces a delay that a marksman would expect for the time taken for a bullet to reach the target. This is important if a marksman is practising hitting a fast moving projectile, such as a skeet.  
         [0013]     Additional sensors in the simulated weapon such as pressure sensors in the rifle butt and trigger, as well as and gravity sensors built into the rifle to detect orientation are used in conjunction with the laser hit detection system in an attempt to improve training effectiveness.  
         [0014]     Accordingly, we have found that the current state of the art indoor-simulation techniques do not provide an environment that is conducive for the learning of marksmanship skills, and there are several factors leading to this situation:  
         [0015]     Hit Detection: Current laser detection techniques assume that the laser landing on the screen is a point source, whereas it is actually has a sizable spread. When aiming at a simulated distant target the size of the spread of the laser can be significant in size compared to the size of the target. In such conditions the assumption that the laser spot is a point breaks down, and the feedback generated by the training system becomes meaningless.  
         [0016]     Spread of Shots: Similarly, for a simulated distant target, the target area can be very small and the resolution of the hit detector cameras may not be able to discriminate the spread of shots fired at the target.  
         [0017]     Image Resolution: For a simulated distant target, the visual representation of the target may only fall on a few pixels, and so the representation of the target may be coarse to look at.  
       OBJECT OF THE INVENTION  
       [0018]     It is an object of the present invention to provide a marksmanship simulator that provides for greater training and translation of skills to live firing.  
         [0019]     It is a further object of the present invention to overcome, or at least substantially ameliorate, the disadvantages and shortcomings of the prior art.  
         [0020]     Other objects and advantages of the present invention will become apparent from the following description, taking in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.  
       SUMMARY OF THE INVENTION  
       [0021]     According to the present invention, although this should not be seen as limiting the invention in any way, there is provided a marksmanship simulator including a weapon capable of firing a laser, a screen for projecting images thereon and for receiving a laser strike from the weapon, a first hit detection means for registering a laser strike on the screen, a first projector for projecting a background image and a separate target image on the screen.  
         [0022]     In preference, the target image is finer than the visual acuity of the marksman, when looking through a targeting means.  
         [0023]     In preference, the target image is of greater resolution than the background image.  
         [0024]     In preference, the separate target image is provided by a second projector.  
         [0025]     In preference, the separate target image overlays the background image.  
         [0026]     In preference, there is a second hit detection means aimed at the screen.  
         [0027]     In preference, the second hit detection means at least substantially overlaps the target image displayed by the second projector.  
         [0028]     In preference, the resolution of the second hit detection means is greater than that of the first hit detection means.  
         [0029]     In preference, the second hit detection means is adapted to detect the centre of a laser footprint of the laser to a precision that is at least better than the accuracy required of the marksman.  
         [0030]     In preference, the hit detection means is a camera capable of viewing laser strikes on the screen.  
         [0031]     In preference, the separate target image is positioned In front of the screen.  
         [0032]     In preference, the separate target image is constructed from a material capable of reflecting laser light.  
         [0033]     In preference, the separate target image is of a substantially higher resolution to that of the back ground image.  
         [0034]     In preference, the second projector projecting the separate target image and the second hit detection camera is movable relative to the screen.  
         [0035]     In preference, the second projector and the second hit detection camera are attached to a platform that is computer controlled so as to allow movement of the platform relative to the screen.  
         [0036]     In preference, the computer calculates the real time screen location of the separate target image provided by the second projector and blanks out an area of the background provided by the first projector, where the target image is overlaid. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0037]     By way of example, an employment of the invention is described more fully the renown for with reference to the accompanying drawings, in which:  
         [0038]      FIG. 1  is an example of the prior art training system,  
         [0039]      FIG. 2  is a diagrammatic representation of the hit detection when a laser pulse footprint is relatively large compared to the target screen resolution,  
         [0040]      FIG. 3  is a diagrammatic representation of the spread of shots registered over a relatively large hit detection pixel,  
         [0041]      FIG. 4  shows the comparison between eye resolution target and progressively worse image resolution due to simulation image generation artefacts.  
