SYSTEMS AND METHODS FOR ASSESING VULNERABILITY OF NON-LINE OF SIGHT TARGERTS

Abstract

A computer-implemented system and method of determining the vulnerability of an asset includes determining an elevation surface surrounding an asset. A target point and aim point are selected on the asset and ballistic trajectories are determined for a particular projectile. A plurality of trajectory height surfaces that are rotationally symmetric about the asset and having a cross-section corresponding to the projectile trajectory for the selected range. A corrected elevation surface is generated for each range based on the trajectory height surface for the particular range. An observer view surface is generated from the plurality of corrected elevation surfaces, and is combined with the target visibility surface to generate the target vulnerability surface.

Description

FIELD OF INVENTION

This disclosure concerns determining vulnerabilities of assets to rifle fire and other ballistics from geographic positions surrounding the assets.

BACKGROUND

Security of industrial and utility assets and infrastructure can be an important consideration in operation of such assets and infrastructure. There has been an effort to place fencing and earthen berms around many facilities with the intent of protecting the assets and personnel inside the facilities. However, the protection is typically only designed to shield sight lines within a short distance of the facility. Such obstructions are not optimal as long range rifles can be used to hit targets outside of the shooters sight line. With recently developed armor piercing ammunition, many of the otherwise protected assets are effectively within range. Thus a systems and methods for determining vulnerabilities from locations that do not have a line of sight to the target are desirable.

SUMMARY OF THE INVENTION

The present disclosure concerns determining effective rifle sight lines for a geographic area surrounding assets and infrastructure. According to one aspect of the present disclosure, modifications to the elevation of surrounding terrain are made to account for bullet trajectory and drop. Thus, locations are identified in the surrounding area that do not have direct lines of sight, but can nevertheless serve as shooting location for a rifleman intent on hitting the asset.

A computer-implemented system and method of determining the vulnerability of an asset includes determining an elevation surface surrounding an asset. A target point and aim point are selected on the asset and ballistic trajectories are determined for a particular projectile over a plurality of isotropic bands at various ranges. A plurality of trajectory height surfaces are generated for the various ranges that are rotationally symmetric about the asset and having a cross-section corresponding to the projectile trajectory for the particular range. A corrected elevation surface is generated for each range based on the trajectory height surface for the particular range. An observer view surface is generated from the plurality of corrected elevation surfaces, and is combined with the target visibility surface to generate the target vulnerability surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, structures and methods are illustrated that, together with the detailed description provided below, describe aspects of a system determining the vulnerability of assets to non-line of sight fire, and related methods. It will be noted that a single component may be implemented as multiple components or that multiple components may be implemented as a single component. The figures are not drawn to scale and the proportions of certain parts have been exaggerated for convenience of illustration. Further, in the accompanying drawings and description that follow, like parts are indicated throughout the drawings and written description with the same reference numerals, respectively.

FIG. 1 (“FIG. 1”) illustrates a diagram of system 100.

FIG. 2 illustrates a subject asset 102.

FIGS. 3A-3E illustrate sight lines and trajectories for various obstructions 301-305.

FIG. 4 illustrates a filtered raster 400.

FIG. 5 illustrates an aim visibility surface 500 overlaid on elevation surface 404.

FIG. 6 illustrates a target visibility surface 600 overlaid on elevation surface 404.

FIG. 7 illustrates a comparison of aim visibility surface 500 and target visibility surface 600.

FIG. 8 illustrates a trajectory height surfaces 800 overlaid on elevation surface 404.

FIG. 9 illustrates a corrected elevation surface 900.

FIG. 10 illustrates observer view surface 1002.

FIG. 11 illustrates target vulnerability surface 1100 overlaid on elevation surface 404.

FIG. 12 illustrates target visibility surface 600 overlaid on target vulnerability surface 1100.

FIG. 13 illustrates a method 1300 for determining asset 102 vulnerability.

