Methods and apparatus for fast action impulse thruster

Methods and apparatus for a fast action impulse thruster according to various aspects of the present invention may comprise a projectile comprising an impulse thruster system. The impulse thruster system may comprise a guidance system and a fast action impulse thruster system. The guidance system may control the trajectory of the projectile, for example by activating the fast action impulse thruster system to adjust the projectile's trajectory. The fast action impulse thruster system may be configured such that it may provide an impulse force to guide the projectile with a reaction time that is not affected by the rotational velocity of the projectile. The impulse force may be achieved by ejecting at least one mass from the projectile at high velocity such that a resulting momentum exchange may alter the trajectory of the projectile. The fast action impulse thruster system may also be configured in such a way so as to provide a significant improvement to the overall safety during the production, assembly, and handling of the projectile.

BACKGROUND OF INVENTION

In the realm of enemy combat, ballistics are continually developed in an attempt to acquire a combative edge. For example, long range projectiles, such as missiles, mortars, and the like were developed to more beneficially engage the enemy at long ranges to limit close range, hand to hand or close fire combat. However, the effectiveness of such long range projectiles may be limited by a variety of constraints. Two such common constraints are limited firing range and/or inaccurate targeting. For instance, an artillery-fired projectile may comprise a limited range due to a maximum muzzle velocity for a given combination of the projectile, a barrel to direct the launch of the projectile, and a propellant to “drive” the projectile. Frequently, targets beyond the limited range cannot be effectively reached. Additionally, the artillery-fired projectile may comprise of a fixed trajectory upon firing. As a consequence, if the fixed trajectory is not accurately aligned to the intended target, upon firing the projectile, the projectile may miss its intended target. Other factors can also reduce the accuracy of the projectile, such as, atmospheric conditions, variations in the aerodynamic properties of a given projectile, and/or the like.

Limited range and accuracy may have a number of negative effects in combat situations. For example, to compensate for inaccurately launched projectiles, launches of multiple projectiles may be needed to ultimately strike the intended target. Thus, the time to launch multiple projectiles may extend the engagement of the enemy, which in turn increases the cost of enemy engagement operations and jeopardize the lives of combatants who must experience such extended engagement times to service the enemy targets.

A number of systems have been developed to overcome these constraints. For instance, to overcome limited range, integrated rocket systems such as an M5419A1 rocket assisted projectile have been developed with additional propulsion. While integrated rockets comprising additional propulsion may increase range, these types of rocket systems do not necessarily improve accuracy.

To improve accuracy, some projectiles may comprise guidance systems comprising control surfaces that are configured to direct the projectile during flight. For example, these guidance systems may comprise deployable fins that modify the aerodynamic properties of the projectile to affect its trajectory. While guidance systems may serve to direct the flight of the projectile, such guidance systems may also add substantial complexity and weight to the projectile, and the inherent drag of the aerodynamic controls may further reduce the range of the projectile. Moreover, conventional flight control surfaces may be less effective on projectiles comprising large rotational velocities because the control surfaces cannot react quick enough to overcome the rotation of the projectile.

SUMMARY OF THE INVENTION

Methods and apparatus for a fast action impulse thruster according to various aspects of the present invention may comprise a projectile comprising an impulse thruster system. The impulse thruster system may comprise a guidance system and a fast action impulse thruster system. The guidance system may control the trajectory of the projectile, for example by activating the fast action impulse thruster system to adjust the projectile's trajectory. The fast action impulse thruster system may be configured such that it may provide an impulse force to guide the projectile with a reaction time that is not affected by the rotational velocity of the projectile. The impulse force may be achieved by ejecting at least one mass from the projectile at high velocity such that a resulting momentum exchange may alter the trajectory of the projectile. The fast action impulse thruster system may also be configured in such a way so as to provide a significant improvement to the overall safety during the production, assembly, and handling of the projectile.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention may be described in terms of functional block components and various processing steps. Such functional blocks and steps may be realized by any number of technologies, manufacturing techniques, and/or operational sequences configured to perform the specified functions and achieve the various results. For example, the present invention may employ various materials, software programs, communications systems, and data storage systems, for example, satellite positioning systems, inertial guidance systems, and/or the like, which may carry out a variety of functions. In addition, the present invention may be practiced in conjunction with any number of applications including guided projectile systems, guided missile systems, ordnance transportation devices, etc., and the system described is merely one exemplary application for the invention.

