Abstract:
Provided is an RPG disruption system (RDS) for protecting an enclosure against RPG&#39;s, the system including a casing fixed in close proximity to a wall of the enclosure facing an anticipated RPG threat. The casing includes an anvil accommodating a propelling mechanism for propelling the disrupting element, and an activating system for activating the propelling mechanism so as to propel the disrupting element towards an approaching RPG, to thereby neutralize it.

Description:
This is a National Phase Application filed under 35 U.S.C. §371 as a national stage of PCT/IL2009/000702, filed on Jul. 15, 2009, an application claiming the benefit under 35 U.S.C. §119 of Israeli Patent Application No. 194090, filed on Sep. 15, 2008, the content of each of which is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     This invention relates to a system and method for protecting an enclosure against attack of projectiles and in particular, but not restricted, against the attack of Rocket Propelled Grenades (RPGs). 
     The term ‘enclosure’ as used herein the specification and claims denotes any form of vehicle such as land vehicles (e.g. soft vehicles, trucks, Armoured Personnel Carriers (APCs), Armoured Fighting Vehicles (AFVs), self propelled guns, etc.), maritime vessels and helicopters and different forms of structures, e.g. buildings, bunkers, warehouse, etc. 
     The term RPG is used herein in its broad definition and refers to a variety of rockets fitted with a shaped (hollow) charge shaped so as to focus the effect of the explosive energy and fitted with a sensor. 
     BACKGROUND OF THE INVENTION 
     When discussing protection of combat vehicles e.g. troop carriers, tanks and the like, one may consider using a variety of different passive or reactive armors, the latter typically comprising protective modules comprising in turn one or more plates with explosive material embedded there between, to be ignited upon impact of a projectile, resulting in imparting the one or more plates to propel in a direction so as to disrupt the kinetic energy and that of a hollow charge of the threat. 
     It is also known to increase effectiveness of protection systems by utilizing a threat detecting system for instant activating protective modules facing the upcoming threat. 
     U.S. Pat. No. 6,681,679 discloses an active protection device for a wall against attack by a projectile and comprising: at least one explosive charge able to project at least one metallic block in the direction of the projectile, wherein each block of the at least one block is in the shape of an elongated bar which has a maximal length greater than or equal to 10 times a smallest crosswise dimension, the explosive charge being positioned opposite a longitudinal surface of the bar; and a support having a bottom plate intended to be fastened to the wall and onto which the explosive charge is placed, wherein the support incorporates a longitudinal cavity delimited by two lateral checks and accommodating the explosive charge and the at least one bar. 
     One type of threat often used against light vehicles is the widely used RPG, in its various forms, which is up to date considered as one of the most successful antitank grenade ever manufactured. An RPG is usually fitted with a shaped charge comprising a cylinder of explosive with a metal-lined conical hollow, an inverted metal-liner cone which together constitute a ‘hollow space, a detonator in conjunction with the explosive, said detonator being electrically coupled to a Piezo-electric sensor at a fore end of the missile via a conductive aerodynamic cover and said liners. In some cases there are provided electric wires instead of conductive liners. 
     The arrangement is such that upon impact of the Piezo-electric crystal sensor with a target, an electric current generates and is conducted via the conductive aerodynamic cover and said liners to ignite the detonator resulting in detonation of the explosive which drives the conical liner to collapse upon its central axis. The resulting collision forms and projects a high-velocity jet of metal and gases (plasma) which is deadly and devastating. 
     Various solution have been proposed for protecting tanks, APCs and structures, ranging from reactive armor systems, through metal slat-armor in the form of a metallic cage mounted on the enclosure to be protected, ending with sand bags placed there over. 
     SUMMARY OF THE INVENTION 
     The present invention is concerned with a system and a method for neutralizing Rocket Propelled Grenades (RPGs), i.e. preventing initiation of the explosive material of the RPG before it strikes against an enclosure to be protected. 
     Disrupting, according to the present invention is in the sense of preventing electric initiation of the charge of the upcoming threat by shortcutting or detaching electric wiring associated therewith. 