DETAILED DESCRIPTION

With reference to FIG. 1, a system 100 for evaluating the vulnerability of assets 102 includes a computing device 104, which can be a general purpose computer or specialized computer, and can be portable, desktop or handheld. The computer includes a processor 106 and non-transient computer readable medium (CRM) 108, which can include without limitation hard drives, random access memory, flash-based drives, caches, registers, optical drives, or other form of non-transient computer-readable media.

The evaluation of vulnerability of an asset 102 includes providing geographic data 110 including but not limited to elevation data of the geographic region of interest surround the asset 102. Asset data 112 includes the structure, dimensions, target and aim points, and other information concerning asset 102. Ballistic data 114 includes data concerning the specifications of the particular projectile. This can include a trajectory height function dependent on the distance traversed by the projectile. The geographic data 110, asset data 112, and ballistic data 114 can be stored on the CRM 108, such as in storage locations 116a, 116b, 116c, etc. Processor 106 can execute instructions 118 written on CRM 108, including those instructions described herein, to determine target vulnerability 120 and protective barrier placement 122 that would mitigate against potential vulnerabilities by blocking one or both of the shooter's ability to see the aim point or hit the target point with a projectile such as a rifle bullet.

With reference to FIG. 2, asset 102 has a warning light 130 at its highest point, which is at a height of 24 meters above the ground surface 132. In this case, the aim point 200 can be selected as the highest point of the particular asset 102, which would be the minimum amount of the asset 102 that the potential shooter would be required to see in order to determine the position of the remainder of the asset 102. When a potential shooter is able to see only the aim point 200, the remainder of the asset 102 can be obstructed by the terrain between the potential shooter and the asset 102. The selected target point 202 is 12 meters above the ground and is at the equatorial latitude of the tank. The asset 102 has a diameter of 20 meters. The illustrated target point 202 and aim point 200 are non-limiting and can be selected at any desired points on the asset 102. The aim point 200 is preferably above the target point 202, and as described further herein thresholds can be chosen under which further analysis for the selected target point 202 and aim points 200 is not necessary. Target points 402 can be chosen based upon factors including but not limited to known structural vulnerabilities of the asset, intelligence gathering, the likelihood of a non-failure mode strike by a projectile at the selected target point, and others. Aim points 200 can likewise be chosen at any reference point on the asset 102, however, the amount of available terrain from which to view aim points 200 decreases as the selected aim point 200 moves further below the highest possible aim point 200. Conversely, selecting the highest possible aim point 200 provides the maximum amount of possible terrain from which to view the selected aim point 200.

FIGS. 3A-3E illustrate sight lines and trajectories from a shooter firing and viewing from 1 meter above the ground to an asset 102 over different geographic obstructions 301-305 having different heights and shapes. In FIG. 3A the target point 202 is visible along direct sight line 310, and so it is accessible to a shooter at that location. In FIG. 3B, the target point 202 is not visible along direct sight line 310, but the aim point 200 is visible along the indirect sight line 312. In this case, a shooter can still hit the target point 202 as the projectile trajectory 314 is not impeded by obstruction 302. The locations from which a shooter cannot view the target point 202 but can see the aim point 200 and can reach the target point 202 over intervening obstructions with the projectile trajectory 314 can be determined according to the present teachings. In FIGS. 3C through 3E, at least one of the trajectory 314 or the indirect sight line 312 are blocked by intervening obstructions 303, 304, 305.

With reference to FIG. 4, a filtered raster 400 corresponding to a three dimensional elevation surface is created from detailed raster data. The initial detailed raster data is obtained from multiple Light Detection and Ranging (LIDAR) files, which can be simple ASCII files wherein each line includes a coordinate (x, y, z) wherein x and y are latitude and longitude and z is the altitude for the particular (x, y) coordinate. Other forms of files, including without limitation CAD files or GIS files, can include data that can be implemented according to the present teachings. The multiple LIDAR files each cover separate areas within the region 402 surrounding the asset 102, which is disposed in the center of the surrounding region 402. The depicted surrounding region 402 is circular with a radius of 5000 meters. Any data contained within the LIDAR files outside of the surrounding region 402 can be masked off and ignored.

