INTRODUCTION

The present invention relates to a method for simulating weapon ef fect against a speci fic target comprising at least one three dimensional model of a warhead and a three dimensional model of a target where the model of the warhead is adapted so that the weapon ef fect against the target for each fragment of the warhead is simulated .

BACKGROUND OF THE INVENTION, PROBLEM DEFINITION AND PRIOR ART

Modelling of performance of a weapon system is of great importance for a wide variety of tasks such as to develop doctrines such as tactical doctrines , to learn more about a system for further research and development ef forts , to evaluate a systems performance for a speci fic target or in a speci fic situation, and to train users of the speci fic system .

According to one traditional method, the task of evaluating the ef fectiveness of a weapon system in a combat engagement is performed using a two-step approach . The first step is to create an error budget for the system being analyzed, and the second step is to use that error budget to evaluate the probability of defeating a target .

An error budget is a collection of forces and ef fects that contribute to a fired round missing its intended aim point . These forces and ef fects are described through equations that calculate their downrange miss distances . The values of the results are then root-sum-squared into three categories based on how the errors mani fest themselves in a scenario . These categories are round-to-round, burst-to- burst , and engagement-to-engagement . These values are then used in further analysis .

Once an error budget has been created, it is used with one of two methodologies to calculate the probabi lity of defeating a target . The method used to analyze the weapon depends on the complexity of the firing situation . One method is a statistical approach that is used in direct fire situations with simple targets . The other method is an iterative solution that is used in more complex scenario or with air burst munitions .

An example of a system and method for evaluating the performance of a weapon platform is described in patent application US 9 , 830 , 408 Bl . A drawback with currently existing solutions according to 9 , 830 , 408 Bl is that the described system and method does no di scloses that the weapon ef fect is simulated for each individual fragment generated by the warhead . The patent application neither discloses a closed-loop system .

When a new warhead is design it is conventional to simulate the fragmentation performance of the warhead with speci fic finite element simulation software such as LS-DYNA or other software used to simulate complex real world, highly nonlinear, transient dynamic physical behaviour . Drawback with these kind of simulations are , as an example , that the target position relative the warhead, the velocity of the target and the warhead and that the physical characteristics of the warhead are not included in the simulation .

Further problems which the present invention aims to solve will be elucidated below in the detailed description of the various embodiments .

OBJECT OF THE INVENTION AND ITS DISTINCTIVE FEATURES

The invention relates to a method for simulating weapon ef fect against a speci fic target comprising at least one three dimensional model of the warhead and a three dimensional model of the target where the model of the warhead is adapted so that the weapon ef fect against the target for each fragment of the warhead is simulated .

According to further aspects of the improved method for simulating weapon ef fect against a speci fic target ; the weapon ef fect of each fragment is simulated in relation to the position of the target . an estimate of the probability that a speci fic fragment of the warhead ef fects the target is calculated . an estimate of the probability that a speci fic fragment of the warhead hits the target is calculated . the probability for that a speci fic fragment of the warhead hits the target is visuali zed as a heat map of the warhead where each speci fic fragment is illustrated with a colour relating to the probability .

According to further embodiments of the invention the invention also comprises a computer program product wherein the method for simulating weapon ef fect against a speci fic target comprises at least one model of a warhead implemented in program code .

ADVANTAGES AND EFFECTS OF THE INVENTION

Advantages of the present invention includes that the simulation is performed in three dimensions compared to the conventional two dimensions . The actual performance of a warhead is dependent upon when the warhead is initiated . Depending upon the actual situation the warhead could approach the target perpendicular to the target or parallel to the target and all the alternatives between a full perpendicular approach and a fully parallel approach . With a simulation of the weapon ef fect in a complete system chain it is possible to optimi ze the position of the fragments , the pre- fragment , si ze of the fragments and number of fragments of the warhead for a speci fic situation or type of engagement .

DRAWING FIGURES

The invention will be described in greater detail below with reference to the attached figures , in which :

Fig . 1 shows a block diagram of a closed loop weapon system evaluation method according to one embodiment of the invention . Fig . 2 shows a heat map of the weapon ef fect towards a target of individual fragments of a warhead for a first position relative to the target according to one embodiment of the invention .

