WO2010083517A1

WO2010083517A1 - Munition and guidance navigation and control unit

Info

Publication number: WO2010083517A1
Application number: PCT/US2010/021396
Authority: WO
Inventors: William M. Flood, Jr.; Paul M. O'brien
Original assignee: Bae Systems Land & Armaments L.P.
Priority date: 2009-01-16
Filing date: 2010-01-19
Publication date: 2010-07-22
Also published as: US20120181376A1

Abstract

A guidance and control unit assembly for use with a munitions projectile includes a guidance and control unit being roll isolated with respect to the munitions projectile such that roll of the munitions projectile about a projectile longitudinal axis, such roll being imparted to the munitions projectile during the act of launching the munitions projectile, may not be imparted to the guidance and control unit as desired. A munitions projectile is further included.

Description

MUNITION AND GUIDANCE NAVIGATION AND CONTROL UNIT

PRIORITY CLAIM This application claims the benefit of U.S. Provisional Patent Application No.

61/145,375, filed January 16, 2009, the disclosure of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD The present invention relates to munitions. More particularly, the present invention relates to large-caliber naval and artillery munitions.

BACKGROUND OF THE INVENTION

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. SUMMARY OF THE INVENTION

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. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. IA-D are perspective views of selected munitions employing the miniaturized GNC unit of the present invention;

Fig. 2 A is a sectional depiction of the GNC unit; Fig. 2B is a side elevational view of the GNC unit;

Fig. 2C is an exploded view of the GNC unit;

Fig. 3 is a sectional view of a 155 millimeter projectile including the GNC unit of the present invention;

Fig. 4 is a sectional view of the projectile of Fig. 3 with the rocket motor expended; Fig. 5 is a sectional, schematic view of the forward integrated electronics subsection

FIES subcomponent of the GNC unit;

Fig. 6 is a sectional view of the GNC unit with the major subcomponents indicated; Fig. 7 is an exploded view of the GPS-telemetry and antenna unit and the PCS outer structural element. Fig. 8 is a perspective view of the various components that comprise the power and control subsystem (PCS);

Fig. 8 A is a perspective view of the drive system for a canard; Fig. 9 is a perspective view of the structural skin of the PCS subcomponent; Fig. 10 is a sectional perspective view of a portion of the PCS structural skin; Fig. 11 is a perspective view of the PCS retaining ring;

Fig. 12 is a sectional elevational view of the forward portion of the GNC unit including the forward integrated electronics subsection (FIES) and the power and control subsection (PCS);

Fig. 13 is a side elevational view of the FIES subsection; Fig. 14 is a sectional view of the rear portion of the GNC unit including the PCS subsection the guidance electronics unit (GEU) and the battery;

Fig. 15 is a sectional view of the rear portion of the GNC unit including the GEU and battery;

Fig. 15a is a functional diagram of the GNC unit; Fig. 16 is a perspective sectional view of the bearing assembly;

Fig. 17 is a sectional view of a portion of the bearing assembly including the battery retainer.

Fig. 18 is a sectional view of the GNC unit with the battery installed; DETAILED DESCRIPTION OF THE DRAWINGS

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 Fig. IA, the first round 10 is a 155 millimeter round as utilized by the U.S. Army. The second exemplary round 10 in Fig. IB is a U.S. Navy 155 millimeter round. The third exemplary round in Fig. 1C is a U.S. Navy 5 inch round. Finally, the fourth exemplary round in Fig. ID is a 105 millimeter artillery round as utilized by U.S. Forces. As noted, each of the exemplary rounds 10 employs the GNC unit 12. Significantly, by miniaturizing the GNC unit 12, the 105 millimeter round for the first time is able to be controlled in flight.

The topmost exemplary round 10 in the depiction of Fig. IA is further depicted in Figs. 3-4. The round 10 includes the GNC unit 12. The round 10 additionally is comprised generally of a casing 14, a warhead 16, a rocket motor 18, a rocket nozzle 20, and rear stabilizers 22. It should be noted that the casing 14 has a relatively small thickness dimension 15. The thickness 15 of the casing 14 is able to be reduced by minimizing the mass of the miniaturized GNC unit 12 as compared to prior art GNC units. Such reduced thickness 15 permits the use of a larger rocket motor 18 having more energy to propel the round 10. This is done without compromising the size of the warhead 16. It should be noted in Fig. 4 that the rocket motor 18 has been extended out the nozzle 20.