The initial raster data is filtered by removing anomalies and noise due to, for example, conversion of raster data and incorrect surface elevations from power lines and other localized objects disposed within the surrounding region 402. A resulting filtered elevation surface 404 is generated from the filtered raster data, and can be used to evaluate asset 102 vulnerabilities as described herein.

With reference to FIG. 5, an aim visibility surface 500 is determined over the elevation surface 404, representing the locations on the surface 404 from which an potential shooter firing and viewing from a height of 1 meter can see the aim point 200 of the asset 102, which in the illustrated case corresponds to the surface elevation at the asset plus 24 meters. A location on the elevation surface 404 is part of the aim visibility surface 500 if a line from the aim point 200 of the asset 102 to a point 1 meter above the potential shooter's particular location on the elevation surface 404 is unobstructed. At such a location on the elevation surface 404, the potential shooter will have an unobstructed line of sight to the aim point 200.

With reference to FIG. 6, a target visibility surface 600 is determined over the elevation surface 404, representing the locations on the surface 404 from which a potential shooter, again viewing from a height of 1 meter, can see the target point 202 of the asset 102, which in the illustrated case corresponds to the surface elevation at the asset plus 12 meters. A location on the elevation surface 404 is part of the target visibility surface 600 if a line from the target point 202 of the asset 102 to a point 1 meter above the ground at the particular location on the elevation surface 404 is unobstructed. At such a location on the elevation surface 404, the potential shooter will have an unobstructed line of sight to the target point 202.

With reference to FIG. 7, a comparison of the aim visibility surface 500 and the target visibility surface 600, which in the illustrated case is overlaid on aim visibility surface 500, exposes the locations 501 that are within the aim visibility surface 500 and not the target visibility surfaces 600. A shooter at any of those locations has a line of sight to the aim point 200 but not the target point 202, rendering those locations 501 potential candidates for trajectory-assisted firing upon the asset 102. In those locations 501, the shooter cannot see the target point 202 but can potentially reach the target point 202 with the benefit of the aim point 200 and a shot fired along the correct trajectory, which trajectory has boundary conditions satisfying the selection of the target point 202 and the elevation of the shooter's rifle and viewpoint. The locations 501 combined can be required to have a threshold amount of surface area such that below the threshold, no further determination of possible vulnerabilities according are desirable as the amount of risk is acceptably low. In such a cases the potential locations for an obstructed shooter, i.e. one that has view of the aim point 200 but not the target point 202, are few enough that they do not add sufficiently substantial risk in addition to the risk posed from the target visibility surface 600 alone. Such a threshold can be predetermined at any desirable amount, including but not limited to 1 percent, 5 percent, 10 percent or 25 percent of the total surface area of the target visibility surface 600.

With reference to FIG. 8, several steps are performed in order to create a corrected elevation map for evaluating vulnerabilities. A set of trajectory height surfaces 800 are created. These surfaces 800 can be isotropic, and can correspond to the path of the projectile from a point on the outer edge of the ring to the target point 202 and swept one revolution about the target point 202. One trajectory height surface 800 is generated for each of several circular rings surrounding the asset 102, the rings starting at 500 meters radius and extending to 1900 meters, each ring 100 meters thick along the radial direction. FIG. 8 shows the 1900 meter trajectory height surface 800 overlaid on elevation surface 404.

With reference to FIG. 9, a set of corrected elevation surfaces 900 is generated based on the set of trajectory height surfaces 800. One corrected elevation surface 900 is generated for each trajectory height surface 800, from 500 to 1900 meters, by subtracting the height of the trajectory height surface 800 from the corresponding base elevation of elevation surface 404. A corrected region 902 can be seen in FIG. 9, which again corresponds to the 1900 meters ring, in which the elevation has been corrected and appears darker than in elevation surface 404. In that region 902, the altitude of the terrain is lower than that found in surface 404. The trajectory of the projectile can be obtained by determining projectile data, such as ballistic information including but not limited to the shape of the projectile, ballistic coefficient, projectile diameter, weight composition, and muzzle velocity. Such data can be obtained from a variety of sources, including but not limited to modeling software. In addition, results from models can further be curve-fit in order to obtain a finite order polynomial with which to calculate the surfaces 800. In the illustrated case, projectile trajectory was fit to a fifth order polynomial. It should be noted that the present teachings can be applied to a variety of rifle cartridges or to small arms such as rocket propelled grenades, infantry mortars, light cannon and indirect machine gun attacks. Further, corrected altitude can be performed on a location by location basis, rather than in wide rings. In such an approach, trajectories are calculated incrementally for each position in the region, and the corrected altitude surface is generated for each individual position.