Fig . 3 shows a heat map of the weapon ef fect towards a target of individual fragments o f a warhead for a second position relative to the target according to one embodiment of the invention .

DETAILED DESCRIPTION OF EMBODIMENTS

Fig . 1 shows a block diagram of a closed loop weapon system evaluation method 10 according to one embodiment of the invention . The closed loop weapon system evaluation method 10 comprises a number of modules describing the weapon system . The modules of the closed loop weapon system evaluation method 10 could include , but is not limited to , the following modules ; a sight unit 20 , a fire control unit 30 , a launch unit 40 , a proj ectile traj ectory unit 50 , a warhead unit 50 of said proj ectile unit , a target unit 60 . The closed loop weapon system evaluation method 10 is collectively arranged in a data processing system such as a computer or other calculating unit arranged to carry out sequences of arithmetic or logical operations automatically via computer programming .

The sight unit 20 represent a model of a sight of weapon system such as a gun . The sight unit 20 comprises models of radar sensors , models of electro optical sensor/ sight , and/or a model of a laser rangefinder .

The fire control unit 30 represent a model of a fire control system of a weapon system comprising at least one of a model of a ballistic calculator, weather model s , model of prediction fi lters , models of ship gyro for speci fic modelling for ship mount systems .

The sight unit 20 and the fire control unit 30 could also be modelled as a combined entity .

The launch unit 40 represent a model of a launch unit , such as a gun . The launch unit is used for launching a proj ectile from the launch unit . In the case the launch unit is a gun the components of the gun could include models for an initiator, a propellant , a proj ectile and a barrel . At ignition the propellant is ignited and burned to generate gas and a gas pressure acting upon the proj ectile arranged in the barrel . When the pressure achieves a certain threshold the proj ectile starts to move in the barrel . The propellant continuous to generate gas acting upon the proj ectile until the proj ectile leaves the gun barrel . The launch unit 40 could also comprise models of traverse speed and limitations , elevation speed and limitations , rate of fire , dispersion etc .

The proj ectile traj ectory unit 50 comprises a model of a proj ectile traj ectory comprising ballistic models adapted for di f ferent proj ectile characteristics .

The warhead unit 60 comprises a model of the warhead of the proj ectile . The dynamic , or transit dynamic, properties of a warhead could be calculated in a finite element program such as LS-Dyna . The results from a transit dynamic calculation, or from other simulation, are represented in the warhead unit 60 by a model comprising at least one model representing at least one of fragmentation velocity, fragmentation si ze , fragmentation shape , fragmentation traj ectory, and fragmentation ballistics and/or other additional models/representation regarding the fragments physical performance . Further the proj ectile could be modelled with regards to muz zle velocity, rotational velocity, Cd coef ficient ( drag coef ficient ) and/or other additional models regarding the proj ectiles physical performance .

Further the fuze of the ammunition could be modelled with parameters for a time fuze such as time dispersion, auto destruct functionality and function probability of time fuze , and/or other additional models regarding the performance of the time fuze . Further the fuze could be modelled with parameters for a point detonation fuze such as point detonation delay, point detonation target hardness requirement , point detonation function probability for a point detonation fuze , and/or other additional models regarding the performance of the point detonation fuze . Further the fuze could be modelled with parameters for a proximity fuze such as detection area radius and shape for a proximity fuze, probability of fuze trigg within detection area for a proximity fuze, dispersion of burstpoints within detection area for a proximity fuze and overall probability of fuze function for a proximity fuze, and/or other additional models regarding the performance of the proximity fuze.

The target unit 70 could comprise models for path, speed, geometry, materials and vital components/Sensitive section of the target and/or other additional models regarding the performance and/or construction of the target.

Fig. 2 shows a heat map of the probability of a specific fragment hitting the target 100, i.e. the weapon effect towards a target of individual fragments of a warhead for a first position relative to the target. A heat map shows the magnitude of a phenomenon, in this case the probability, as colour, or other visual indication, in two dimensions. For this specific figure the magnitude is illustrated as a varying density of lines. Each individual fragment is shown with the probability that the fragment effects and/or hits the target wherein the fragment visualized with a higher density of lines, such as fragment 102, have a very high probability to effect and/or hit the target. Fragments visualized with a slightly less density on the lines, such as fragment 104, have a high probability to effect and/or hit the target. Fragments visualized with a low density of lines, such as fragment 106, have a low probability to effect and/or hit the target. Fragments visualized with no lines at all, such as fragment 108, have more or less no probability to effect and/or hit the target.

