Patent Application
20150338192
The present invention is directed, in general, to weapon systems and, more specifically, to a weapon and weapon system, and methods of manufacturing and operating the same.
Present rules of engagement demand that precision guided weapons and weapon systems are necessary. According to well-documented reports, precision guided weapons have made up about 53 percent of all strike weapons employed by the United States from 1995 to 2003. The trend toward the use of precision weapons will continue. Additionally, strike weapons are used throughout a campaign, and in larger numbers than any other class of weapons. This trend will be even more pronounced as unmanned airborne vehicles (“UAVs”) take on attack roles.
Each weapon carried on a launch platform (e.g., aircraft, ship, artillery) must be tested for safety, compatibility, and effectiveness. In some cases, these qualification tests can cost more to perform than the costs of the development of the weapon system. As a result, designers often choose to be constrained by earlier qualifications. In the case of smart weapons, this qualification includes data compatibility efforts. Examples of this philosophy can be found in the air to ground munitions (“AGM”)-154 joint standoff weapon (“JSOW”), which was integrated with a number of launch platforms. In the process, a set of interfaces were developed, and a number of other systems have since been integrated which used the data sets and precedents developed by the AGM-154. Such qualifications can be very complex.
An additional example is the bomb live unit (“BLU”)-116, which is essentially identical to the BLU-109 warhead in terms of weight, center of gravity and external dimensions. However, the BLU-116 has an external “shroud” of light metal (presumably aluminum alloy or something similar) and a core of hard, heavy metal. Thus, the BLU-109 was employed to reduce qualification costs of the BLU-116.
Another means used to minimize the time and expense of weapons integration is to minimize the changes to launch platform software. As weapons have become more complex, this has proven to be difficult. As a result, the delay in operational deployment of new weapons has been measured in years, often due solely to the problem of aircraft software integration.
Some weapons such as the Paveway II laser guided bomb [also known as the guided bomb unit (“GBU”)-12] have no data or power interface to the launch platform. Clearly, it is highly desirable to minimize this form of interface and to, therefore, minimize the cost and time needed to achieve military utility.
Another general issue to consider is that low cost weapons are best designed with modularity in mind. This generally means that changes can be made to an element of the total weapon system, while retaining many existing features, again with cost and time in mind.
Another consideration is the matter of avoiding unintended damage, such as damage to non-combatants. Such damage can take many forms, including direct damage from an exploding weapon, or indirect damage. Indirect damage can be caused by a “dud” weapon going off hours or weeks after an attack, or if an enemy uses the weapon as an improvised explosive device. The damage may be inflicted on civilians or on friendly forces.
One term of reference is “danger close,” which is the term included in the method of engagement segment of a call for fire that indicates that friendly forces or non-combatants are within close proximity of the target. The close proximity distance is determined by the weapon and munition fired. In recent United States engagements, insurgent forces fighting from urban positions have been difficult to attack due to such considerations.
To avoid such damage, a number of data elements may be provided to the weapon before launch, examples of such data include information about coding on a laser designator, so the weapon will home in on the right signal. Another example is global positioning system (“GPS”) information about where the weapon should go, or areas that must be avoided. Other examples could be cited, and are familiar to those skilled in the art.
Therefore, what is needed is a small smart weapon that can be accurately guided to an intended target with the effect of destroying that target with little or no collateral damage of other nearby locations. Also, what is needed is such a weapon having many of the characteristics of prior weapons already qualified in order to substantially reduce the cost and time for effective deployment.
These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by advantageous embodiments of the present invention, which includes a weapon and weapon system, and methods of manufacturing and operating the same. In one embodiment, the weapon includes a warhead including destructive elements and a guidance section with a seeker configured to guide the weapon to a target. The seeker includes a detector configured to receive a distorted signal impinging on an objective lens from the target, memory configured to store target criteria and a correction map, and a processor configured to provide a correction signal based on the distorted signal, the target criteria and the correction map to guide the weapon to the target.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.
It should be understood that the military utility of the weapon can only be fully estimated in the context of a so-called system of systems, which includes a guidance section or system, the delivery vehicle or launch platform, and other things, in addition to the weapon per se. In this sense, a weapon system is disclosed herein, even when we are describing a weapon per se. One example is seen in the discussion of the GBU-12, wherein design choices within the weapon were reflected in the design and operation of many aircraft that followed the introduction of the GBU-12. Another example is the use of a laser designator for laser guided weapons. Design choices in the weapon can enhance or limit the utility of the designator. Other examples can be cited. Those skilled in the art will understand that the discussion of the weapon per se inherently involves a discussion of the larger weapon system of systems. Therefore, improvements within the weapon often result in corresponding changes or improvements outside the weapon, and new teachings about weapons teach about weapon platforms, and other system of systems elements.