     According to the present invention there is provided an RPG Disruption System (RDS) for protecting an enclosure against RPG&#39;s, the system comprising a casing fixed in close proximity to a wall of the enclosure facing an anticipated RPG threat, said casing comprising an anvil accommodating a propelling mechanism for propelling said disrupting element; and an activating system for activating said propelling mechanism so as to propel the disrupting element towards an approaching RPG, to thereby neutralize it. 
     According to the present invention the RPG is neutralized by preventing the detonator from activating the explosive. This is obtained by disrupting/preventing the electric initializing of the explosive either by breaking or truncating the Piezo-electric sensor from the RPG or by causing an electric shortcut by deforming the conductive wires or aerodynamic cover and inner part. 
     The system and a module according to the present invention may further comprise any one or more of the following features:
         The disrupting element is propelled in a plane substantially parallel to said wall. However, according to a modification of the invention, the disrupting element may be propelled non-parallel to the wall, depending on the type of mounting.   A sensor is provided for early detection of a launched RPG, for initiating one or more systems according to the present invention, facing an approaching RPG. The sensor may be a thermal detector, flare detector, blast detector, image detector, etc., whereby upon detection of an approaching RPG the system is armed and is ready to handle the threat. Otherwise, the RPG Disruption System (RDS) may be manually initiated (e.g. by a commander of a vehicle) or it may normally set to an initiated, active state.   The propelling mechanism is designed for propelling the disrupting element by applying a bursting force of great magnitude between the anvil and the disrupting element, e.g. an explosive charge generating thrust, a magnetic force, or different forms of springs such as a preloaded mechanical spring, discharge of compressed gas, etc.   A detection system is provided, defining an imaginary plane covered by the disrupting element, generating an activating signal to instantaneously propel the disrupting element. Such a detection system can be an optic sensor, magnetic sensor, acoustic sensor and the like.   The detection mechanism may be in the form of a mechanical barrier defining an imaginary plane, e.g. a fine mesh, web or grid, whereupon tensioning, pressure or piercing same generates the activating signal. Such a detection mechanism may be a sheet emitting an electric pulse upon change in tension or tear thereof.   A controller/microprocessor is provided for generating a control signal to activate the propelling mechanism at a calculated timing such that the propelled disrupting element is likely to engage the approaching RPG and neutralize it. The controller/microprocessor receives an activating signal from the detection mechanism and in turn generates said control signal to recite the propelling mechanism.   The disrupting element is made of a rigid and hard material such as different metals or alloys, or suitable composite materials. The disrupting element is an elongate bar which may assume different cross-section shapes, e.g. blade-like (i.e. an edge thereof facing the center of the wall of the enclosure is narrower than the body thereof), a rectangle bar, cross-like, triangle-like, etc.   The RPG Disruption System (RDS) is suited for securing to the wall of the enclosure at different fashions. For example, it may extend from an edge of the wall with the disrupting element facing towards a center of the wall, or the RDS may be fixed at a central portion of the wall such that the disrupting element faces outwards (facing a respective edge of the wall).   The RPG Disruption System (RDS) is in the form of a module/cassette suited for modular attaching to the enclosure.   The disrupting element is propelled substantially parallel to the anvil. However, according to an option of the invention, the disrupting element is displaced non-parallel with respect to the anvil, e.g. by applying different amounts of explosive material or materials having different explosive properties. Likewise, there may be several initiation locations for sequential initializing of the explosive material.   The propelling speed of the disrupting element corresponds to the speed of the RPG and the actual distance of the disrupting element from the wall, whereby a fast RPG requires that the disrupting element by propelled faster or correspondingly increasing the distance of the disrupting element from the wall.   The RPG Disruption System (RDS) is fitted with a self test system to verify the status and perfection of the system.   The system is in the form of modules fitted for attaching to a wall of an enclosure, each module constructed as discussed hereinabove.       

     According to the present invention there is also provided a method for protecting an enclosure against RPGs, the method comprising the following steps: 
     a. Fixing one or more RPG Disruption modules (RDS), in close proximity to a wall of the enclosure facing an anticipated RPG threat, each module comprising a casing comprising an anvil accommodating a propelling mechanism for displacing said disrupting element in a plane substantially parallel to said wall; and an activating system for activating said propelling mechanism so as to propel the disrupting element towards an approaching RPG, to thereby neutralize it; 
     b. Initiating the system 
     c. Detecting an upcoming RPG threat at predetermined proximity to the wall; and 
     d. propelling the disrupting element towards a head portion of the RPG, to thereby prevent its detonator from activating the explosive. 