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 shiftably mounted to the round 10 by means of hinges 24. In the depictions of Figs. IA-D the rear stabilizers 22 are depicted in their deployed disposition. Such deployment takes place after the round 10 has been fired. In transport and prior to firing, the rear stabilizers 22 are pivoted on the hinges 24 into a flush disposition with the exterior margin of the casing 14. Referring to Figs. 2A-C and Fig. 6, the GNC unit 10 may be conveniently broken down into a number of subsections. Proceeding from the nose of the GNC unit 12, the first subsection is the forward integrated electronics subsection ("FIES") 30. The FIES 30 provides the fusing for the round 10. Accordingly, a wire harness 32 provides for communication between the FIES 30 and the fuse, safe, and arm ("FSA") communications device 40 disposed that the rear of the GNC unit is provided.

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 Fig. 5, the FIES 30 includes a height of burst sensor 160 coupled to a height of burst interface 162. The height of burst interface 162 is communicatively coupled to the sensor card 164. A magnetic core 166 substantially surrounds a telemetry unit 168. Rearward in the FIES 30 are output electronics 170 that are coupled to the wire harness 32. At least the forward portion of the outer margin of the FIES 30 is a radome 172.

The GTAU 34, as depicted in Fig. 7, is formed in a generally truncated conical shape having openings defined at both the forward end and the rearward end. A conical interior space 50 is defined within the GTAU 34. A pair of opposed canard slots 52 are defined in the GTAU 34. The antenna material forming the GTAU 34 is preferably formed on the exterior margin of the PCS skin 54. At least the GPS system of satellites communicates with the GNC unit 12 by means of the GTAU 34. Telemetry of the GNC unit 12 may also communicate via the GTAU 34.

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 Fig. 8, the PCS 36 includes an interior housing 58, disposable within the conical interior space 55 defined within the skin 54. A mission power subsystem 59 is disposable within the interior housing 58. Additionally, a keep-alive power source 60 comprising supercapacitors, is also disposable within the interior housing 58. Lastly, the canard actuation subsystem 61 is also disposable within the interior housing 58 of the PCS 36.

The canard actuation subsystem 61 is depicted in Fig. 8 A. Canard actuation subsystem 61 includes a motor 62 that is preferably an electric motor. The output of the motor 62 is a rotatable, toothed output gear 63. The teeth of the output gear 63 are meshed with the teeth of a spur gear 64. Spur gear 64 is coupled to an elongated ball screw 65. A ball screw nut 66 is translatably disposed on the ball screw 65. The rotation of the ball screw 65 causes the ball screw nut 66 to translate longitudinally on the ball screw 65. 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 Fig. 6) of the GNC unit 12. 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 Figs. 9-13, a plurality of antenna connection ports 70 are defined in the skin 54. Such ports 70 provide for communication to the GTAU 34. A plurality of threads 72 are defined on the outer margin of the rear most portion of the skin 54 for coupling to an inner spindle 104, described in detail below. An interfacing diameter 74 is defined at the forward end of the skin 54 for coupling to the FIES 30. A plurality of threaded bores 76 are defined through the interfacing diameter 74. An aperture 78 is defined in the leading face 80 of the skin 54 for providing communication from the FIES 30.

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 Fig. 11, has a plurality of notches 91 defined in the rearward directed margin thereof. Such notches may be grasped by a tool when seating the PCS retaining ring 90. The outer margin of the PCS retaining ring 90 has threads 92 defined thereon for mating with the PCS retaining ring threads 88. Referring to Figs. 12 and 13, representative FIES electronics 94 are depicted abutting the leading face 80 of the PCS skin 54. The FIES housing 96 is generally conical in shape having a rounded leading edge. Proximate the rear margin of the FIES housing 96, a plurality of circumferentially spaced fastener bores 98 are defined in the housing 96. Such bores 98 are brought into registry with the threaded bores 76 of the PCS skin 54 when attaching the FIES 30 to the PCS skin 54. Suitable fasteners are then passed through the bores 98 and threaded into the threaded bores 76.