In accordance therewith, a class of warhead assemblies, constituting systems, methods, and devices, with many features, including multiple, modular guidance subsystems, avoidance of collateral damage, unexploded ordinance, and undesirable munitions sensitivity is described herein. In an exemplary embodiment, the warheads are Mark derived (e.g., MK-76) or bomb dummy unit (“BDU”) derived (e.g., BDU-33) warheads. The MK-76 is about four inches in diameter, 24.5 inches in length, 95-100 cubic inches (“cu”) in internal volume, 25 pounds (“lbs”) and accommodates a 0.85 inch diameter practice bomb cartridge. This class of assemblies is also compatible with existing weapon envelopes of size, shape, weight, center of gravity, moment of inertia, and structural strength to avoid lengthy and expensive qualification for use with manned and unmanned platforms such as ships, helicopters, self-propelled artillery and fixed wing aircraft, thus constituting systems and methods for introducing new weapon system capabilities more quickly and at less expense. In addition, the weapon system greatly increases the number of targets that can be attacked by a single platform, whether manned or unmanned.
In an exemplary embodiment, the general system envisioned is based on existing shapes, such as the MK-76, BDU-33, or laser guided training round (“LGTR”). The resulting system can be modified by the addition or removal of various features, such as global positioning system (“GPS”) guidance, and warhead features. In addition, non-explosive warheads, such as those described in U.S. patent application Ser. No. 10/841,192 entitled “Weapon and Weapon System Employing The Same,” to Roemerman, et al., filed May 7, 2004, U.S. patent application Ser. No. 10/997,617 entitled “Weapon and Weapon System Employing the Same,” to Tepera, et al., filed Nov. 24, 2004, now U.S. Pat. No. 7,530,315, and U.S. patent application Ser. No. 11/925,471 entitled “Weapon Interface System and Delivery Platform Employing the Same,” to Roemerman, et al., filed Oct. 26, 2006, which are incorporated herein by reference, may also be employed with the weapon according to the principles of the present invention.
Another feature of the system is the use of system elements for multiple purposes. For example, the central structural element of the MK-76 embodiment includes an optics design with a primary optical element, which is formed in the mechanical structure rather than as a separate component. Another example is the use of an antenna for both radio guidance purposes, such as GPS, and for handoff communication by means such as those typical of a radio frequency identification (“RFID”) system. For examples of RFID related systems, see U.S. patent application Ser. No. 11/501,348, entitled “Radio Frequency Identification Interrogation Systems and Methods of Operating the Same,” to Roemerman, et al., filed Aug. 9, 2006, now U.S. Patent Application Publication No. 2007/0035383, U.S. Pat. No. 7,019,650 entitled “Interrogator and Interrogation System Employing the Same,” to Volpi, et al., issued on Mar. 28, 2006, U.S. Patent Application Publication No. 2006/0077036, entitled “Interrogation System Employing Prior Knowledge About An Object To Discern An Identity Thereof,” to Roemerman, et al., filed Sep. 29, 2005, U.S. Patent Application Publication No. 2006/0017545, entitled “Radio Frequency Identification Interrogation Systems and Methods of Operating the Same,” to Volpi, et al., filed Mar. 25, 2005, U.S. Patent Application Publication No. 2005/0201450, entitled “Interrogator And Interrogation System Employing The Same,” to Volpi, et al., filed Mar. 3, 2005, all of which are incorporated herein by reference.
Referring now to
The weapon system is configured to provide energy as derived, without limitation, from a velocity and altitude of the delivery vehicle 110 in the form of kinetic energy (“KE”) and potential energy to the first and second weapons 120, 130 and, ultimately, the warhead and destructive elements therein. The first and second weapons 120, 130 when released from the delivery vehicle 110 provide guided motion for the warhead to the target. The energy transferred from the delivery vehicle 110 as well as any additional energy acquired through the first and second weapons 120, 130 through propulsion, gravity or other parameters, provides the kinetic energy to the warhead to perform the intended mission. While the first and second weapons 120, 130 described with respect to
In general, it should be understood that other delivery vehicles including other aircraft may be employed such that the weapons contain significant energy represented as kinetic energy plus potential energy. As mentioned above, the kinetic energy is equal to “½ mv2,” and the potential energy is equal to “mgh” where “m” is the mass of the weapon, “g” is gravitational acceleration equal to 9.8 M/sec2, and “h” is the height of the weapon at its highest point with respect to the height of the target. Thus, at the time of impact, the energy of the weapon is kinetic energy, which is directed into and towards the destruction of the target with little to no collateral damage of surroundings. Additionally, the collateral damage may be further reduced if the warhead is void of an explosive charge.