     Any of the above mentioned features referred-to in connection with the system and module may be applied in connection with a method utilizing same, respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, several embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic side view of a vehicle fitted with a protective system according to the present invention; 
         FIG. 2  is schematic side front of the vehicle of  FIG. 1 ; 
         FIG. 3A  is an isometric sectioned view of a warhead of an RPG; 
         FIGS. 3B and 3C  correspond with  FIG. 3A  and schematically illustrate two fashions of neutralizing the RPG; 
         FIG. 4A  is an enlargement of the portion marked IV in  FIG. 2 ; 
         FIG. 4B  is an enlargement of the portion marked V in  FIG. 1 ; 
         FIGS. 5A to 5D  are schematic side views of a vehicle fitted with a protective system according to the present invention, illustrating consecutive steps of neutralizing an approaching RPG; 
         FIGS. 6A to 6C  schematically illustrate variations of applying a protective system according to the present invention over a wall of an enclosure, a vehicle in the particular drawings; and  FIGS. 7A to 7C  are schematic illustrations of alternate propelling mechanisms; 
         FIGS. 7A to 7C  are sectioned isometric vies illustrating variations of propelling mechanisms for use in the system according to the present invention; and 
         FIGS. 8A to 8F  are exemplary cross sections of disrupting elements useful in a system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Attention is first made to  FIGS. 1 and 2  of the drawings illustrating an enclosure to be protected against RPG threats, said enclosure being in the particular example a vehicle designated  10 . However, an enclosure as referred to in the present invention is referred to in the broad aspect and includes all types of vehicles and structures. 
     The enclosure (vehicle)  10  comprises side walls  12 , rear wall  14 , front wall  16 , a roof  18  and a bottom (chassis)  20 . Several RPG Disruption Systems (RDS) according to the invention, generally designated  26 , are fitted on the vehicle, the structure of which will become apparent hereinafter. The RDS  26  are detachably fixed to the vehicle; typically to frame elements (structure beams) thereof, by bolts  28  or other fasteners, as illustrated in  FIGS. 4A and 4B . Other arrangements are possible to. For example, the RDS may be easily attachable/detachable or even collapsible, whereby the system is rapidly mounted and deployed into an operative state, whilst may be easily removed (or collapsed/folded) so as to facilitate easy maneuvering of a vehicle in tight areas, such as in alleys. 
     In the particular discussed embodiment the RDS  26  are fixed to the vehicle  10  at its top, above front door  30 A passenger door  30 B and rear door (not seen), in manner so as not to obstacle the doors or constitute any other disturbance to the operation of the vehicle or comfort of its passengers. As will be discussed hereinafter with reference to  FIGS. 6A to 6C , the RDS may be otherwise attached to the enclosure. 
     The RDS  26  are independent modules, easily mounted and detached for maintenance, replacement, etc. 
     As can best be seen. in  FIGS. 4A and 4B , each RDS module  26  comprises a housing  40  fitted with attachment portions in the form of two flanges  42  and  44 , designed for attaching to a wall of an enclosure. Thus, these flanges may assume other configurations depending on the intended enclosure. The RDS modules are parallely attached to the respective walls of the enclosure. 
     The RDS module  26  is made of rigid material such as metal and is formed with a trough-shaped anvil (e.g. inverted trough-like anvil portion  46 ) accommodating a disrupting projectile (e.g. downwardly facing disrupting element  48 ) secured within the anvil  46  by shims  52 . Intermediate the anvil  46  and the disrupting element  48  there is a propelling mechanism  56  (e.g. propellant, spring) which in the present example is an amount of explosive material fitted with a detonator  61 . It is seen that the disrupting element is secured at a plane substantially parallel to the respective wall, such that upon propelling ( FIGS. 5C and 5D ) it maintains its parallel position, i.e. remains at a substantially fixed distance from the wall. Likewise, the propelling mechanism is so designed as to propel the disrupting element  48  substantially parallel to the anvil  46 . Thus, explosive  56  is homogeneously distributed along the anvil  46 . Where a mechanical spring is used, this result is taken care of as well, as will be discussed herein after with reference to  FIGS. 7A to 7C . 
