FR2699658A1 - Aim control for light weapon with target over large distance - Google Patents

Abstract

The control involves using a photosensitive array (16) receiving rays from part (14) of the optical system (12). A circuit processes the array signals and provides signals for a memory, an electroluminescent display screen (22) and the automatic firing system. The aim axis is stabilised by a gyroscope or by a cardan suspension of the optical equipment. Processing circuits display a graticule on the screen with optimum contrast. A proximity senser comprising a moving part in the optical equipment and a fixed part in the weapon detects coincidence of aim and firing axis XX1, within a predetermined tolerance.

Description

STABILIZED SIGHT WEAPON
The invention relates to the field of aiming devices for light weapons, in particular aiming devices for long-range precision shooting.

 The aiming devices for light weapons include a telescope allowing the magnification of the target. This telescope has a reticle allowing to verify that the target is in the line of sight of the weapon. We know that for long range shooting, the optical axis of sight is offset from the axis of the barrel of the weapon by a so-called rising angle or more simply by an increase which increases with distance of the target. This aspect of aiming will not be discussed for the description of the present invention and when it is spoken of aiming axis and alignment of the target with the reticle it will be a question of aiming and alignment axis. increase included.

 The problem solved by the present invention is that of the stability of the weapon. We know that for long-range shooting the weapon must be very stable, because a pointing error of 1/1000 of radian for example, or 0.06, results at 200 m by an error of 20 cm sufficient to make miss the target. We also know that despite training and precautions to have a stable position, the hands are subject to tremors making the aiming axis and the weapon's shooting axis unstable. In order to limit this instability, it is generally provided to provide the shooter with a fulcrum of the weapon in the form of a bipod or support. In this way the support of the weapon is ensured by the support, the shooter does nothing but orient the weapon and can be satisfied with a contact of lesser pressure which limits the effect of the tremors.

This known solution has the known drawbacks of limiting the speed of taking part of the target and of requiring a fulcrum which the circumstances of combat do not always provide. In addition, efficiency assumes that the target is fixed or weakly mobile.

 The object of the invention is to provide a sighting system which does not require any support and which allows good alignment of the target and the reticle despite the tremors of the shooter. It is also to start firing when the axis of the weapon is aligned with the target.

 To achieve the above defined goal, it is provided according to the invention to stabilize the aiming axis only, and no longer the entire weapon comprising the aiming axis, to measure the difference between the aiming axis stabilized and the axis of the weapon and to fire only when this difference is less than a predetermined value.

 The term measure should be understood in its broadest sense.

In particular according to the present invention, we are not interested in the value of the angle of deviation between the sighting axis and the shooting axis itself, we simply seek to verify that the angle between the two axes is less than a predetermined value.

 This can be obtained by comparison of value at a threshold but also by detection of coincidence by an all or nothing system.

 The above method assumes that the target or the firing axis have been previously designated. The idea underlying the invention is based on the fact that, on the one hand, it is easier to stabilize a part of the weapon simply than the whole weapon. It is based on the other hand on the idea that there is a great probability that the real axis of shooting of the weapon, will coincide during its erratic movements due to the tremors of the shooter with the axis of sight stabilized. The coincidence between the firing axis and the aiming axis is considered to be established if the angle between the firing axis and the aiming axis is less than a predetermined or pre-set threshold which can be a function of the distance from the target.

 Thus the invention relates to an individual weapon having a barrel centered on a firing axis XX 'and optronic sighting means defining a sighting axis YY' of the weapon, a means for controlling the firing of ammunition fired by the weapon actuable by a carrier of the weapon, weapon characterized in that it comprises means for stabilizing the axis YY 'of aiming, means for detecting angular coincidence between the aiming axis YY 'and the firing axis XX' these means emitting a firing signal when there is coincidence between the two axes and in that the firing control includes a firing authorization means actuable by the bearer of the weapon and an automatic firing circuit triggering the firing of the ammunition when the authorization means has been actuated and that the coincidence detection means emit the firing signal.

 Thus, according to the invention, the trigger tail which is the usual device for firing the ammunition carried by the weapon is replaced or supplemented by a device which only authorizes the firing. This device can be constituted by a mechanical or electrical member controlled by a shooter's finger and placed at the usual location of the trigger tail when the member replaces the trigger tail or close when the member replaces the trigger tail. .

 This separation between fire authorization and effective fire control improves accuracy.

 Naturally the shooter waits to activate the trigger tail that the target is in alignment with the line of sight, which in a weapon according to the prior art permanently corresponds to the axis of fire.

However, the simple pressure of the finger on the trigger tail and the time necessary for this movement are enough to modify the axis of fire.