Turning now to
Turning now to
The guidance section 310 may include components and subsystems such as a GPS, an antenna such as a ring antenna 330 (e.g., dual use handoff and data and mission insertion similar to radio frequency identification and potentially also including responses from the weapon via similar means), a multiple axis microelectomechanical gyroscope, safety and arming devices, fuzing components, a quad detector, a communication interface [e.g., digital subscriber line (“DSL”)], and provide features such as low power warming for fast acquisition and inductive handoff with a personal information manager. In the illustrated embodiment, the antenna 330 is about a surface of the weapon. Thus, the antenna is configured to receive mission data such as location, laser codes, GPS ephemerides and the like before launching from a delivery vehicle to guide the weapon to a target. The antenna is also configured to receive instructions after launching from the delivery vehicle to guide the weapon to the target. The weapon system, therefore, includes a communication system, typically within the delivery vehicle, to communicate with the weapon, and to achieve other goals and ends in the context of weapon system operation. It should be understood that the guidance section 310 contemplates, without limitation, laser guided, GPS guided, and dual mode laser and GPS guided systems. It should be understood that this antenna may be configured to receive various kinds of electromagnetic energy, just as there are many types of RFID tags that are configured to receive various kinds of electromagnetic energy.
The weapon also includes a warhead 340 (e.g., a unitary configuration) having destructive elements (formed from explosive or non-explosive materials), mechanisms and elements to articulate aerodynamic surfaces. A folding lug switch assembly 350, safety pin 360 and cavity 370 are also coupled to the guidance section 310 and the warhead 340. The guidance section 310 is in front of the warhead 340. The folding lug switch assembly 350 projects from a surface of the weapon. The weapon still further includes an aft section 380 behind the warhead 340 including system power elements, a ballast, actuators, flight control elements, and tail fins 390.
For instances when the target sensor is a laser seeker, the laser seeker detects the reflected energy from a selected target which is being illuminated by a laser. The laser seeker provides signals so as to drive the control surfaces in a manner such that the weapon is directed to the target. The tail fins 390 provide both stability and lift to the weapon. Modern precision guided weapons can be precisely guided to a specific target so that considerable explosive energy is often not needed to destroy an intended target. In many instances, kinetic energy discussed herein may be sufficient to destroy a target, especially when the weapon can be directed with sufficient accuracy to strike a specific designated target.
The destructive elements of the warhead 340 may be constructed of non-explosive materials and selected to achieve penetration, fragmentation, or incendiary effects. The destructive elements (e.g., shot) may include an incendiary material such as a pyrophoric material (e.g., zirconium) therein. The term “shot” generally refers a solid or hollow spherical, cubic, or other suitably shaped element constructed of explosive or non-explosive materials, without the aerodynamic characteristics generally associated with, for instance, a “dart.” The shot may include an incendiary material such as a pyrophoric material (e.g., zirconium) therein. Inasmuch as the destructive elements of the warhead are a significant part of the weapon, the placement of these destructive elements, in order to achieve the overall weight and center of gravity desired, is an important element in the design of the weapon.
The non-explosive materials applied herein are substantially inert in environments that are normal and under benign conditions. Nominally stressing environments such as experienced in normal handling are generally insufficient to cause the selected materials (e.g., tungsten, hardened steel, zirconium, copper, depleted uranium and other like materials) to become destructive in an explosive or incendiary manner. The latent lethal explosive factor is minimal or non-existent. Reactive conditions are predicated on the application of high kinetic energy transfer, a predominantly physical reaction, and not on explosive effects, a predominantly chemical reaction.
