The present invention relates to munitions. More particularly, the present invention relates to large-caliber naval and artillery munitions.
In the recent past, there has been considerable effort expended in providing in-flight control of projectiles fired from naval guns and from artillery pieces. Such control accommodates the in-flight environment by correcting for such things as wind and other atmospheric effects, permitting the projectile to be directed to a much smaller target foot-print than conventional uncontrolled projectiles. Such control is extremely important in minimizing collateral damage to personnel in close proximity to the target. Further, such control permits the targeting of specific targets located in close proximity to structures and individuals that are nearby and are not targeted. In the past, such control has been provided by guidance navigation and control units (“GNC”) that have significant mass and volume. Such mass and volume has a number of deleterious effects on the munition itself, such as reduced warhead size and reduced range. In particular, when used with a 155 millimeter projectile, the prior art GNC units had such mass and volume that they precluded the use of a rocket motor in the munition itself, thus limiting range. Further, the 105 millimeter munition has never been fitted with a GNC unit because the prior art GNC units would simply take up a significant portion of the volume of the munition that is reserved for a warhead. Accordingly, there is a need in the industry for a GNC unit that may be retrofitted to an existing large-caliber munition that is small enough to not significantly diminish the warhead of the munition or to permit the installation of a rocket motor without significantly diminishing the warhead portion.
The present invention substantially meets the aforementioned needs of the industry. Advantages of the present invention are many, including that it is a stand-alone unit. In the past, GNC units were integrated into the round and shipped with the round. By making the miniaturized GNC unit of the present invention a stand-alone item, the GNC unit can be shipped by itself much like fuses are currently handled. The further advantage of this is that the GNC unit of the present invention can be used with a number of different munitions and assembled to the munition prior to the deployment of the round in much the same manner that fuses are currently assembled to a munition.
Additionally, the lethality and range of a particular munition are increased by miniaturizing the GNC unit. This is effected through the ability to allocate more of the available projectile length to warhead and/or rocket motor. It should be noted that projectiles, especially the 155 millimeter and 105 millimeter projectiles are maximum length constrained in order to fit within existing ammunition handling and logistical systems.
The lethality is specifically increased by allowing more volume for the warhead (deriving from increased warhead length reallocated from a miniaturized GNC unit). Such expanded volume permits the increase of either energetic material (explosive) or casing material (which generates shrapnel of varying masses depending upon total thickness), as the target set may dictate.
Range is increased by allowing more volume for the rocket motor (deriving from increased rocket motor length reallocated from a miniaturized GNC unit) in order to increase the total mass of rocket motor propellant carried within the projectile. More rocket propellant translates directly into more stored energy which may then be applied to propel the projectile a further distance before gliding must ensue.
The fact that the miniaturized GNC unit allows for increasing the size of the rocket motor has other performance advantages as well. Since there is more rocket motor to propel the specific munition during flight, g's (the acceleration of gravity) at launch of the projectile can be reduced. Reduced g's at launch means that the casing for the rocket motor can be further reduced in size, thereby permitting an even larger rocket motor. Additionally, a typical 155 millimeter cannon fires projectiles at about 16,000 g's of maximum acceleration, whereas a 105 millimeter projectile is typically launched at about 24,000 g's of acceleration. The projectile optimization afforded by the miniaturized GNC unit of the present invention allows reduced launch loads to approximately 13,400 g's for the 155 millimeter projectile and 18,000 g's for the 105 millimeter projectile. Reducing such g's as noted above, means that significantly less propellant is needed to fire the projectile from the cannon. Reducing the amount of propellant required has the further advantage of increasing barrel life of the cannon by decreasing the temperature of the gasses required to launch the projectile. A reduction in the temperature of such gasses from 3,000 degrees fahrenheit to 2,600 degrees fahrenheit has a very significant effect on increasing barrel life. Such reductions are achievable by using the miniaturized GNC unit of the present invention.
The present invention is as GNC unit that provides a munition with the functionality of a guided weapon. The GNC unit includes a navigation system to establish information on current position, a guidance system to provide information on where to go and the desired path or trajectory and a control functionality to enable the unit to follow guidance commands that originate within the guidance system. To effectuate the commands, an adjustable canard system is used to effect flight correction.