Various representative implementations of the present invention may be applied to any system for projectile propulsion, projectile navigation, projectile guidance, and the like. Certain representative implementations may comprise, for example, an impulse thruster system configured to couple to a projectile and direct the projectile to an intended target according to a guidance kit. Methods and apparatus for fast action impulse thruster may operate in conjunction with a launch system, such as an artillery barrel, and/or an auxiliary control system.

Referring now toFIG. 1, methods and apparatus for a fast action impulse thruster may operate in conjunction with a projectile100. The projectile100may comprise any system that is configured to travel, either with an on-board propulsion system or ballistically. The projectile100may comprise a system to deliver a payload, such as a conventional artillery-fired munition114coupled to a fuze110and a detonator120. According to various aspects of the present invention, the projectile100may further comprise an impulse thruster system112coupled to a guidance system116. At least a portion of the projectile100may be selected from prefabricated, preexisting, and/or off-the-shelf parts and components, such as artillery shells, explosively formed projectiles, naval munitions, grenades, solid fuel rockets, solid fuel thrusters, circuit cards, metal casings, nozzles, control systems, and/or the like. The projectile100may comprise one or more subsystems, and conventional components may be modified to operate in conjunction with other systems.

In the present embodiment, the projectile100may comprise a spin stabilized projectile comprising a rotational velocity of about 18,000 revolutions per minute (RPM), but other exemplary embodiments may comprise projectiles comprising rotational velocities greater than or less than the RPM's given for the exemplary embodiment. For example, projectiles comprising various masses, lengths, architectural configurations, etc., may comprise other rotational velocities commensurate with the functioning of the projectiles.

In accordance with exemplary embodiments of the present invention, the munition114may comprise ordnance configured to detonate in response to a signal from the fuze110. The munition114may comprise any system for delivering an explosive, wherein the explosive may comprise, a conventional explosive, an unconventional explosive, such as nuclear material, a chemical agent, a biological agent, and/or the like. The munition114may also be configured to provide ordnance comprising a specified impact characteristic, such as temperature, electromagnetic output, pattern of particulate matter, electronic interference pattern, pressure, and/or the like. The munition114may further be configured for insensitive munition features, such as to accommodate handling during delivery to a launch vehicle.

The munition114may comprise various materials, dimensions, and/or geometries. In one example, the munition114may comprise a maximum allowable circumference for a given artillery barrel and a specified detonation characteristic. Among other examples, the munition114may comprise a specified mass of high explosive material. In still other examples, the mention114may comprise an explosively formed projectile configured to operate within a specified geometry, such as a 105 mm artillery projectile, a mortar barrel, and/or the like.

In accordance with exemplary embodiment of the present invention, the fuze110may be configured to selectively actuate the munition114. The fuze110may comprise any system for triggering a munition114, such as the detonator120, a switch, a preliminary explosive, a squib, and/or the like. The fuze110may trigger the munition114in response to a specified condition, such as, after a specified passage of time from launch, upon achieving a specific altitude, after reaching a specific position along a trajectory, upon experiencing a specific pressure, and/or the like. In the present embodiment, the fuze110may comprise a standard 105 mm artillery fuze disposed in a fuze well of the projectile100. As another example, the fuze110may be a naval fuze disposed toward the fore portion of the projectile100, such as within a nosecone. Furthermore, depending on the munition114or other appropriate criteria, the fuze110may be configured to chemically, mechanically, and/or electrically actuate the munition114.

In accordance with an exemplary embodiment of the present invention, the projectile100may comprise a casing118to at least partially contain the munition114, the fuze110, and/or other projectile components. The casing118may comprise any appropriate casing, such as a conventional shell comprising an interior cavity to contain the munition114. In the present exemplary embodiment, a steel casing118may: contain a high explosive munition114, receive a standard artillery fuze110, and provide the high explosive munition114with insensitive munition characteristics. An exemplary casing118may also be configured to fragment and/or shatter in response to detonation of the munition114. Referring toFIG. 1of the present embodiment, the casing118may be configured to contain the impulse thruster system at a position that, in one example, is at or near the center of mass of the projectile100.