The folding lug switch assembly 350 is typically spring-loaded to fold down upon release from, without limitation, a rack on an aircraft. The folding lug switch assembly 350 permits initialization after launch (no need to fire thermal batteries or use other power until the bomb is away) and provides a positive signal for a fuze. The folding lug switch assembly 350 is consistent with the laser guided bomb (“LGB”) strategy using lanyards, but without the logistics issues of lanyards. The folding lug switch assembly 350 also makes an aircraft data and power interface optional and supports a visible “remove before flight” pin. The folding lug switch assembly 350 provides a mechanism to attach the weapon to a delivery vehicle and is configured to close after launching from the delivery vehicle thereby satisfying a criterion to arm the warhead. It should be understood, however, that the folding lug switch assembly 350, which is highly desirable in some circumstances, can be replaced with other means of carriage and suspension, and is only one of many features of the present invention, which can be applied in different combinations to achieve the benefits of the weapon system.
Typically, the safety pin 360 is removed from the folding lug switch assembly 350 and the folding lug switch assembly 350 is attached to a rack of an aircraft to hold the folding lug switch assembly 350 in an open position prior to launch. Thus, the safety pin 360 provides a mechanism to arm the weapon. Once the weapon is launched from the aircraft, the folding lug switch assembly 350 folds down into the cavity 370 and provides another mechanism to arm the weapon. A delay circuit between the folding lug switch assembly 350 and the fuze may be yet another mechanism to arm or provide time to disable the weapon after launch. Therefore, there are often three mechanisms that are satisfied before the weapon is ultimately armed enroute to the target.
A number of circuits are now well understood that use power from radio frequency or inductive fields to power a receiving chip and store data. The antenna includes an interface to terminate with the aircraft interface at the rack for loading relevant mission data including target, location, laser codes, GPS ephemerides and the like before being launched. Programming may be accomplished by a hand-held device similar to a fuze setter or can be programmed by a lower power interface between a rack and the weapon. Other embodiments are clearly possible to those skilled in the art. The antenna serves a dual purpose for handoff and GPS. In other words, the antenna is configured to receive instructions after launching from the delivery vehicle to guide the weapon to the target. Typically, power to the weapon is not required prior to launch, therefore no umbilical cable is needed. Alternative embodiments for power to GPS prior to launch are also contemplated herein.
The modular design of the weapon allows the introduction of features such as GPS and other sensors as well. Also, the use of a modular warhead 340 with heavy metal ballast makes the low cost kinetic [no high explosives (“HE”)] design option practical and affordable.
As illustrated in an exemplary embodiment of a weapon in the TABLE 1 below, the weapon may be designed to have a similar envelope, mass, and center of gravity already present in existing aircraft for a practice bomb version thereof. Alternatively, the weapon may be designed with other envelopes, masses, and centers of gravity, as may be available with other configurations, as also being included within the constructs of this invention.
In the above example, the weapon is MK-76 derived, but others such as BDU-33 are well within the broad scope of the present invention. The weapon provides for very low cost of aircraft integration. The warhead 340 is large enough for useful warheads and small enough for very high carriage density. The modular design of the weapon allows many variants and is compatible with existing handling and loading methods.
The following TABLEs 2 and 3 provide a comparison of several weapons to accentuate the advantages of small smart weapons such as the MK-76 and BDU-33.
The aforementioned tables provide a snapshot of the advantages associated with small smart weapons, such as, procurements are inevitable, and the current weapons have limited utility due to political, tactical, and legal considerations. Additionally, the technology is ready with much of it being commercial off-the-shelf technology and the trends reflect these changes. The smart weapons are now core doctrine and contractors can expect production in very large numbers. Compared to existing systems, small smart weapons exhibit smaller size, lower cost, equally high or better accuracy, short time to market, and ease of integration with an airframe, which are key elements directly addressed by the weapon disclosed herein. As an example, the small smart weapon could increase an unmanned combat air vehicle (“UCAV”) weapon count by a factor of two or more over a small diameter bomb (“SDB”) such as a GBU-39/B.
The small smart weapons also address concerns with submunitions, which are claimed by some nations to fall under the land mine treaty. The submunitions are a major source of unexploded ordnance, causing significant limitations to force maneuvers, and casualties to civilians and blue forces. Submunitions are currently the only practical way to attack area targets, such as staging areas, barracks complexes, freight yards, etc. Unexploded ordnance from larger warheads are a primary source of explosives for improvised explosive devices. While the broad scope of the present invention is not so limited, small smart weapons including small warheads, individually targeted, alleviate or greatly reduce these concerns.