The GNC unit design uses a modular approach to minimize footprint while increasing efficiency. The main components include a Forward Integrated Electronics Subsystem (FIES), a GPS/TM Antenna Unit (GTAU), a power and control subsystem, a Guidance Electric Unit (GEU), a main battery, a fire control board, and a wire harness. The GNC unit is disposed on the projectile by way of roller bearing isolation system so that the GNC unit is isolated from the projectile body.
For guided flight using canards, extended range performance and controllability are the driving requirements. Current designs for guided munitions typically involve four canard surfaces to provide aerodynamic control and range. However, four canards use a significant amount of space within the nose of the projectile. Thus the current invention saves space by combing fewer, smaller canards with a bearing stabilized GNC assembly. The number of canards are reduced due to the ability to isolate the GNC from the payload section in flight. The GNC unit contains a pilot diameter and external threads for interfacing with the payload section of the munition.
Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples shown.
a is a functional diagram of the GNC unit;
A gun launched round capable of incorporating the miniaturized GNC unit of the present invention is shown generally at 10 in the figures. The miniaturized GNC unit of the present invention is show generally at 12. From top to bottom in
The topmost exemplary round 10 in the depiction of
Generally, each round 10 includes a standardized threaded bore 17 that extends into the warhead 16. Typically, the round 10 is shipped without a fuse and the fuse is later assembled to the round 10 by threading into the standardized threaded bore 17 proximate the location at which the round 10 is to be fired. Significantly, the GNC unit 12 of the present invention is designed to be threaded into the standardized threaded bore 17 of the round 10. Accordingly, the round can be fitted with a standardized fuse for the GNC unit 12, as desired and the GNC unit 12 of the present invention may be used on a number of different types of munition having the standardized threaded bore 17.
Rear stabilizers 22 are disposed at the rear-most portion of the round 10. The rear stabilizers 22 are shiftily mounted to the round 10 by means of hinges 24. In the depictions of
Referring to
Proceeding rearward from the FIES 30, the next subsection is the GPS telemetry antenna unit (“GTAU”) 34. The power and control subsection (“PCS”) 36 is disposed interior to the GTAU 34. Rearward of the PCS 36 is the guidance electronics unit (“GEU”) 38. The battery 42 is disposed rearward of the GEU 38 and is located between the GEU 38 and the fuse, safe, and arm communications device 40.
An important feature of the GNC unit 12 is that the GNC unit 12 is isolated in flight from the rotation of the round 10 that is imparted by the rifling of the barrel from which the round 10 is fired. This isolation is effected by the bearings 44. The inner support of the bearings 44 is rotationally isolated from the outer support of the bearings 44, the outer support being fixedly coupled to the round 10 and rotating therewith.
Referring to
The GTAU 34, as depicted in
The PCS 36 includes the PCS outer structural cone or skin 54, noted above, and includes a pair of canard slots 56 that are brought into registry with the canard slots 52 when the skin 54 is disposed within the interior space 50 defined in the GTA unit 34.
Referring to
The canard actuation subsystem 61 is depicted in
A crank arm 67 is coupled to the ball screw nut 66. The crank arm 67 is coupled to a shaft 68 which in turn is coupled to the canard 69. Translation of the ball screw nut 66 on the ball screw 65 causes the shaft 68 and accordingly the canard 69 to rotate about the axis 57. The axis 57 is disposed orthogonally with respect to the longitudinal axis 46 (see
It is understood that there are two canards 69 utilized with the GNC unit 12. Accordingly, there are two opposed, mirror image canard actuation subsystems 61. Unlike prior art GNC projectile control systems that employed four canards, it has been determined that two opposed canards described above are adequate to provide the necessary inflight control for the round 10. Such design considerably simplifies the necessary mechanical features of the GNC unit 12 of the present invention as compared to prior art GNC units.