The dissociation according to the invention makes it possible to increase the speed of firing after authorization when the axis YY 'is aligned with the axis XX'.

 The means of stabilization of the line of sight will depend on the nature of the optical means used. These means allow the shooter to materialize the line of sight by means of a collimated reticle, the position of which in the field of optical means constitutes the designation of the target. Stabilization of the aiming makes it possible to stabilize the position of the reticle on the target despite the tremors of the shooter.

 Various systems for stabilizing an image are known in the art. They can be classified into two categories. closed loop systems and open loop systems. In closed-loop systems, two categories can still be distinguished, depending on the nature of the motion detectors. Detection can be ensured using a matrix of CCD sensors receiving an image obtained by optical means and a computer determining a motion vector. It can also be provided by gyroscopic sensors. In both cases, the detected movement is applied to means for correcting the image capture optics. In open-loop systems, stabilization is obtained, for example, by suspending optical means from CARDAN. In this case, proximity sensors detect the coincidence between the firing axis and the aiming axis.

 The detection of the coincidence between these two axes that they are ensured by means of a proximity sensor or by the value of the correction signal in closed loop systems is used to trigger the creation of a firing signal which itself directly or indirectly will create the firing.

 With a suitable munition that can be fired electrically, for example by means of an exploded wire detonator, the firing signal will be used directly. This solution is excellent because of the speed of reaction which it allows, much less than a millisecond, but has the disadvantage of a high cost due to the price of primers and the need to carry out ammunition in small quantities.

 With ordinary ammunition, the firing signal can be used to move a plunger core causing a striker to strike the ammunition. or releasing a striker usually pushed by a spring.

In order to facilitate the understanding of the invention without however entering into detailed descriptions which are unnecessary since already known to those skilled in the art, it will be cited below for publication or production references describing loop image stabilization systems open or closed;
Stabilization methods using a CCD matrix, allowing motion detection by image processing are described for example in the "SMPTE Journal February 1992, pages 66 to 75" in an article entitled "Electronic Image Stabilization system for
Video Cameras and VCR, "whose authors are Kenya UOMORI,
Atsushi MORIMURA and Hirofumi ISHII or in an article by the IEEE
Transaction on Consumer Electronics "vol 36 nO 3 of August 1990 pages 510-519 entitled" Automatic Image Stabilizating System by Full Digital signal Processing "whose authors are the three previously mentioned authors and Takashi SAKAGUCHI and Yoshinori KITAMURA or in another article located in the same publication following this last page 520-524 and entitled "Electronic Image Stabilizer For Video
Camera Use ".

 Such methods are used in high magnification handheld camcorders, for example PANASONIC NV 7 or S6 VHS C (registered trademark).

A method of stabilization using a gyroscopic detector allowing the detection of the angular difference between an axis defining the support structure of the optics and the optical axis is described in an article by the IEEE Transaction on Consumer electronics vol 35 no. 4 November 1989 pages 749-757 and used on SONY CCD-TR 805 E handheld camcorders (registered trademark). The sensor used can for example be the GYROCHIP TM 5 (registered trademark) produced by
SYSTRON DONNER - Inertial Division at DOVER, KENT.

In open-loop stabilization systems, the 20x60 s Binoculars from the Karl ZEISS firm can be cited as an example in which the optical means are suspended from the
Cardan.

 The embodiments in which the optical means consist of a telephoto lens forming an image on a matrix of sensors, each sensor delivering a signal as a function of the illumination received, have the advantage of authorizing night shooting when the matrix of sensors is made up of sensors sensitive to infrared rays.

 The angular deviation detection device between the position of the aiming axis and the actual position of the shooting axis can be produced by any known position detection means. Note however that the difference in itself is not important to know since according to the invention there is no means to bring the shooting axis into coincidence with the aiming axis. According to the invention, we only wait until the erratic movements due to the tremors cause the two axes to coincide. Also in the case where stabilization is obtained by mechanical stabilization of the optical means, the detection of the coincidence between the two axes may for example be carried out by a proximity sensor.

Examples of embodiments with image stabilization in open or closed loop and variants of the invention will now be described with reference to the accompanying drawings in which:
- Figure 1 shows a weapon produced according to the invention with electronic stabilization of the line of sight;
FIG. 2 represents a functional diagram of the invention for an image stabilized by electronic means;
- Figure 3 is intended to illustrate the choice of color of the reticle to obtain a good contrast with the target;
- Figure 4 shows a weapon produced according to the invention with mechanical stabilization of the line of sight;
- Figure 5, is an example of proximity sensor adapted to the weapon according to Figure 4;
- Figure 6 illustrates the processing mode of the sensor according to Figure 5 ;;
- Figure 7 shows another functional diagram of the invention with development of a real reticle.