Turning now to
In an exemplary embodiment, a sensor of the weapon detects a target in accordance with, for instance, pre-programmed knowledge-based data sets, target information, weapon information, warhead characteristics, safe and arm events, fuzing logic and environmental information. In the target region, sensors and devices detect the target and non-target locations and positions. Command signals including data, instructions, and information contained in the weapon (e.g., a control section) are passed to the warhead. The data, instructions, and information contain that knowledge which incorporates the functional mode of the warhead such as safe and arming conditions, fuzing logic, deployment mode and functioning requirements.
The set of information as described above is passed to, for instance, an event sequencer of the warhead. In accordance therewith, the warhead characteristics, safe and arm events, fuzing logic, and deployment modes are established and executed therewith. At an instant that all conditions are properly satisfied (e.g., a folding lug switch assembly is closed), the event sequencer passes the proper signals to initiate a fire signal to fuzes for the warhead. In accordance herewith, a functional mode for the warhead is provided including range characteristics and the like. Thereafter, the warhead is guided to the target employing the guidance section employing, without limitation, an antenna and global positioning system.
Thus, a class of warhead assemblies, constituting systems, methods, and devices, with many features, including multiple, modular guidance subsystems, avoidance of collateral damage, unexploded ordinance, and undesirable munitions sensitivity has been described herein. The weapon according to the principles of the present invention provides a class of warheads that are compatible with existing weapon envelopes of size, shape, weight, center of gravity, moment of inertia, and structural strength, to avoid lengthy and expensive qualification for use with manned and unmanned platforms such as ships, helicopters, self-propelled artillery and fixed wing aircraft, thus constituting systems and methods for introducing new weapon system capabilities more quickly and at less expense. In addition, the weapon system greatly increases the number of targets that can be attacked by a single platform, whether manned or unmanned.
Turning now to
Referring once more to the target sensor discussed above, a semi-active laser (“SAL”) seeker is typically the most complex item in SAL guided systems, and SAL is the most commonly used means of guiding precision weapons. Therefore, a low cost and compact approach, consistent with a very confined space, is highly desirable.
Turning now to
EL=((A+B)−(C+D))/(A+B+C+D), and
AZ=((A+D)−(B+C))/(A+B+C+D).
A reflected spot from a laser 605 is shown in quadrant B where the spot is focused on the plane of the active detecting area.
Turning now to
Turning now to
Turning now to
An alternative embodiment that specifically addresses the focus errors discussed above for a FFL is to add lens stopping (i.e., optical barriers) in those regions where unwanted energy is most likely to originate. This slightly reduces the amount of light passed on by the lens, but also significantly reduces the focusing error for a net gain in performance.
Yet another embodiment of this invention is to replace the concentric circles of the FFL with randomized circles as illustrated in
Turning now to
Therefore, by placing a small amount of optical focusing power in the front lens 925, the focal length of the FFL 930 is allowed to be longer, making it easier to manufacture, while the optical system of
Turning now to
Turning now to
Turning now to
Turning now to
Yet another embodiment of variable aspect ratio is also comprehended by this invention wherein the tail fin dimensions may not change in flight. Referring now to
In accordance with a guidance section, a target sensor (also referred to as a seeker such as a laser seeker) detects energy that provides directional information to guide a weapon to a target. The seekers may be “active” emitting energy as in the case of radar, “passive” as in the case of a weapon using a television image based on natural illumination, or “semi-active” as in the case of laser guided bombs, wherein a laser spot designates the target. The weapon as described herein may employ active, passive or semi-active seekers. Additionally, the seeker as described herein takes into account arbitrary aerodynamic shapes without compromising the optical objective apertures and is consistent with the ongoing pressures for reduced cost, weight and volume.
Guided weapons were first used in World War II and, late in the war, Germany, the United States and others were developing and deploying the first guided weapons with “terminal guidance” or a “seeker” to attack moving targets, or to arrive at an aim point with a small miss distance. These early systems, such as the German “Fritz-X” and the allied special weapons ordnance device (“SWOD”) MK-9/air-to-surface missile (“ASM”)-N-2 “BAT” are recognizable as guided weapons with functional block diagrams similar to those in service today.
However, the size and weight of the elements is remarkably different. The BAT is considered by many historians to be the first true fire and forget guided weapon with a seeker unaided by an operator and data link. The BAT is exemplary of seeker trends and challenges. The BAT weighed roughly 1000 kilograms (“kg”) and had a wingspan of about 3 meters. Roughly 40% of the weight of the system was not the warhead. The BAT used three large lead acid batteries as a power source. These were much larger than the batteries commonly found in automobiles today, so just the power source for BAT was larger than some modern guided weapons such as the TOW or Javelin (Javelin weighs less than 30 kg).