     As shown in  FIG. 4A , the trough-like anvil  46  comprises three closed sides and one open side, and the trough-like anvil  46  is oriented so that the open side is perpendicular relative to the wall  12  of the enclosure  10 . The propelling mechanism is located adjacent the closed side of the trough-like anvil  46  positioned opposite to the open side of the trough-like anvil  46 , and the disrupting element  48  is located adjacent the open side of the trough-like anvil  46 . The trough-like anvil  46  opens in a direction parallel to the wall  12  of the enclosure  10 . The propelling mechanism  56  is disposed between the anvil  46  and the disrupting element  48 . Further, the propelling mechanism  56  is disposed between a closed side of the anvil  46  is located opposite to the open side of the anvil  46  so that the propelling mechanisms propels the disrupting element  48  in the plane substantially parallel to the wall  12  of the enclosure  10 . The disrupting element  48  nests within a open side of the trough-like anvil  46 . 
     As can further be noted in  FIGS. 1, 2 and 6 , the vehicle/enclosure  10  is also fitted with an early detection sensor in the form of radar  60  for initiating the system upon launch of an RPG. Such a sensor may be of known design, for example a thermal detector, flare detector, blast detector, image detector, etc., whereby upon detection of a launched/approaching RPG the system is armed and is ready to handle the threat. Several such sensors may be provided, each facing a different sector, or the sensor may be suited for 360° coverage. Otherwise, the RPG Disruption System (RDS) may be manually initiated (e.g. by a commander of a vehicle) or it may normally set to an initiated, active state. The sensor  60  allows for the system to be maintained at a hibernating state until detection of the launch or approach of an RPG threat. This renders the system safer. 
     In addition, the system is fitted with a detection system (e.g. detector), for example, defining an imaginary plane ( 69  in  FIG. 5A ) covered by the disrupting element  48 , for generating an activating signal to instantaneously propel the disrupting element. The detection system in  FIGS. 2 and 4A  is in the form of an electronic curtain created by detectors  70 , namely optic sensor, magnetic sensor, RF sensors and the like. Such sensors may be located at other locations too, e.g. opposite the module  26 , etc. The detection system may also be in the form of a mechanical barrier defining said imaginary plane, e.g. a fine mesh ( 69  in  FIGS. 5A-5D ), a web or grid, whereupon tension or pressure applied to said material, or piercing same, generates the activating signal. The material may be in the form of a sheet of material embedded with or made of conductive material or coating (e.g. special paints), etc. 
     A controller (microprocessor)  75  ( FIGS. 1 and 2 ) is provided for coordinating and processing the signals received from the early sensor  60 , the imaginary plane penetration detection system and generating a propelling signal to timely propel the disrupting element  48  so as to anticipate the upcoming RPG threat. The controller is also competent for performing periodic or on-demand tests of the system and for minimizing the chance of false alert of the different detectors. Also, the controller is associated with safety parameters of the system, e.g. the system cannot be operated when the doors of a vehicle fitted with same are open, etc. 
     An example is provided for understanding the principle of the present invention, further attention is directed to  FIG. 3A  illustrating a sectioned isometric view of a typical RPG warhead generally designated  80 . The warhead is a shaped charge comprising a cylinder of explosive  82  with a metal-lined conical hollow (liner)  84 , an inner metal envelope cone  86  which together constitute a hollow space  88 , a detonator  94  in conjunction with the explosive  82 , said detonator  94  being electrically coupled to a Piezo-electric sensor  98  at a fore end of the warhead via a conductive aerodynamic cover  90  and the inner metal envelope cone  86 . 
     Upon impact of the Piezo-electric sensor  98  with a target, an electric current generates and is conducted via the conductive aerodynamic cover  90  and said inner metal envelope cone  86  and said liner  84  to ignite the detonator  94  resulting in detonation of the explosive  82 . Accordingly, disabling/truncating the Piezo-electric sensor  98  ( FIG. 3B ) or creating an electric shortcut between the aerodynamic cover  90  and the inner metal envelope cone  86  (by their deformation so as to engage with one another;  FIG. 3C ) will result in failure of the detonator  94  to ignite and the explosive charge  82  from exploding. It should be noted that in some case rather than liner and envelope conducting element, electric conductivity is by means of wiring. 