 Figure 1 shows a rifle 10 equipped according to the invention. This rifle 10 intended for precision shooting comprises a barrel 11 of axis XX ', a stock 17 comprising a layer plate 20, a trigger guard 19, a telescopic sight 12 comprising an optical axis YY', a objective 14 and an eyepiece 13. All these elements are arranged in a conventional manner. The telescope 12 comprises between the objective and the eyepiece a matrix of sensors 16 on which is formed by a first prism 15 The electronic image of the landscape seen by the objective. This image processed by an electronic image processing circuit 21 is used to form a stabilized image on a miniature electroluminescent screen 22.

 This screen has as many pixels and arranged in the same way as the array of detectors.

 In the exemplary embodiment, it is a matrix and a screen of 1024 × 1024 pixels. This image is returned by means of a second prism 23 to the eyepiece 13 of the telescope 12. The center of the matrix corresponds to the position of the optical axis of the telescope. This center is represented by a crosshair 30 in the form of a cross along two perpendicular axes shown in FIG. 3.

 The pixels located on these two axes appear by special treatment in white or black so as to obtain the best contrast between the image observed and the reticle. For this, the processing circuits 21 calculate a weighted average brightness in an area corresponding to the pixels forming a cross-shaped surface surrounding the reticle 30. The average is said to be weighted because as explained below with reference to FIG. 3, it is applied a heavier weight to the pixels located at a smaller distance from the reticle. Figure 3 shows a portion of the central area of the screen entering into account for determining the white or black color of the reticle. FIG. 3 represents a reticle 30 formed by the crossing of a vertical line of pixels 31 and a horizontal line of pixels 32.

The weighting of the gray levels of the pixels having a symmetry with respect to each of the lines 31 and 32, it will only be spoken below of the upper right corner. The average of the gray level of the cross-shaped area surrounding the reticle 30 is said to be weighted in the sense that greater weight is given to the gray levels of the pixels of the vertical 33 and horizontal 34 lines which are the most closer to the pixels forming the reticle, than to the gray levels of the vertical 35, horizontal 36 lines which are a little further away.

 The weight of each vertical or horizontal line taken into account thus decreases with its distance from the vertical 31 and horizontal 32 lines, lines of pixels defining the reticle.

 The contrast enhancement process can be transposed directly to a screen that would be in color. It is necessary to have introduced into the software a matrix of contrasting colors.

 The method for processing the image of the sensor matrix 16 using processing circuits incorporated in the module 21 makes it possible, in a manner known as explained above, to define a motion vector of the image with respect to an image of reference. When the modulus of this vector is less than a determined threshold, it is considered that the firing axis is aligned with the line of sight. In this case, if a key 18, located under the trigger guard has been pressed, the shot is triggered automatically.

 The automatic percussion device is not shown.

The circuit 21 generates, when the two axes are close enough, a signal which is used to produce a current in a coil. This current activates the withdrawal of a nucleus. This withdrawal releases a striker conventionally pushed by a spring.

 An embodiment of the circuit 21 and its operating mode will be explained below with reference to FIG. 2.

 This circuit includes a module 25 for analyzing the image from the sensors 16. This analysis is carried out by comparison with a previous image, the data of which is stored in a field memory 24. The analysis consists in determining a motion vector between a previous image and the current image and in the possible determination of a voluntary motion vector.

 If the value of the module of the motion vector is less than a predetermined threshold and if there is no detection of voluntary movement, the circuit 21 generates a firing signal.

 This signal is transmitted to a circuit 26, for producing a firing trigger current. This current can only be produced when a status bit produced from the pusher 18 is at the value 1, representing the authorization of the firing.

 The module 25 includes a sub-module 27 for optimizing the contrast of the reticle, the role of which has been defined above.

 Another embodiment will now be described with reference to Figures 4 to 6. In these figures the elements having the same function as those of Figures 1 and 2 have the same numbers.

 This exemplary embodiment (FIG. 4) relates to a rifle 10 equipped with a riflescope 12 with a stabilized optical axis. As has been seen previously, in this type of telescope optical elements are gyrostabilized or suspended so as to obtain a stable image despite the tremors of the wearer. In this case, provision is made according to the invention to provide at least one of the stabilized optical elements with a part 41, constituting the mobile part of a proximity sensor 40. The fixed part 42 of this same sensor is fixed to a fixed part of the telescope. This type of sensor is well known in the art and there are many varieties.