The components of guided weapons have seen remarkable reduction in size and cost. The Javelin, with a warhead weight of less than 10 kg can penetrate more than half a meter of armor, a feat that would have required a warhead mass at least ten times greater in 1950. The signal processing electronics in the BAT relied on less than 20 vacuum tubes. Each tube was roughly a thousand times larger and used roughly a thousand times more power than one modern digital signal processor (“DSP”). So, components other than the seeker have seen four orders of magnitude, or more reduction in size and, in many cases, the costs have fallen dramatically as well.
Thus, the state of the art seekers' performance can be changed in response to modern objectives. In particular, the need to package seekers based on demands of airframes' allowance for weight (e.g., less than 1 kg), volume (e.g., less than 0.1 liters) and outer mold line have become quite challenging. In the past, the leading edge of the weapon was generally a compromise between airframe needs and the design constraints of the seeker. For instance, the flight and guidance times have been reduced from a minute to 10 seconds and the accuracy is critical to the reduction of warhead size and collateral damage. The seeker as described herein eliminates many of the past compromises.
Semi active laser (“SAL”) seekers are among the simplest of weapon guidance devices. SAL seekers employ parabolic optical lenses and limited integration (e.g., Hellfire has electronic counter-countermeasures (“ECCM”) in a separate chip and Paveway III has gyros on its gimbals as well as body fixed gyros). Also, the SAL seekers employ functional separation such as sensor stabilization separate from line-of-sight (“LOS”) estimation and error correction (if any) is performed by additional optical elements (see, e.g., U.S. Patent Application No. 2007/0187546 entitled “Binary Optics SAL Seeker (BOSS),” to Layton, published Aug. 16, 2007, which is incorporated herein by reference. Generally, such seekers operate at only one or two optical wavelengths, and have detectors with as few as four elements. They are found in the least expensive guided weapons, such as laser guided bombs. While these systems have provided much of the stimulus for low cost, they have also continued to demonstrate many of the compromises discussed previously. Similar examples can be given for other classes of seekers. However, since even the most basic seekers demonstrate these undesirable attributes, it will be apparent to those skilled in the art that more sophisticated seekers also manifest these attributes.
Turning now to
While the bodies presented may be well defined by algebraic equations, the considerations that determine these shapes is aerodynamic, and the effect of the shape on electromagnetic energy, that may need to pass through a transparent window in the nose or forepart, is often not a consideration. The shape of these bodies has been a challenge for seeker designers, and a number of compromises have been required to deal with the challenges. Some of the compromises are unsatisfactory and create significant system costs in terms of price, weight, performance, or other costs. Moreover, theoretical shapes are idealized representations of systems that can be practically realized. For this reason, these shapes are sometimes called ogvial, or near ogive.
An arc of rotation is often used to describe an ogive. A formula is useful for modern machining and analysis methods. The formula for a tangent ogive is shown below, wherein x, y are coordinates, x being along the length of the cone, and y being the height (or radius) of the cone taken from the centerline of the cone.
The caliber of the cone is C=L/d, wherein L is the cone length and d is the cone base diameter.
A number of practical factors should be considered in the design of a nose shape. Examples of nose shapes include bi-conic, spherically blunted cones, spherically blunted ogives, HAACK, elliptical ogives, parabolic (which generally has a sharp tip similar to a tangent ogive), and so called power series (which often produces the best result in terms of drag). Some of these shapes are more practical than others. In addition, mission requirements such as the need for a fuzing crush switch (e.g., for contact fuzing) on or near the nose, or the need to provide for penetration kinematics can also be factors in the final design. So, it should be clear that a wide range of factors (aerodynamics, manufacturing processes, environmental demands, fuzing, penetration) should come to bear in the selection of the nose shape of a guided missile, and that optical (or antenna) issues cannot be the sole design criteria for selecting the shape, material and other nose features. Those skilled in the art will recognize that the factors described here are exemplary and not an exhaustive list. Clearly, a seeker approach that accommodated non-optical (or antenna) concerns would be very useful.
Turning now to
As illustrated in
In contrast, target C is not inverted by the nose cone, but because the geometry of the regions presents different angles of incidence to incoming rays, the resulting dashed arrow associated with target C is bent or distorted. As the maneuverability of guided weapons has increased, the importance of these considerations has increased because of the need to achieve high angles of attack, and to attack targets far from bore sight. If a ray is traced for target B, it would be influenced by all three regions. Note that significant errors have been introduced before an objective lens 1650. The optical train that begins with the objective lens 1650 and ends with a sensor of some type, will also have limitations such as imperfect collimation. As errors propagate and compound, it can be difficult or even impossible to generate useful guidance signals.