     In operation, when an enclosure (a vehicle in the present example) is fitted with an RDS system according to the present invention, the system (controller  75 ) is set to an ‘on’ position and upon entry of the vehicle  10  into a hostile arena the early detection sensor  60  is activated. Detection of a launch of an RPG or its approach will arm the system ( FIG. 5A ), anticipating the nearing RPG threat. At the instance of penetration of the fore end of the warhead  80  of the RPG (i.e. the Piezo-electric sensor  98 ) into the imaginary plane  69  ( FIG. 5B ), the detectors  70  generate a signal to the controller  75  which in turn generates a propelling signal to instantly propel the disrupting element  48  by igniting the explosive material  56  ( FIG. 5C ) to strike against the warhead  80 , resulting in disabling/truncating the Piezo-electric sensor  98  or creating an electric shortcut between the aerodynamic cover  90  and the inner metal envelope cone  86  ( FIG. 5D ), resulting in failure of the detonator  94  to ignite and the explosive charge  82  from exploding. 
     RPGs in the arena typically fly at substantially low speeds, thus propelling the disrupting element  48  at substantially high speed, whereby a module according to the present invention may be fitted adjacent (in close proximity) to the wall of the enclosure to be protected, whereby the overall dimensions of the enclosure are less affected. 
     Furthermore, by propelling the disrupting element  48  at a substantially high speed, the RPG threat becomes neutralized by preventing initiation of the explosive material (as opposed to deflecting or breaking the threat). This takes place, as explained herein above, by disrupting the electric initializing of the explosive either by breaking or truncating the Piezo-electric sensor from the RPG or by causing an electric shortcut by deforming the aerodynamic cover  90  and the inner metal envelope cone  86 . Accordingly, there is no need for high momentum of the disrupting element. 
     Turning now to  FIGS. 6A to 6C  there are illustrated exemplary configurations of fitting a vehicle with RDS according to the present invention. In  FIG. 6A  the vehicle  100  is fitted with a front RDS module  102  fitted at a front edge of the front door  104  and another RDS  108  fitted at a rear end of the vehicle, behind the rear door  110 , whereby the RDS  102  and  108  are substantially vertical and face one another with a rear of the vehicle protected by a horizontally extending RDS  114  at a top end thereof. In the example of  FIG. 6B  the RDS  116  and  118  extend vertically at a center of the vehicle  120 , in a back-to-back orientation, such that rear RDS  116  covers the rear door portion and the front RDS  118  covers the front of the vehicle, respectively.  FIG. 6C  illustrates an alternative embodiment for protecting a vehicle  123 , comprising a front bottom RDS  124 , a front top RDS  126 , a rear bottom RDS  128  and a rear top RDS  130 , respectively mounted on the front door  134  and the rear door  136 . 
       FIGS. 7A to 7C  illustrate alternative modifications of propelling mechanisms for propelling of the disrupting element  48 . In  FIG. 7A  the explosive charge is replaced by an array of compression springs  146  maintained at their normally compressed state, whereby upon retraction of several retention pins  148  (e.g. by a solenoid) the springs  146  expand so as to propel the disrupting element  48 . In  FIG. 7B  the propelling mechanism is in the form of a ‘magnetic spring’ composed of one or more magnets  150  with their polarity opposite that of the disrupting element  48 . The magnets may be permanent magnets (in which case the disrupting element is retained by a mechanical arresting arrangement as discussed hereinbefore), or charged per demand, i.e. an array of coils is provided (not shown) for generating a powerful magnetic field with directional orientation so as to propel the disrupting element. In  FIG. 7C  the propelling mechanism is in the form of a pneumatic spring comprising one or more compressed gas cylinders  156 , with the disrupting element  48  retained within the anvil portion  46  of the housing  40  by retention pins (not seen), whereby rapid discharge of the high-pressurized gas entails rapid propelling of the disrupting element, with tear/break of the retention pins. 
     Turning now to  FIGS. 8A to 8F  there are illustrated exemplary cross sections of disrupting elements designated  48   a  to  48   f , respectively, useful in a system according to the present invention, these being examples only. 
     Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the invention, mutatis mutandis.