In accordance with exemplary embodiments of the present invention, the projectile100may comprise the impulse thruster system112, wherein the impulse thruster system112may be configured to impart a force off the longitudinal axis of the projectile100, such as a force that may be substantially transverse to the longitudinal axis of the projectile100. The force provided by the impulse thruster system112may be supplemental to any force imparted by a launch system, such as an artillery barrel launch system. The impulse thruster system112may comprise any system for generating force, including a mass ejection drive system, a solid fuel rocket engine, a jet engine, a control surface, and/or the like. Referring toFIG. 2of the present embodiment, the impulse thruster system112may comprise at least one or more fast action impulse thrusters210arranged, for example, radially, around the longitudinal axis of the projectile100, at or near the center of mass of the projectile100, and/or any other positional configuration to impart the force as discussed. The impulse thrusters210may be configured to react within an impulse period that is faster than the rotational velocity of the projectile100.

The fast action impulse thrusters210may be arranged such that the force generated by their activation acts substantially transverse to the longitudinal axis of the projectile110and/or through the center of mass of the projectile100. In such an arrangement, actuation of the impulse thruster system112may be configured to produce a substantial force to alter the course of the projectile during flight, yet prevent producing a significant torque on the projectile100.

The number, properties, and arrangement of the fast action impulse thrusters210may be configured in any suitable form. In some projectiles100, multiple rows of fast action impulse thrusters210may be arranged along the surface of the projectile100, but in other exemplary embodiments a single row of fast action impulse thrusters210may be implemented. In addition to single or multiple rows, the number of fast action impulse thrusters210in a row may also be varied. Further, the impulse thruster system112may comprise various types of fast action impulse thrusters210to provide impulses of various magnitudes, durations, directions and/or the like.

In accordance with exemplary embodiments of the present invention and with reference now toFIGS. 3A,3B, and3C of the present embodiment, the fast action impulse thrusters210may individually comprise an energetics assembly301and an electronics assembly302. The energetics assembly301and the electronics assembly302may be partitioned to increase system safety. Among various exemplary embodiments, the electronics assembly302may not contain any energetic material, thereby allowing it to be tested during assembly and prior to installation of the energetics assembly301. In a complete fast action impulse thruster210assembly, the energetic material located in the energetics assembly301may line up with and complete the train in the electronics assembly302.

In accordance with exemplary embodiments of the present invention, the energetics assembly301may be configured to eject at least one mass from the projectile100at high velocity. The energetics assembly301may comprise any system for ejecting the at least one mass such as, an explosive ordnance or exhaust gases from the projectile's propellant. In the present embodiment, the energetics assembly301may develop thrust by primarily ejecting the at least one mass through the explosion of insensitive munitions. The resulting force is several times larger than methods which rely on exhaust gases alone. Referring toFIG. 3A, the energetics assembly301may comprise an energetic312, a flyer plate310, and a seal320. The flyer plate310substantially covers the energetic312on one end and the seal320substantially covers the energetic312on the other end.

In accordance with exemplary embodiments of the present invention, the flyer plate310may comprise a mass that may be ejected from the body of the projectile100such that the resulting force of the ejection may be used to alter the trajectory of the projectile100. The flyer plate310may comprise of any suitable natural or synthetic materials, such as metals, alloys, ceramics, high density polymers, composites, and the like. In one embodiment, the mass may comprise a metallic material ranging from about 0.06 ounces to about 8 ounces.

For example, in an exemplary configuration, each of the plurality of fast action impulse thrusters210may comprise a metallic flyer plate310comprising a mass of about 0.4 ounces that is configured to be ejected from the projectile100at a high velocity when the fast action impulse thruster210is activated. The fast action impulse thruster210may provide an impulse from about 10 to about 20 microseconds in duration. The combination of the low mass of the flyer plate310and the high velocity with which it is ejected, may create a momentum exchange to alter the trajectory of the projectile100as described.

Referring toFIG. 3A, in the present embodiment, the flyer plate310may further be configured to secure to the impulse thruster system112via engagement threads322, wherein the engagement threads322may shear off when the fast action impulse thruster210is activated. The flyer plate310may, however, be configured to secure to the impulse thruster system112to the projectile100in any suitable manner to allow the flyer plate310to be ejected from the projectile100, such as with a pin, a hook, a spring, a compression fitting, and/or the like.

In accordance with exemplary embodiments of the present invention, the energetic312may comprise an explosive charge to cause the ejection of the flyer plate310from the projectile100. The energetic312may comprise any system or component necessary to provide the necessary impulse force to eject the flyer plate310from the projectile100. Among various embodiments, a typical barrel launched projectile100may be imparted with a rotational velocity that is used to help stabilize the projectile100during flight, and the impulse reaction time of the energetic312may comprise an important factor as the rotational velocity of the projectile100increases. For example, in the present spin stabilized projectile100embodiment, the energetic312may comprise an insensitive explosive comprising an impulse reaction time of about 100 microseconds or less. The impulse reaction time may provide for actuation of the energetic312within plus or minus fifteen degrees of the desired position on projectiles comprising a rotational velocity up to about 18,000 revolutions per minute.