It is clear to those skilled in the art that complex nose shapes and large line-of-sight angles pose a challenge to the seeker designer. Further, the need to provide for a very large window, forward of an opaque region 1660 can be quite costly and in some applications materials with the right combination of thermal, optical, and structural characteristics can cause the dome to be the most expensive component in the seeker, if the design can be realized at all.
Turning now to
Note that the primary optical aperture (primary mirror 1750) is smaller than the dome 1710. In this case, the primary minor 1750 is set by the need for optical gain, and a fast f-number. The dome size, however, is set by the need to point the primary minor 1750 toward the target because the instantaneous field of view is too small to engage all of the needed target geometries. The dome size is also influenced by the dimensions of the telescope assembly and of the gimbal set. If a smaller telescope with a large instantaneous field of view is used, the seeker could be designed with less complexity and cost.
Thus, advantageous characteristics of seekers include a small diameter objective to permit placement as far forward as possible in the warhead and support for line-of-sight angles. Additionally, seekers should support nose shapes determined by aerodynamics, material properties, manufacturing tolerances and cost. Seekers should also employ simple means to correct for optical errors with the need to accommodate multi-mode sensors operating at different wavelengths. It would also be beneficial to avoid complexity and high component counts to include a low number of optical components, no gimbals, simple collimation and simple assembly.
Turning now to
In
Those skilled in the art of optics design will recognize the rough approximation of a classic “fish eye” objective, with a wide field of view, but will also recognize that in addition to typical fish eye distortion, additional distortion has been created by the flattened front surface, and by the practical limits of correction of the back surface. The classic optics approach to solving these problems would be to add additional glass types, creating a doublet or triplet, to add additional elements (either lens or corrective holograms), or some combination of these features. An example of such multi-element approach can be found in Layton introduced above.
Clearly, this approach is much less complex and, therefore, less expensive. For the SAL seeker, it is likely that the objective lens could be cast from a material such as Pyrex and would not need additional polishing, since the seeker does not require sharp focus. This aspect of the seeker, however, taken alone may not provide adequate guidance accuracy for some applications.
Turning now to
In the illustrated embodiment, the illumination (depicted by the dashed arrow) is 60 degrees off bore sight. By illuminating the seeker from a plurality of locations across the calibration array 1920, a seeker response map can be constructed. By comparing the seeker response map with the known angles of illumination, a seeker correction map can be constructed that render less complex and inexpensive weapons comparable in performance to weapons of higher complexity and cost.
For some sensor types, nonlinear response will dictate that a plurality of maps be constructed to accommodate illumination polarization, intensity and other characteristics. The details of the mapping strategy is dictated by the characteristics of the detector, and of the type of electromagnetic energy detected. However, the primary requirement for the calibration system to provide a useful seeker response map is that the transfer function provided by the optical system from incoming illumination to electrical output be a one-to-one manifold.
Turning now to
The objective lens is positioned relative to a detector 2040 by a standoff (e.g., a standoff tube) 2030. The detector is illuminated by the energy focused by the objective lens, creating a signal sent to the amplifier and analog-to-digital converter (“ADC”) 2050. A processor 2060 in connection with memory 2070 uses specified target criteria (for example, laser pulse to pulse interval) to determine if incoming signals are from a valid target, and uses the correction map to provide a more accurate line-of-sight estimate (i.e., output data including a correction signal to guide a weapon employing the seeker to the target).
The construction of the system shown here will vary with a number factors. For example, subsonic flight permits a wider range of optical materials and nose shapes than transonic or supersonic flight. The detector 2040, objective lens, standoff 2030 and processor 2060 may be manufactured as single unit, so that errors in collimation are included in the correction map, thus lowering the cost and required precision of assembly. In this way, the correction map is integral to the seeker head assembly reducing the chance that a correction map will be associated with the wrong seeker assembly.
The processor 2060 may be of any type suitable to the local application environment, and may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (“DSPs”), field-programmable gate arrays (“FPGAs”), application-specific integrated circuits (“ASICs”), and processors based on a multi-core processor architecture, as non-limiting examples. The memory 2070 may also include one or more memories of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and removable memory. The programs stored in the memory may include program instructions or computer program code that, when executed by an associated processor, enable the seeker to perform tasks as described herein.
Thus, the ones of the modules of the seeker may be implemented in accordance with hardware (embodied in one or more chips including an integrated circuit such as an application specific integrated circuit), or may be implemented as software or firmware for execution by a processor. In particular, in the case of firmware or software, the exemplary embodiment can be provided as a computer program product including a computer readable medium or storage structure embodying computer program code (i.e., software or firmware) thereon for execution by the processor.
Furthermore, the seeker as disclosed herein permits very simple optical tube designs, which can be held in place by means of simple compression and fasteners, avoiding complex optical assemblies or exotic optical adhesives. Embodiments for high mach regimes will vary and may require thermal isolation for the detector 2040 and processing electronics. The seeker typically includes other modules such as a filter to block energy outside the desired band associated with the target designator. In the exemplary embodiment, the filter may include coatings deposited on the back surface 2020 of the objective lens.
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As mentioned previously, warheads are increasingly being used near sensitive population and structures wherein the distance between hostile and engaged troops is often less than 200 meters in urban operations and the hazard distance for a typical air delivered munition is more than 200 meters. While some low yield warheads have been successfully demonstrated (e.g., BLU-126, which is partially filled with inert fill before adding the explosive and is a variant of MK-82), there is still a lack of ability to select the level of output or variability once a mission has begun. It would be beneficial to employ a weapon that can provide full warhead output, or can be selectively reduced based on rules of engagement.
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Regarding
It should be understood that a very fast linear burn rate of the SLSCJ can be difficult to precisely control in some circumstances. One means of achieving better control, and for some warhead shapes, better controlling hazardous fragmentation (e.g., case fragment size), is to use the variable wrap. Again, the variability may be employed across the length of the warhead, as shown in this figure, or may vary with shape for non-cylindrical warheads. In a related embodiment, different size cutter charges may be employed to accommodate variable warhead case thickness, or fill diameter. When multiple cutter sizes are used, the linear burn rate of the cutter can be affected by cutter size, and variable wrap rate is a means to compensate for these changes.
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Although the integrated assembly is called a liner or case liner, it is not limited to a conventional liner, conformal to the inner diameter of a warhead case. Other exemplary embodiments include instances wherein the integrated assembly could be installed outside the warhead case, or as a sub-diameter assembly coaxial to the warhead case, or in other configurations. It should be clear to those skilled in the art that the mandrel is one desirable means to form the integrated assembly though not absolutely necessary to achieve the desired effects
As illustrated in
Additionally, exemplary embodiments of the present invention have been illustrated with reference to specific components. Those skilled in the art are aware, however, that components may be substituted (not necessarily with components of the same type) to create desired conditions or accomplish desired results. For instance, multiple components may be substituted for a single component and vice-versa. The principles of the present invention may be applied to a wide variety of weapon systems. Those skilled in the art will recognize that other embodiments of the invention can be incorporated into a weapon that operates on the principle of lateral ejection of a warhead or portions thereof. Absence of a discussion of specific applications employing principles of lateral ejection of the warhead does not preclude that application from failing within the broad scope of the present invention.
Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This application is a Continuation of U.S. patent application Ser. No. 14/30,254 entitled “Small Smart Weapon and Weapon System Employing the Same,” filed Sep. 18, 2013, currently allowed, which is a division application of U.S. patent application Ser. No. 12/850,421 entitled “Small Smart Weapon and Weapon System Employing the Same,” filed Aug. 4, 2010, will issue as U.S. Pat. No. 8,541,724 on Sep. 24, 2013, which is a continuation-in-part of U.S. patent application Ser. No. 11/706,489 entitled “Small Smart Weapon and Weapon System Employing the Same,” filed Feb. 15, 2007, now U.S. Pat. No. 7,895,946, which is a continuation-in-part of U.S. patent application Ser. No. 11/541,207 entitled “Small Smart Weapon and Weapon System Employing the Same,” filed Sep. 29, 2006, now U.S. Pat. No. 7,690,304, and also claims the benefit of U.S. Provisional Application No. 61/231,141 entitled “Novel Body Fixed Seekers and Variable Output Explosive Devices,” filed Aug. 4, 2009, which applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61231141 | Aug 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12850421 | Aug 2010 | US |
| Child | 14030254 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14030254 | Sep 2013 | US |
| Child | 14747152 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11706489 | Feb 2007 | US |
| Child | 12850421 | US | |
| Parent | 11541207 | Sep 2006 | US |
| Child | 11706489 | US |