With reference to FIG. 10, from each of the corrected elevations, an observer view is generated. The range for each observer view is one of fifteen 100 meter thick visibility rings surrounding the asset 102, with the inner radius chosen as the coordinate for which the corresponding elevation is selected for the ring. Other points can be selected for the elevation calculation. The outer ring corresponds to the potential shooter's view for 1900 to 2000 meters and the inner ring corresponds to the view for 500 to 600 meters from the asset 102. The highlighted portions within each ring correspond to the locations where an observer at the target point 202 can view the potential shooter viewing and firing from 1 meter elevation over the corrected elevation. The rings 1000 can be joined, for example by a logical OR function wherein a coordinate is part of an observer view surface 1002 if it is visible within its respective ring 1000.

With reference to FIG. 11, the observer view surface 1002 can be combined with the target visibility surface 600 to create target vulnerability surface 1100. Locations on the target vulnerability surface 1100 are locations where either the target point 202 is visible or the aim point 200 is visible and the target point 202 is reachable with a projectile shot along the correct trajectory. With reference to FIG. 12, the target visibility surface 600 is overlaid on target vulnerability surface 1100 in order to illustrate the additional area 1200 from which a potential shooter can reach the target point 202. This additional area corresponds to surface that is part of the target vulnerability surface 1100 but not the target visibility surface 600. In the current example, the increase in surface area over the target visibility surface 600 is 23 percent. It should be noted that the various surfaces referred to herein, such as the target vulnerability surface 1100 or target visibility surface 600, need not be contiguous, and can have one or more separate domains.

With reference to FIG. 13, a method 1300 for determining the vulnerability of an asset includes receiving high resolution elevation data for the asset and the surrounding area of interest in step 1302. In step 1304, ballistic trajectory data is received, which data can be determined by simulations of projectile shots and subsequent curve fitting of the resulting data to a curve that can be used to describe the projectile's trajectory as a function of its position relative to the asset 102. In step 1306, the position of the aim point 200 and target point 202 of the asset 102 are selected. In step 1308, an aim visibility surface 500 is created from the elevation map 404. In step 1310, a target visibility surface 600 is created from the elevation map 404. In step 1312, the target visibility surface 600 is compared to the aim visibility surface 500, for example to determine whether sufficient addition surface area is present in the aim visibility surface 500 over the target visibility surface 600 to justify continued analysis. In one aspect of the present teachings, step 1312 can be omitted and the other steps described herein can be performed without limitation.

In step 1314, a set of trajectory height surfaces 800 are generated, one each for a series of ranges from an inner range to an outer range. The trajectories used to form the trajectory surfaces 800 can be calculated from a curve fit polynomial as described herein, with boundary conditions that one end be at the target point 202 and the other at a predetermined elevation at a location disposed at the particular range. The trajectories are swept around the asset 102 so to form a rotationally symmetric surface 800 such that a cross-sectional view of the surface 800 along the radial direction exposes the trajectory used to form the surface 800. In step 1316, a set of corrected elevation surfaces 900 are determined, one for each of the selected ranges, using the trajectory surface 800 for the particular range. In step 1318, a set of observer point visibility surfaces are generated for each of the plurality of ranges. In step 1320, all of the visibility surfaces of the various ranges are combined to form the observer view surface 1002. In step 1322, the target visibility surface 600 and observer view surface 1002 are combined to form a target vulnerability surface 1100. In step 1324, the target visibility surface 600 is subtracted from the target vulnerability surface 1100 in order to illustrate the additional area 1200 from which a potential shooter can reach the target point 202.