Among various exemplary embodiments, the amount of the energetic312in a fast action impulse thruster210may vary depending on the mass of the flyer plate310or on the desired impulse force. The impulse thruster system112may comprise fast action impulse thrusters210with a single energetic312charge or comprise energetics312that may comprise several different levels of charge. Alternative embodiments may comprise an energetic312comprising a slower reaction time that corresponds to specific rotational characteristics of a given projectile100.

In accordance with exemplary embodiments of the present invention, the electronics assembly302may activate the energetic312thereby causing the Over plate310to eject from the projectile100. The electronics assembly302may comprise any system that can receive an activation signal from the guidance system116and then activate the energetic312. Referring toFIG. 3Bin the present embodiment, electronics assembly302may comprise an initiator316and a control circuit314.

In accordance with exemplary embodiments, the initiator316may trigger the energetic312. The initiator316may comprise any system or component to activate the energetic312such as a mechanical or electromechanical detonator, an exploding bridgewire detonator, a slapper detonator, and/or the like. In the present embodiment, the initiator316may comprise a low energy exploding foil initiator that is coupled to the energetic312and may be configured to activate the energetic312after receiving a signal from the control circuit314. Alternative embodiments for the initiator316may comprise using a detonator or microelectromechanical system coupled to a safe and arm device for each energetic312. The safe and arm device may provide safe handling properties to allow handling the initiator316by personnel. For example, safe handling may be provided electronically by use of an exploding foil “slapper” detonator or mechanically by use of a microclectromechanical safe and arm.

In accordance with exemplary embodiments, the control circuit314may transmit a signal to the initiator316in response to a trigger or event from the guidance system116. The control circuit314may be configured in any manner to provide the necessary input to the initiator316, such as by a full integrated circuit assembly or the triggering signal may be sent by stand alone electrical components, such as capacitors and/or the like. Referring toFIG. 3of the present embodiment, the control circuit314may be coupled to the initiator316, but alternative embodiments may comprise the control circuit314positioned separate from the impulse thruster system112. Among various embodiments, the control circuit314, the initiator316, the impulse thruster system112. as well as any other components described may communicate among each other by either wired or wireless signals to activate the initiator316.

In accordance with exemplary embodiments of the present invention, the guidance system116may control the operation of the impulse thruster system112. The guidance system116may also control the operation of the projectile100according to any appropriate mechanisms and/or criteria. For example, the guidance system116may determine the position of the projectile110and/or a time of flight of the projectile100, and selectively actuate the impulse thruster system112to achieve a desired position and/or trajectory. The guidance system116may also control the arming of the fuze110by providing position data.

In the present embodiment, the guidance system116may comprise a position sensor and a rotation sensor, such as an accelerometer, a velocimeter, a magnetometer, a satellite positioning system, an optical sensor, and/or the like. The two sensors may be used to identify the position of the projectile100in space and/or the rotational velocity of the projectile100. This information may then be used to determine if the impulse thruster system112is should be activated to alter the trajectory of the projectile100. When actuation of the impulse thruster system112is deemed appropriate, the guidance system116calculates the amount of force required to alter the trajectory, which energetic312will be fired, as well as the timing of the firing.

In an exemplary embodiment, if the guidance system116determines an initial trajectory of the projectile100will result in the projectile100landing ten meters to the left of an intended target, the guidance system116will calculate the rotational velocity of the projectile100, the necessary force required to correctly alter the trajectory of the projectile100, and then actuate the impulse thruster system112to fire off the appropriate energetics312. The fired energetic312will then eject the flyer plates310when they rotate to a position such that the resulting incremental forces will redirect the projectile100to an arrival point ten meters to the right.

Among various exemplary embodiments, the guidance system116may also communicate with other systems. For example, the guidance system116may be configured to selectively actuate other systems on the projectile100such as control surfaces. As another example, the guidance system116may be configured to receive and/or transmit information tracking systems, satellite positioning systems, and/or the like.

In accordance with exemplary embodiments of the present invention, in operation, the projectile100may be initially positioned, packaged, transported, and/or installed in a launch vehicle such as an artillery barrel, warship, and/or the like. A target may then be selected, such as by receiving position information via real-time intelligence and/or surveillance operations, approximating target position information based on dated intelligence and/or surveillance operations, and/or via sensory equipment.