         [0042]      FIG. 5 a  preferred embodiment of the current invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0043]     As indicated previously, current indoor small-arms trainers known in the prior art, as shown in  FIG. 1 , have the following typical components, which include a simulated weapon  10 , a sighting system  12 , a laser  13  attached or embedded in some part of the weapon, either generating a continuous beam for continuous tracking, or controlled by a trigger on the simulated weapon  10 .  
         [0044]     A projector  14  generates a computer-controlled image on the screen  16  and a hit detection camera  15  that views the whole screen  16 . Laser strikes  18  from the weapon  10  on the screen  16  are then detected by the hit detection camera  15 .  
         [0045]     A target image  20  can be projected anywhere on the screen  16  by the camera  14 , this may be a bullseye or other type target used for marksmanship training, or could be a moving target, along with any background image  22 . The target image  20  is then viewed through the sight  21  of the weapon  10  to give a field of view  19 .  
         [0046]     A bright signature area  18  generated by the laser  13  on the weapon  10  then hits the screen  16  This is then detected by the hit detection camera  15 , which scans the entire screen  16 . Data from the hit detection camera  15  is then transferred to the computer  25  for processing and display either on a separate monitor or on the screen  16  as required. The data can be stored for later retrieval as required.  
         [0047]     The computer  25  also controls the image projector  14  as well as accepting feedback from any sensors associated with the simulated weapon  10 .  
         [0048]     Such prior art simulation devices rely on a single hit detection camera to detect the laser-beam strike anywhere on the screen. The position of the laser strike is then correlated to the position of the target. This process is independent of the projected image. The laser detection system sees the screen as a set of distinct blocks, each block typically referred to as a ‘pixel’  42 .  
         [0049]     One problem observed with hit detection systems is that the lightweight solid-state lasers used in simulators do not have light rays that are perfectly parallel. This means that the footprint  40  of the laser beam hitting the target is relatively greater in size compared to the pixels  42  and not a perfect point,(See  FIG. 2 ).  
         [0050]     This creates a problem in that the computer system must then have some method for choosing a single pixel for returning to the host computer for the purpose of providing an aiming point of the simulated weapon. Current state-of-the-art systems return the first pixel  10  detected. Hence, we have found that if two points are illuminates artificially and the two points are separated by many pixels, then systems registers a hit on the pixel that the scanning hit detection camera first detects, which in the case of a left-to-right scanning system would be the left-most pixel  44 .  
         [0051]     A related problem with prior art systems is that of detecting the spread of shots on a target area that subtends a small angle to the eye of the marksman. The limiting factor in this case is the resolution of the hit detector camera.  
         [0052]     Even if the laser spot size could be made very small, if the hit detection camera has large detection pixels it would be unable to detect the spread of shots. For example,  FIG. 3  shows the case of a small target  50  (a common situation for shooting at simulated targets at even short distances for typical marksmanship tasks) and the shots  52  are spread across the target area  50 .  
         [0053]     In this example, the target  50  only spans two by two pixels on the hit detection camera system. The centre of the laser footprints for a number of shots  52  represent the point at which the simulated weapon was aimed It is possible that, all these shots  52  fall on a single pixel of the hit detection camera system. As such the computer would register all these shots as having landed on the same pixel.  
         [0054]     Studies of a typical simulator employing this approach to hit detection have found that simulators may use other sensors (such as an electronic spirit levels, pressure sensors on various parts of the simulated weapon) to simulate a spread of shots. However, these approaches do not actually detect the actual point at which the marksman was aiming at the point in time at which the trigger was pulled. Hence the actual fine-motor skill in firing the simulator is significantly different to that of actually aiming the simulated weapon.  
         [0055]     When simulating a typical rifle-range target at a distance of 100 metres from the marksman, the limitation of the camera resolution typically presents an area of 50 mm square on a target projected on the screen. That is, the camera limitation does not enable the discrimination of shots falling within 50 mm of each other. The laser beam emitted from the modified weapon also has a foot-print comparable or greater in size to the individual “blocks” or “pixels” of the hit detection camera.  