Moving rearward on the GNC unit 12, as depicted in Figs. 14 and 15, the PCS 36 is seen mated to the portion of the GNC unit 12 containing the GEU 38 and the battery 42. The GEU 38 is effectively a microprocessor. The GEU 38 acts to process inputs and to generate outputs as noted in Fig. 15a. The microprocessor resides in a space defined in a GEU housing 86. The GEU housing 86 is retained within a space defined within an inner spindle 104, described in greater detail below. See Fig. 15.

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 Figs 14 and 15, the PCS retaining ring 90 is threadedly engaged with the inner margin of the PCS skin 54. In this disposition, the PCS retaining ring 90 retains the PCS 36 within the PCS skin 54.

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 1 12a, 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 128 a, 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 Figs. 14 and 16, the inner spindle 104 is threadedly engaged to the PCS skin 54 by means of threads 150 formed proximate the forward margin of the inner spindle 104 engaging the threads 72 defined proximate the rearward margin of the PCS skin 54. The GEU

38 is maintained in position by mate surface 154 and by abutting the forward margin of the mating ring 152.

As depicted in Figs. 17 and 18, the FSA communication board 40 and the battery 42 is retained in place within a mating bore 158 by a battery retaining ring 155. The battery retaining ring 155 has threads 156 defined on the outer margin thereof. The threads 156 engage threads 157 defined by the inner margin of the inner spindle 104. The battery retaining ring 155 is threaded into the inner spindle 104 until the forward margin of the battery retaining ring 155 abuts the mating surface 159.

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 fusing 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 Fig. 15a. During initial portions of the flight, the canards 69 are preferably maintained in a neutral or slightly destabilizing disposition. Such disposition holds the canard 69 at substantially 0 degrees angle of attack. When a course correction of the round 10 is desired, the two canards 69 are oppositely deflected by the respective canard actuation subsystems 61. Such actuation causes the GNC unit 12 to assume a desired rotational disposition relative to the longitudinal axis 46 of the GNC unit 12.

To effect the desired course correction, the two canards 69 are simultaneously rotated by the respective canard actuation subsystems 61. Such rotation is about the axis 57 and results in the two canards 69 having the same angle of attack.

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.

Claims

CLAIMS What is claimed:

1. A guidance and control unit assembly for use with a munitions projectile, the guidance and control unit being roll isolated with respect to the munitions projectile such that roll of the munitions projectile about a projectile longitudinal axis, such roll being imparted to the munitions projectile during the act of launching the munitions projectile, may not be imparted to the guidance and control unit as desired.

2. The guidance and control unit assembly of claim 1 including imparting control to the munitions projectile by no more than a pair of opposed, deployable canards.

3. The guidance and control unit assembly of claim 1 , including a pair of opposed canards being deployable for effecting roll stabilization of a guidance and control unit member.

4. The guidance and control unit assembly of claim 1, including a first spindle and a second spaced apart spindle.

5. The guidance and control unit assembly of claim 1 having a first spindle and a second spaced apart spindle and bearing means interposed between the first and second spindles.

6. The guidance and control unit assembly of claim 5, the bearing means including at least two bearing units.

7. The guidance and control unit assembly of claim 6 wherein the two bearing units are disposed substantially adjacent one another.

8. The guidance and control unit assembly of claim 6 wherein the two bearing units each include an outer ring and a spaced apart inner ring.

9. The guidance and control unit assembly of claim 6 wherein a plurality of roller bearings are captured between a respective outer ring and a corresponding inner ring.

10. The guidance and control unit assembly of claim 1 having a total weight of less than 22.0 lbs.

11. The guidance and control unit assembly of claim 1 having a total weight of less than 13.2 lbs.

12. The guidance and control unit assembly of claim 1 having a total volume that is less than 100.0 cubic inches.

13. The guidance and control unit assembly of claim 1 having a total volume that is less than 87.0 cubic inches.

14. A munitions projectile assembly having a selectively couplable guidance and control unit assembly, a guidance and control unit of the guidance and control unit assembly being roll isolated with respect to a munitions projectile subassembly when coupled to the munitions projectile subassembly such that roll of the munitions projectile subassembly about a projectile longitudinal axis, such roll being imparted to the munitions projectile during the act of launching the munitions projectile, may not be imparted to the guidance and control unit as desired.