This type of sensor is characterized by the absence of mechanical connection between the measuring device and the moving object; it is through a field that an interaction is established between them, a function of their relative position:
- magnetic induction field for reluctance variation, Hall effect or magneto resistance sensors;
- electromagnetic field for current sensors
Foucault;
- electrostatic field for capacitive sensors.

 In the embodiment, a capacitive sensor has been chosen.

 For this and as shown in Figure 5 in a longitudinal section of a trunk of the telescope 12, metal deposits were made on the one hand on the peripheral ring 44 of a stabilized optical element 45 and on the other hand, in two crowns 46, 47 located in front of and behind the optical element 45 on a fixed part 50 of the telescope.

 When the axis of the optical element 45 is aligned with the axis of the crowns 46 and 47, the value of the capacity formed by the armatures 44 and 46, 47 is almost zero.

 However, the value of this capacity increases with the misalignment.

 The electrical circuits 53 (FIG. 4) measure this capacity and trigger a firing signal, when the measurement indicates that the capacity is below a certain threshold.

 A diagram of the circuit 53 is shown in FIG. 6. The capacity 49 formed by the armatures 44 and 46, 47 is measured in a circuit 48.

 This circuit emits a signal when the capacity 49 is less than a predetermined threshold. This signal is used as in the previous embodiment by a circuit 26 to develop the firing current, if an authorization from the pusher 18 is given.

 An operating mode with production of a movable reticle corresponding to the real line of sight on the stabilized image will now be described with reference to FIG. 7.

 This figure represents an optical telescopic sight 712 possibly equipped with means for forming an electronic image. This telescope is equipped with image stabilization means 725 producing a stabilized image 740 comprising at its center a fixed reticle 730 materializing the axis XX 'of shooting. A device 760 detects the difference between the stabilized image 740 and the real image. This detection makes it possible to develop in a module 731 a reticle 729 corresponding to the actual position of the shooting axis in the stabilized image and thus to inform the shooter of the aiming deviation. The coincidence between the two reticles is determined in a 750 module.

 A signal produced by the module 750 makes it possible to actuate an electrical firing command if the push button 18 has been pressed.

Claims (9)

 1. Individual weapon (10) having a barrel (11) centered on a firing axis XX 'and optronic sighting means (12, 712) defining a sighting axis W' of the weapon (10), a means of control of the firing of a munition fired by the weapon actuable by a carrier of the weapon, weapon characterized in that it comprises means (15, 16 - 22, 23 13, 14, 725) for stabilization of the sighting axis YY ', means for detecting angular coincidence (16, 24, 25 - 48, 49) between the sighting axis YY' and the firing axis XX ', these means emitting a setting signal when there is coincidence between the two axes and in that the firing control comprises a firing authorization means (18) actuable by the carrier of the weapon and a firing circuit automatic fire (26) triggering the firing of the ammunition when the authorization means (18) has been actuated and the coincidence detection means emit the firing signal.  2. Weapon (10) according to claim 1, characterized in that the means of stabilization of the line of sight consist of a matrix (16) of photosensitive sensors receiving the radiation received by at least part (14) of the means optronics (12), means for storing (24) at least part of an image formed on the matrix (16) of photosensitive sensors, and processing circuits (25, 725) receiving signals from the matrix ( 16) of sensors, storage means (24), the processing circuits (25) sending signals to the storage circuits (24), to a display screen (22) and to the automatic firing (26) .  3. Weapon (10) according to claim 2, characterized in that the screen is an electroluminescent screen (22) viewable by the carrier of the weapon by means of at least part (13) of the optronic means.  4. Weapon (10) according to claim 2, characterized in that the processing circuits (25) form a reticle (30) on the screen (22).  5. Weapon (10) according to claim 4, characterized in that the processing circuits (25, 725) comprise a module (27) for optimizing the contrast of the reticle (30).  6. Weapon (10) according to claim 1, characterized in that the means of stabilization of the line of sight YY 'are constituted by gyroscopic means of stabilization of the optical means.  7. Weapon (10) according to claim 1, characterized in that the means of stabilization of the line of sight YY 'are constituted by means of suspension from the gimbal of the optical means.  8. Weapon (10) according to one of claims 6 or 7, characterized in that the coincidence detection means consist of a proximity sensor (40) comprising a movable part (44) linked to a part of the optical means and a fixed part (46, 47) linked to a part (50) linked to the structure of the weapon.  9. Weapon (10) according to claim 1, characterized in that it comprises circuits (725, 760, 731) allowing the visualization of a reticle (729) corresponding to the real axis of shooting.