Among various exemplary embodiments, providing the intended target's position information to the guidance system116may be accomplished in various manners. For example, providing the guidance system116of the projectile100with the targets position information may comprise, directly transferring the target's position information to the projectile100prior to launch, transmitting the target's position information during flight of the projectile100, and/or calculating the target's position information via onboard systems after initiation of the projectile100. The specific manner to provide the guidance system116with the target's position information may depend upon the type of target to be destroyed. For example, while a fixed target comprising a known position may be appropriate for pre-initiation (pre-launch) input into the guidance system116, a moving target may comprise a variable position, thus an on-board tracking device such as an optical tracking system (not shown) may be used to provide the guidance system116with the target's position information.

In accordance with exemplary embodiments of the present invention, the projectile100may be prepared for launch, for example by aligning a launch vehicle to aim the projectile100at a specified (intended) target, triggering the launch vehicle, and/or the like. For example, the projectile100may be loaded and triggered via an artillery piece, a shoulder-fired rocket, or any other appropriate launch system. The projectile100may further be configured such that the projectile100translates and/or rotates toward the intended target.

Among exemplary embodiments, the projectile100may be self-guided or remotely guided towards the intended target. For example, a projectile100that is self-guided may compare its position and/or orientation relative to an intended target's position and adjust the projectile's position and/or orientation accordingly. In the present embodiment, the guidance system116may calculate the guidance parameters of the projectile100by receiving guidance signals, such as global positioning system signals. Alternatively, the guidance system116may receive guidance information from an onboard inertial guidance system, an onboard sensory device, such as an optical sensor, and the like. Guidance information may comprise linear and/or angular acceleration, linear and/or angular velocity, rate of linear and/or angular acceleration, rotational velocity, and/or the like. Such guidance information may pertain to the position, acceleration, velocity, rotation rate of the projectile, and/or the like, for the projectile100at a particular time, and in some embodiments the guidance information may be calculated for a future time. In addition, such guidance information may be gathered over multiple time intervals to determine the actual position, acceleration, velocity, and/or the like, for the projectile100.

In accordance with exemplary embodiments, the guidance system116may evaluate position information. For example, if the trajectory of the projectile100is such that both range and accuracy are adequate to impact the target, no action may be necessary. However, if the trajectory of the projectile100is such that at least one of the range and accuracy is inadequate to impact the target, the impulse thruster system112may be actuated.

In accordance with exemplary embodiments, the guidance system116may selectively actuate the impulse thruster system112to alter the flight of the projectile100to increase the likelihood of striking the target. For example, the impulse thruster system112may be actuated in short bursts when specific fast action impulse thrusters210are in the appropriate position. The guidance system116may use the rotational velocity of the projectile100and accuracy data to determine how much force is required to alter the trajectory and at what direction on the projectile100that force should be imparted. The guidance system may then signal the impulse thruster system112to initiate the appropriate energetic312when the energetic312has rotated into the desired position. When the energetic312is actuated it ejects the flyer plate310and the resulting momentum exchange imparts a force to the projectile100resulting in an alteration to the trajectory of the projectile100. This process is then repeated until enough flyer plates310have been ejected from the projectile100to result in a complete course correction to the projectile100.

In accordance with exemplary embodiments, the process of determining the position of the projectile100, comparing the position of the projectile100to a desired position, for example, an intended target, and adjusting the position of the projectile100may be repeated while the projectile100is in flight. Upon arriving at the intended target, the munition114may be activated, for example by programming the fuze110, detonating the munition114, and/or the like. Actuation of a munition114may be an automatic response to the position of the projectile100, such as in response impact of the projectile100with the intended target, proximity of the projectile100to the intended target, a specified time interval from initiation of the projectile100, a specified elevation of the projectile100, and/or the like. Alternatively, the fuze110may be in communication with the guidance system116such that position information as determined by the guidance system116may selectively trigger the munition114via the fuze110.

In the foregoing specification, the invention has been described with reference to specific exemplary embodiments. Various modifications and changes may be made, however, without departing from the scope of the present invention as set forth in the claims. The specification and figures are illustrative, rather than restrictive, and modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents rather than by merely the examples described.

For example, the steps recited in any method or process claims may be executed in any order and are not limited to the specific order presented in the claims. Additionally, the components and/or elements recited in any apparatus claims may be assembled or otherwise operationally configured in a variety of permutations and are accordingly not limited to the specific configuration recited in the claims.