Fig. 3 shows the probability of a specific fragment effecting and/or hitting the target 100", i.e. the weapon effect towards a target of individual fragments of a warhead, for a second position relative to the target. Each individual fragment is shown with the probability that the fragment effects and/or hits the target wherein the fragment visualized with a higher density of lines, such as fragment 102, have a very high probability to effect and/or hit the target. Fragments visualized with a slightly less density on the lines, such as fragment 104, have a high probability to effect and/or hit the target. Fragments visualized with a low density of lines, such as fragment 106, have a low probability to effect and/or hit the target. In the specific shown figure there is not fragments with more or less no probability of effecting and/or hitting the target, such as shown in figure 2, i.e. the described scenario thus show a scenario where more or less every fragment have the probability to effect and/or hit the target.

When simulating the weapon effect it is possible to identify which specific fragments or pre-fragments of the warhead that contributes to the weapon effect to the target. Fragments that does not contribute to the weapon effects, such as fragment 108, could be removed from the warhead with limited or no negative effect of the performance of the warhead. By simulating the complete system chain including at least a model of the target, the position of the projectile relative the position of the target, the speed of the projectile, the speed of the target, the arrangement of the fragments of warhead of the projectile and the distribution of the fragments of the warhead when the warhead is initiated a complete simulation model of a specific weapon engagement is possible and the warhead could be optimized. Optimization of the warhead could include selection of the size of the fragments of the warhead and for pre fragmented warhead the size of the specific fragments, the number of fragments, the distribution of fragments etc. Specifically it is possible to remove fragments that is not contributing to the weapon effect of the warhead and thus reduce the cost to produce the warhead, the weight of the warhead etc.

Traditionally a warhead is simulated in a dynamic simulation environment to optimize the distribution of the fragments from the warhead and/or the fragmentation of the warhead when the warhead is in a static stationary position . The optimi zation is thus performed to improve the distribution of fragments or pre- fragments to achieve a preferable distribution pattern for a general utili zation of the warhead . With a simulation of the weapon ef fect in a complete system chain it is possible to optimi ze the position of the fragments , si ze of the fragments and number of fragments of the warhead for a speci fic situation or type of engagement .

In a simulation it is possible to set the speed of the proj ectile and/or the target and in an example the speed of the proj ectile could be in the range of 550 m/ s to 650 m/ s and the rotation of the proj ectile could be in the range 3800 rad/ s to 4600 rad/ s and the speed of the target could be in the range 10 m/ s to 30 m/ s .

ALTERNATIVE EMBODIMENTS

The invention is not limited to the embodiments speci fically shown, but can be varied in di f ferent ways within the scope of the patent claims .

It will be appreciated, for example , that the modules of the closed loop weapon system evaluation method could be varied and how the modules are arranged, as well as the integral modules and implementation, is adapted to the needs of the user and/or customer of a closed loop weapon system evaluation method . The closed loop weapon system evaluation method could also be changed depending upon other current design characteristics .

Embodiments of the present invention can take the form of an entirely hardware embodiment or an embodiment containing both hardware and software elements . For the purposes of this description, a computer usable or computer readable medium can be any apparatus that can contain, store , communicate , propagate , or transport the program for use by or in connection with the instruction execution system, apparatus , or device . The medium can be an electronic, magnetic, optical , electromagnetic, infrared, or semiconductor system ( or apparatus or device ) or a propagation medium . Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape , a removable computer diskette , a random acces s memory (RAM) , a read-only memory (ROM) , a rigid magnetic disk and an optical disk . Current examples of optical disks include compact disk-read only memory ( CD-ROM) , compact disk- read/write ( CD-R/W) and DVD . The medium could also be a service arranged to an electronic communication means such as Internet or a cloud service .

A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus . The memory elements can include local memory employed during actual execution of the program code , bulk storage , and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution . Input/output or I /O devices ( including but not limited to keyboards , displays , pointing devices , etc . ) can be coupled to the system either directly or through intervening I /O controllers . Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks .