Guided munitions including self-deploying dome covers and methods for equipping guided munitions with the same

Embodiments of a guided munition are provided, as are embodiments of a method for equipping a guided munition with a self-deploying dome cover. In one embodiment, the guided munition includes a munition body, a seeker dome coupled to the munition body, and a self-deploying dome cover disposed over the seeker dome. The self-deploying dome cover is configured to deploy and expose the seeker dome during munition flight in response to aerodynamic forces acting on the self-deploying dome cover.

TECHNICAL FIELD

The following disclosure relates generally to guided munitions and, more particularly, to embodiments of guided munitions including self-deploying dome covers.

BACKGROUND

Demands for increased munition portability, versatility, and ruggedness have lead to the recent development and implementation of containerized guided missiles, which are stowed within specialized launch containers prior to launch. As do non-containerized guided missiles, containerized guided missiles typically include a homing guidance system or “seeker” containing one or more electromagnetic (“EM”) radiation sensors, which detect electromagnetic radiation emitted by or reflected from a designated target. A containerized guided missile also typically includes a nose-mounted seeker dome, which protects the seeker's components while enabling transmission of electromagnetic waves within the sensor bandwidth(s) through the dome and to the seeker's EM radiation sensors.

In contrast to many conventional guided missiles, containerized guided missiles are prone to dome contamination during missile launch. Guided by the walls of the surrounding launch container, exhaust from the missile's rocket motor flows over and around the missile body in an aft-fore direction during missile launch to blow-off the container cover and thereby facilitate passage of the missile through the container's open end. Direct exposure between the motor exhaust and seeker dome can thus occur during missile launch, which may result in the deposition of harsh chemicals, soot, and other exhaust materials over the dome's outer surface. Dome contamination can block, attenuate, or otherwise interfere with the transmission of electromagnetic signals through the dome and thereby negatively impact the missile's guidance capabilities.

It is known that a dome cover can be positioned over a missile dome to minimize or prevent dome contamination during missile launch. However, inflight removal of the dome cover is required to enable subsequent operation of the seeker's EM radiation sensors. Various types of deployment systems (e.g., actuators and timing electronics) have been developed that can effectively remove a dome cover by either ejecting the cover (if fabricated from a non-frangible material) or by initiating fracture of the cover (if fabricated from a frangible material) during or immediately after missile launch. While able to effectively remove a dome cover at a desired time of deployment, such deployment systems add undesirable complexity, cost, bulk, and weight to the guided missile. Tether-pull dome cover systems have been suggested that do not require an actuator or timing electronics; however, a relatively lengthy tether is typically required to ensure that the dome cover is not removed until the missile has cleared any forward-expanding exhaust plume created during missile launch. Consequently, tether-pull dome cover systems also tend to be undesirably heavy and bulky. In addition, tether-pull dome cover systems and certain non-frangible, actuator-deployed dome covers can produce undesirably large, high-energy debris upon dome deployment.

There thus exists an ongoing need to provide embodiments of a guided munition including a dome cover that mitigates most, if not all, of the above-described limitations. In particular, it would be desirable to provide embodiments of a guided munition, such as a containerized guided munition, including a dome cover that reliably self-deploys at a desired time without the aid of an actuator, timing electronics, or similar devices. Ideally, such a self-deploying dome cover would also be relatively compact, inexpensive to implement, and would produce little to no high-energy debris upon deployment. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and this Background.

BRIEF SUMMARY

Embodiments of a guided munition are provided. In one embodiment, the guided munition includes a munition body, a seeker dome coupled to the munition body, and a self-deploying dome cover disposed over the seeker dome. The self-deploying dome cover is configured to deploy and expose the seeker dome during munition flight in response to aerodynamic forces acting on the self-deploying dome cover.

Embodiments of a method for equipping a guided munition including a seeker dome with a self-deploying dome cover are also provided. In one embodiment, the method includes the steps of providing a self-deploying dome cover configured to open during munition flight in response to aerodynamic forces acting on the self-deploying dome cover when the guided munition surpasses a predetermined airspeed, positioning the self-deploying dome cover over the seeker dome, and stowing the guided munition within a launch container.

DETAILED DESCRIPTION

FIG. 1is a cutaway view of an All-Up-Round (“AUR”)10including a guided munition12stowed within a launch container14and illustrated in accordance with an exemplary embodiment. In this particular example, guided munition12assumes the form of a missile, such as a precision or loitering attack missile. AUR10can be implemented as a standalone launch unit or may instead be packaged with other All-Up-Rounds in, for example, a palletized launch system. As a specific example, AUR10may be one of several All-Up-Rounds packaged within a Container Launch Unit (commonly referred to by the acronym “CLU”) included within a Non-Line of Sight Launch System (commonly referred to by the acronym “NLOS-LS”). The foregoing examples notwithstanding, embodiments of the self-deploying dome cover described herein are by no means limited to usage in conjunction within a particular type of launch system or in conjunction with a particular type of guided munition. Instead, embodiments of the self-deploying dome cover can be utilized in conjunction with any type of guided munition that includes a seeker dome transmissive to EM radiation or EM signals of the type described herein, whether or not the guided munition is containerized. Embodiments of the self-deploying dome cover are especially well-suited for utilization in conjunction with guided munitions that are containerized (i.e., initially stowed within a launch tube or other container) or otherwise shielded from significant fore-aft airflow prior to munition launch.

With continued reference toFIG. 1, guided munition12includes a munition body16, a seeker dome18coupled or mounted to the forward end of munition body16, and a homing guidance system or seeker19housed within a forward section of munition body16. Seeker19, in turn, includes one or more electromagnetic (“EM”) radiation sensors22positioned within or adjacent to seeker dome18; e.g., in one common implementation, sensors22are carried by a gimbal assembly (not shown) partially disposed within dome18. During seeker operation or imaging, EM radiation sensors22detect electromagnetic radiation emitted by or reflected from a designated target or targets and transmitted through dome18. Although not shown inFIG. 1for clarity, seeker19will include a number of other conventionally-known components suitable for providing the desired homing functionalities. Such components may include, but are not limited to, guidance control electronics (e.g., a control card stack), antennae, internal navigational systems (e.g., global positioning systems and/or inertial navigational systems), power supplies (e.g., battery packs), and the like. Seeker19may also include a data link (e.g., a networked radio antenna) to enable the transmission of in-flight targeting updates and imaging data. More generally, guided munition12will likewise include various components that are conventionally-known in the aerospace or munition industry and not described in detail herein. Such components may include, but are not limited to, a plurality of manipulable flight control surfaces (e.g., wings24and thrust vector control vanes26, as described more fully below), one or more warheads (not shown), and one or more propulsion devices, such as a solid propellant rocket motor (generically represented inFIG. 1by box28).

As previously indicated, seeker dome18is transmissive to one or more bandwidths of electromagnetic radiation emitted by or reflected from a designated target and detectable by EM radiation sensors22. Seeker dome18will typically be transmissive to one or more of the visible, near infrared, midwave infrared, long wave infrared, and/or millimeter-wave radio frequency bandwidths. Seeker dome18can be formed from any material, currently known or later developed, that allows the transmission of EM radiation or signals through dome18within the desired sensor bandwidth(s) and that possesses sufficient structural strength to remain intact during munition handling, launch, and flight. By way of non-limiting example, seeker dome18may be formed from diamond, sapphire, zinc sulfide (ZnS), yttrium oxide (Y2O3) aluminum oxynitride (AlON), Spinel (MgAl2O4), magnesium fluoride (MgF2), composite optical ceramics, and similar materials. Although by no means limited to a particular geometry, seeker dome18will typically be either hemispherical or ogival in shape.

EM radiation sensors22are configured to receive electromagnetic radiation through seeker dome18emitted from or from a designated target to provide passive guidance, semi-active guidance, or active guidance in the conventionally-known manner. EM radiation sensors22may comprise any number of electromagnetic radiation detection devices suitable for performing this purpose and for detecting radiation within any given frequency band of the electromagnetic spectrum including, but not limited to, one or more of the ultraviolet, visible, infrared (e.g., near-infrared, mid-infrared, and far-infrared), microwave, and radio wave frequencies. As a non-exhaustive list of examples, EM radiation sensors22may include one or more visible spectrum, semi-active laser, infrared, and/or millimeter wave detection devices. In the illustrated exemplary embodiment wherein guided munition12assumes the form of a precision attack missile, EM radiation sensors22conveniently include an uncooled imaging infrared sensor and a semi-active laser sensor. In another embodiment wherein guided munition12assumes the form of a loitering attack missile, EM radiation sensors22may comprise one or more laser radar sensors.

As noted above, guided munition12further includes a plurality of deployable flight control surfaces, which can be manipulated during munition flight by non-illustrated actuation means to provide aerodynamic guidance of guided munition12in accordance with homing data or command signals provided by seeker19. In the illustrated example, specifically, guided munition12includes a plurality of wings24and a plurality of thrust vector control (“TVC”) vanes26, which are circumferential spaced around intermediate and aft portions of munition body16, respectively. To facilitate storage within launch container14, wings24and TVC vanes26are mounted to munition body16so as to be movable between a stowed or collapsed position (shown inFIG. 1) and a deployed position (shown inFIGS. 4 and 5, described below).

Launch container14can assume any form suitable for accommodating guided munition12prior to munition launch. In the exemplary embodiment illustrated inFIG. 1, launch container14assumes the form of an elongated launch tube including a closed end30and an open end32. A container cover34is disposed over open end32to enclose launch container14and thereby protect munition12prior to munition launch. To initiate munition launch, rocket motor28is activated (e.g., via ignition of a non-illustrated ignition charge) to generate exhaust gases, which exit munition body16through a rocket nozzle (not shown) and provide forward thrust to munition12. Guided by the walls of launch container14, the exhaust gases flow over and around guided munition12in an aft-fore direction (i.e., upward in the illustrated orientation) to exert pressure on the inner face of container cover34. When the pressure exerted on cover34surpasses a certain threshold, container cover34is effectively displaced from or blown-off of launch container14thereby facilitating the passage of guided munition12through open end32. The forward end of guided munition12remains enveloped by rocket motor exhaust for a short distance of travel, typically equivalent to approximately one missile length, as the motor exhaust flowing through open end32forms a forward-expanding exhaust plume. Self-deploying dome cover20overlays or encloses seeker dome18to prevent contamination of dome18by the surrounding motor exhaust during the launch sequence and munition fly-out. However, shortly after munition launch, and specifically when guided munition12surpasses a predetermined positive airspeed, dome cover20self-deploys to expose the underlying seeker dome18and allow operation of EM radiation sensors22and, more generally, of seeker19. The manner in which dome cover20is able to self-deploy at a predetermined juncture during munition flight without the aid of external devices (e.g., an actuator or timing electronics) is described more fully below in conjunction withFIGS. 2-5.

FIGS. 2 and 3are isometric views of self-deploying dome cover20prior to and after deployment, respectively. Self-deploying dome cover20resides in the closed position shown inFIG. 2wherein dome cover20overlays or encloses seeker dome18to prevent contamination of dome18prior to and during the initial stages of munition launch. Self-deploying dome cover20is configured to move into the open position (FIG. 3) during munition flight in response to aerodynamic forces acting on cover20when guided munition12(FIG. 1) surpasses a predetermined positive airspeed. In the illustrated example, specifically, self-deploying dome cover20includes a flexible shroud36, which is folded over seeker dome18in the closed position (FIG. 2). During flight of munition12(FIG. 1), airflow enters flexible shroud36through a relatively small forward opening40. When munition12surpasses a predetermined positive airspeed, the airflow received through opening40exerts pressure on the inner surfaces of flexible shroud36sufficient to cause shroud36to unfold or unfurl and thereby expose underlying seeker dome18. Stated more simply, dome cover20opens or unfurls during munition flight as flexible shroud36fills with wind flowing (relative to munition12) in a fore-aft direction during munition flight. As indicated inFIG. 2, flexible shroud36may be folded over seeker dome18in a spiral pattern such that the folds of shroud36are twisted about a longitudinal axis of munition body16; however, the manner in which shroud36is folded over seeker dome18may vary amongst different embodiments.

Forward opening40may or may not provide a flow path through dome cover20to the interior of cover20and, therefore, to underlying seeker dome18. If forward opening40provides a flow path through dome cover20, it is preferred that any such flow path is relatively torturous or is otherwise sized and shaped to prevent or minimize the penetration of exhaust to the interior of dome cover20. Seeker dome18may also be further protected from exhaust penetration through cover20by a protective membrane37(partially visible inFIG. 2), which may be positioned between the interior surface of dome cover20and the exterior surface of seeker dome18. In one embodiment, protective membrane37assumes the form of a relatively thin sheet of paper or other material, which is retained in place by its disposition between cover20and dome18and possibly adhesively attached to the interior of cover20or munition body16. To further block any exhaust leakage paths through cover20, it may also be desirable to seal dome cover20by, for example, applying one or more layers of a coating material over the exterior of cover20. Sealing of dome cover20may also deter the desiccation or drying-out of cover20during prolonged storage of AUR10in dry (e.g., desert) environments.

Self-deploying dome cover20further includes an aft collar portion38, which is joined to the aft circumferential edge of flexible shroud36; e.g., collar portion38and flexible shroud36may be integrally formed as a unitary sheet or sleeve of material, as described below. Collar portion38has a generally annular shape and extends around an outer circumference of munition body16proximate seeker dome18. Collar portion38, and more generally self-deploying dome cover20, includes an aft opening through which a forward portion of munition body16is received, as generally shown inFIGS. 4 and 5(described below). Flexible shroud36and collar portion38are conveniently, although not necessarily, integrally formed as one or more sleeves of lightweight, flexible material, such as a sheet of paper, fabric, or plastic. Notably, in embodiments wherein dome cover20is fabricated from such a flexible, lightweight material, jettison of dome cover20does not produce heavy, high energy debris that could increase the risk of foreign object damage to nearby objects. If desired, the outer surface of dome cover20may be coated with an ablative or thermally insulating material to provide added thermal isolation from hot exhaust flow during munition launch. In one preferred embodiment, dome cover20is formed from a polymeric film, such as the Kapton® brand polyimide film commercially available from E. I. du Pont de Nemours and Company (commonly referred to simply as “DuPont”), and coated with a silica-based ablative material.

Collar portion38is attached to munition body16to ensure that self-deploying dome cover20remains securely in place over seeker dome18until the desired time of deployment. In a preferred embodiment, collar portion38is attached to munition body16in a manner that enables collar portion38, and therefore dome cover20, to detach from body16in response to drag forces exerted on dome cover20when in the open position (FIG. 3); e.g., collar portion38may be adhesively attached to munition body16utilizing, for example, one or more strips of tape. In further embodiments, collar portion38may be detachably mounted to munition body16utilizing one or more pins, tabs, circumferential restraints (e.g., C-shaped springs or clamps), or other mechanical means capable of disengaging from munition body16and/or collar portion38at the desired time of deployment. In the illustrated example, inflight detachment of dome cover20is facilitated in at least two manners. First, as may be most easily appreciated by referring toFIG. 3, flexible shroud36is imparted with a frustoconical geometry such that the inner diameter of shroud36increases when moving in an aft-fore direction; as a result, forced tearing of flexible shroud36occurs during munition flight as shroud36fully opens and continues to fill with pressurized airflow. Second, as indicated inFIG. 3by dashed line42, dome cover20is scored, perforated, or otherwise structurally weakened in a longitudinal direction to promote tearing when cover20is subjected to post-deployment drag forces. By facilitating post-deployment detachment of dome cover20in this manner, any drag impulse created by the deployment of dome cover20during munition flight can be minimized. In addition, the likelihood of dome cover20catching on wings24, TVC vanes26, or other external component of munition12(e.g., a pitot tube) is reduced by designing dome cover20to tear or separate into at least one strip of material.

FIGS. 4 and 5are isometric views of guided munition12illustrating self-deploying dome cover20prior to and after deployment, respectively. Referring initially toFIG. 4, guided munition12is illustrated during or immediately after munition fly-out from container14(not shown for clarity). At this juncture, guided munition12is enveloped in a forward-expanding exhaust plume (also not shown), which flows munition12in an aft-fore direction and imparts guided munition12with a negative airspeed. As indicated inFIG. 4by arrows46, the forward-expanding exhaust plume flows over the outer surface of self-deploying dome cover20, which resides in a non-deployed or covering position to shield seeker dome18(FIG. 5) from the deposition of chemicals, soot, and other such exhaust materials. Due to its aerodynamic shape, as taken along the longitudinal axis of guided munition12in an aft-fore direction, self-deploying dome cover20remains securely in its closed position to block dome contamination even in the presence of high velocity aft-fore exhaust flow. Dome cover20is thus able to effectively prevent or significantly minimize contamination of seeker dome18during launch and fly-out of guided munition12from launch container14.

FIG. 5illustrates guided munition12after guided munition12has surpassed the predetermined airspeed during munition flight. As can be seen inFIG. 5, self-deploying dome cover20has deployed or opened in response to aerodynamic forces acting on cover20and, specifically, in response to the fore-aft airflow flowing into cover20through forward opening40(represented inFIG. 5by arrows48). After deploying in this manner, self-deploying dome cover20may subsequently detach from munition body16in response to drag forces exerted on dome cover20. In this manner, dome cover20reliably self-deploys at a desired juncture during munition flight without the aid of an actuator, timing electronics, or other such conventionally-employed devices. Furthermore, dome cover20is highly compact when in a closed or covering position (FIGS. 2 and 4) and, consequently, requires the provision of little to no additional clearance within launch container14(FIG. 1). As a still further advantage, in embodiments wherein dome cover20is at least partially formed from a lightweight, flexible material of the type descried above, dome cover20is lightweight, readily portable, and produces little to no high-energy debris upon deployment.

It should thus be appreciated that there has been provided multiple exemplary embodiments of a guided munition, such as a containerized guided missile, including a dome cover that reliably self-deploys at a desired juncture without the aid of an actuator, timing electronics, or similar devices. Advantageously, the above-described exemplary self-deploying dome covers are relatively compact, inexpensive to implement, and produce little to no high-energy debris upon deployment. The foregoing has also provide exemplary embodiments of a method for equipping a guided munition including a seeker dome with a self-deploying dome cover. In one implementation, the above-described method included the steps of providing a self-deploying dome cover configured to open during munition flight in response to aerodynamic forces acting on the self-deploying dome cover when surpassing a predetermined airspeed, positioning the self-deploying dome cover over the seeker dome, and stowing the guided munition within a launch container. In embodiments wherein the self-deploying dome cover includes a flexible shroud, the step of positioning the self-deploying dome cover over the seeker dome may comprise folding the flexible shroud over the seeker dome.

Although, in the above-described exemplary embodiment, the self-deploying dome cover include a forward or central opening through which fore-aft airflow was received during munition flight, this need not be the case in all embodiments. For example, in lieu of a central opening (or in addition thereto), embodiments of the self-deploying dome cover may include one or more external drag features (e.g., sharp corners or other non-aerodynamic structures), which are formed on or mounted to the exterior of the dome cover and project radially outward therefrom. When exposed to high velocity airflow during munition flight, the drag features exert a pull force on the dome cover in a radially-outward direction to cause the dome cover to unfold or otherwise open when the guided munition surpasses a predetermined airspeed.