Turning to
An interiorally defined mating surface 82 provides for a mating with the interior housing 58 of the PCS 36. The largest diameter inner margin 84 of the skin 54 is a mating surface for the GEU 38. The rear margin 86 of the skin 54 further comprises a mating surface for the GEU 38. Moving forward in the skin 54, the next interior marginal surface is the PCS retaining ring 88. PCS retaining ring 88 is threaded in order to receive the PCS retaining ring 90.
PCS retaining ring 90, as depicted in
Referring to
Moving rearward on the GNC unit 12, as depicted in
Coupling of the PCS 36 to the portion of the GNC unit 12 containing the GEU 38 and the battery 42 is effected by the previously described PCS retaining ring 90. In the depictions of
Significantly, the structure of the aft portion of the GNC unit 12 includes an outer spindle 102 and an inner spindle 104. The outer spindle 102 and the inner spindle 104 are spaced slightly apart such that the two spindles 102, 104 are rotatable with respect to one another about the longitudinal axis 46. The ability of the two spindles 102, 104 to rotate with respect to one another is effected by the bearing unit 106. Outer spindle 102 has a bearing retaining surface 108 that is outboard of a bearing retaining surface 110 defined on the outer margin of the inner spindle 104.
The bearing unit 106 includes two bearing units 112a, b spaced apart by a spacer ring 114. Each of the bearing units 112a, b has an outer ring 116 and an inner ring 118. A bearing race 128a, b is defined in the respective inner margin of the outer ring 116 and outer margin of the inner ring 118. A bearing 122 is born in each of the respective braces 120a, 120b. The outer margin of each of the bearing rings 112a, b is born on the bearing retaining surface 108 of the outer spindle 102. The inner margin of the respective bearing rings 112a, b is borne on the bearing retaining surface 110 of the inner spindle 104.
The bearing unit 106 is held in place by two different retainers, one bearing on the respective outer ring 116 and one bearing on the respective inner ring 118. The bearing retainer ring 130 is threadedly coupled to the outer spindle 102 and bears on the outer ring 116. The bearing retainer ring 130 has threads 132 defined on the outer margin thereof.
The main retainer 138 has threads 140 defined on the inner margin thereof. The threads 140 engage the threads 142 defined on the retainer margin 144 of the inner spindle 104. Thus, the main retainer 138 bears on the inner ring 118 of the bearing rings 112a, b.
As depicted in
As depicted in
Functionally, the FSA communication board 40 communicates from the GNC unit 12 to the remainder of the exemplary round 10. The main bit of information so communicated is the fuzing command for detonation of the exemplary munitions 10. This command must be transmitted from the stabilized (non-spinning) GNC unit 12 to the spinning remainder of the exemplary round 10. Functionally, the battery 42 provides electrical power to the GNC unit 12.
The main components of the GNC unit 12 include the FIES 30, the GTAU 34 formed on the PCS skin 54, the wire harness 32, the PCS 36, the PCS retainer 90, the GEU 38, the assembly comprising the outer spindle 102, the inner spindle 104, and the bearing unit 106, the battery 42, the FSA communications 40 and finally, the battery retaining ring 155. To assemble the GNC unit 12, the first step is to attach the FIES 30 to the assembly comprising the GTAU 34 and the PCS skin 54. The second step is to attach the wire harness to the FIES 30. The third step is to insert the PCS 36 into the PCS skin 54 and retain it therein by means of the PCS retaining ring 90. The next step is to insert the GEU 38. The next step is to couple the assembly comprising the spindles 102, 104 and bearing unit 106 to the PCS skin 54. The mating to these two components acts to retain the GEU 38 in position. Finally, the FSA communications device 40 is communicatively coupled to the wire harness 32 and the battery 42 and FSA communications device 40 are put in place and retained in place by means of the battery retaining ring 155.
In flight the two canards 69 are simultaneously deployed by the canard deployment mechanism 61a under command of the GEU 38, as depicted in
Miniaturization of the GNC unit 12 has resulted in a total weight that is less 22.0 lbs. and is more preferably less than 13.2 lbs. The volume of the GNC unit 12 is less than 100 cubic inches and is preferably less than 87.0 cubic inches.
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives.
This application claims the benefit of U.S. Provisional Patent Application No. 61/145,375, filed Jan. 16, 2009, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61145375 | Jan 2009 | US |