The vulnerability analysis disclosed herein can be performed based on multiple targets in an area. Such an analysis could involve trajectory height surfaces radiating each of the target assets instead of a single target point. The methods disclosed herein can also be used to determine effective locations for visual and ballistic barriers.

The present teachings can be used to determine maximum distances from the asset 102 that could damage the asset 102 based on penetration angle, terminal energy and target shell material. Further, the present teachings can be implemented to determine the effective impact area based on maximum penetration angle of the projectile. The calculations performed herein can be extended to other target shapes, such as vertical, horizontal, and flat cylinders.

In the present disclosure, reference numerals followed by alphabetic indices refer to one of the illustrated elements, while use of the reference numeral without the alphabetic indices refer to one or more of the illustrated elements. For the purposes of this disclosure and unless otherwise specified, “a” or “an” means “one or more.” To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. As used herein, “about” will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term. From about A to B is intended to mean from about A to about B, where A and B are the specified values.

The description of various embodiments and the details of those embodiments is illustrative and is not intended to restrict or in any way limit the scope of the claimed invention to those embodiments and details. Additional advantages and modifications will be apparent to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's claimed invention.

Claims

1. A computer-implemented method of determining the vulnerability of an asset, comprising:

generating an elevation surface for a region surrounding an asset having elevations;

determining a target point and aim point of the asset;

determining ballistic trajectories for a plurality of distances from the asset to the target point;

generating a plurality of trajectory height surfaces rotationally symmetric about the asset and having a cross-section with a first end at the target point and second end at the radially outer edge of the surface at a distance corresponding to one of the plurality of distances from the asset;

generating a plurality corrected elevation surfaces by subtracting each of the trajectory height surfaces from a respective elevation surfaces; and,

generating an observer view surface from the plurality of corrected elevation surfaces.

2. The method of claim 1, further comprising:

determining a target visibility surface based on the elevation surface and the target point.

3. The method of claim 2, further comprising:

determining a target vulnerability surface based on the target visibility surface and observer view surface.

4. The method of claim 2, further comprising:

determining an aim visibility surface based on the elevation surface and aim point; and,

comparing a surface area of the aim visibility surface and a surface area of the target visibility surface.

5. The method of claim 1, wherein the step of determining a target point and aim point of the asset includes selecting the highest visible point on the asset as the aim point.

6. The method of claim 1, wherein the step of determining a target point and aim point of the asset includes selecting the aim point at a location above the target point.

7. The method of claim 1, wherein the generating an observer view surface step includes selecting one of the plurality corrected elevation surfaces corresponding to one of the plurality of distances from the asset and determining whether locations at the one of the plurality of distances from the asset have an unobstructed line of sight to the target point over the selected one of the corrected elevation surfaces.

8. The method of claim 7, wherein the generating an observer view surface step includes, for each corrected elevation surface, determining whether locations at one of the plurality of distances from the asset have an unobstructed line of sight to the target point over the selected one of the corrected elevation surfaces.

9. The method of claim 1, wherein the determining ballistic trajectories step includes performing a curve fit calculation based on ballistic trajectory data to obtain a trajectory function, and calculating the trajectories based on the functions.

10. An article of manufacture comprising:

a non-transient computer-readable medium including instructions thereon that upon execution by a processor: determine an elevation surface for a region surrounding an asset; determine a target point and aim point of the asset; determine ballistic trajectories for a plurality of distances from the asset to a target point on the asset; generate a trajectory height surfaces for each of a plurality of ranges having a radial distance from the asset, the trajectory height surfaces being rotationally symmetric about the asset and having a cross-section with a first end at the target point and second end at a ballistic firing point at an outer edge of the trajectory height surface; generate a corrected elevation surfaces for each of the ranges by subtracting each of the trajectory height surfaces for the particular range from a respective elevation surfaces; and, generate an observer view surface from the plurality of corrected elevation surfaces.