         [0056]     Analyses indicate that the laser footprint may encompass anywhere between four to nine pixels (that is the laser strike footprint has a diameter of approximately two or three pixels camera pixels). These two effects, the low camera resolution, combined with, the large laser footprints, result in significant errors regarding the output of the simulated fall of shot that is the errors between shots is comparable to the grouping required for the qualification of a marksman, hence the marksman cannot tell if the grouping size occurs because of his skill or the errors in the simulator.  
         [0057]     For example, a typical ‘qualification shoot’ can require marksmen to group a series of shots within 150 mm diameter of a target at 100 metres (in live ranges at distances of 100 metres, expert marksmen can typically achieve group sizes in live ranges less than 80 mm in diameter). However, the errors in the simulators can be anywhere from 50 mm to 100 mm for a series of ten shots. It is clear that the errors in small-arms trainers are of the order that marksmen are required to train for, and hence the feedback for skill developments becomes meaningless since a group size of the order of 100 mm could be attributed solely to the simulator.  
         [0058]     Image generation equipment on current simulators provides synthetic imagery that is projected on to a screen to allow the trainee to acquire, aim and fire. The target has artefacts as a result of being a digitised projected image. One of these artefacts is finite image resolution resulting from the projector and image generation systems.  
         [0059]     At first this may appear not to be a problem since the distance from the screen to the trainee is such that the individual pixels on the screen are not resolvable by the human eye.  
         [0060]     However, when this technology is used for simulator applications, as in the case of the small arms trainers, the scenery is spread over a much larger area so as to ‘immerse’ the trainee in the synthetic environment, and then the target has fewer pixels for visual representation. With small arms trainers, the target is viewed through a telescopic sight and the small target image is magnified making the pixels clearly discernible.  
         [0061]     It has been shown that there is a significant quantifiable detrimental effect on performance when aiming at poorer resolution targets. An example of image resolution of the projected target is shown in  FIG. 4 , showing an eye limited resolution target  60  compared to progressively worse resolution,  62  and  64  respectively, due to simulation image generation artefacts.  
         [0062]     It is proposed that separate ‘high-resolution’ hit detection cameras be included in simulators.  FIG. 4  shows the preferred embodiment. Referring to  FIG. 4 , the conventional hit detection camera  15 , is now supplemented by a second hit detection camera  32 , which is aimed only at the target image  20 . Camera  32  captures only the target of interest and so the whole resolving power of the camera is focussed on a small region of the screen  16 .  
         [0063]     The physical size of the detection pixels are therefore of much smaller size than those using the conventional approach.  
         [0064]     When the trigger of the simulated weapon  10  is pulled, the camera  32 , records the picture of the whole target area  20 . Since camera  32  is tuned to the infrared wavelength of the laser  13 , the image recorded by the camera  32  will contain the laser footprint against a blank background. This image can then be signal processed so as to determine the centre of the footprint, and hence the point where the simulated weapon  10  was aimed much more accurately than is currently achieved by using camera  15  alone.  
         [0065]     An alternative solution, or one used in conjunction with the previous solution would include a focussing lens arrangement on the laser  13  to focus the near parallel rays of the laser  13  to as small a spot on the screen as possible. As a person skilled in this art would understand, there may be a need to include some means of providing an aperture to restrict the width of the laser beam and so producing a smaller spot on the screen  16 .  
         [0066]     Additionally, The hit detection camera  32 , used for imaging the laser footprint  18  also provides a high-resolution detection surface for determining the aim-point of the simulated weapon  10 . Hence, the camera  32 , can detect the centre of the laser footprint  18 ; and determining the aim-point of the simulated weapon  10  to a high degree of accuracy.  
         [0067]     To provide the fine resolution target imagery for the target image  20  the rays  36  emanating from the inset projector  31 , are focussed only on the target  20  area of interest. Since projector  14  is also projecting over the whole screen, projector  14  should preferably not illuminate the target area  20 . This can be achieved by having the computer-generated image  22  projected by projector  14 , to have a black shape substantially corresponding to the shape of the target area  20 .  
         [0068]     This will eliminate the human performance issues of not being able to clearly and effectively aim on target due to poor target definition.  
         [0069]     Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, and that various modifications may be made in details of design and construction without departing from the scope and ambit of the invention.