GB2251834A

GB2251834A - Guided missiles and like devices

Info

Publication number: GB2251834A
Application number: GB8304925A
Authority: GB
Inventors: George Alexander Tarrant
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-02-22
Filing date: 1983-02-22
Publication date: 1992-07-22
Anticipated expiration: 2003-02-22
Also published as: GB2251834B

Abstract

A guided missile or like device having a longitudinal axis has control means comprising a plurality of laterally-directed nozzles for venting a fluid and thereby producing lateral thrusts on said device, said nozzles being disposed in at least two sets spaced apart in a longitudinal direction and being so arranged that said thrusts can control the flight behaviour of said device. The nozzles may be disposed in two planes through said longitudinal axis at right angles to each other or in two parallel planes on opposite sides of said axis. <IMAGE>

Description

TITLE: GUIDED MISSILES AND LIKE DEVICES DESCRIPTION This invention relates to guided missiles and like devices and particularly but not exclusively to missiles of a kind which are suitable for the attack of vehicular ground targets and which employ homing guidance.

Missiles of such a kind typically comprise a device which is sensitive to certain emissions in the EM spectrum which are characteristic of the target and which tracks the said target and determines the rate of rotation of the missile-to-target sightline, a set of fixed external surfaces and a set of movable actuatorcontrolled surfaces to enable the missile to manoeuvre by aerodynamic means and instruments such as gyros and accelerometers to measure its flight behaviour. The whole is assembled in such a way that the missile achieves a guidance accuracy which is sufficiently good for the attack of vehicular ground targets. This type of missile presents disadvantages in the inherent cost of the actuators and instruments and the complexity and cost of a precision gimbal system which may be necessary to determine the rate of rotation of the missile-totarget sightline.It is also unable to operate at low flight speeds where the aerodynamic forces and moments are small.

It is an object of this invention to obviate or reduce these disadvantages and particularly the need for movable external surfaces.

The invention provides control means for a guided missile or like device having a longitudinal axis, said control means comprising a plurality of laterallydirected nozzles for venting a fluid and thereby producing lateral thrusts on said device, said nozzles being disposed in at least two sets spaced apart in a longitudinal direction and being so arranged that said thrusts can control the flight behaviour of said device.

In one form of the invention, said nozzles are disposed in pairs with the two nozzles of each pair in different sets and oppositely and outwardly directed pairs of nozzles are disposed in each of at least two planes through said longitudinal axis at 900 to each other. Thus, the nozzles can produce radial thrusts on the missile, being disposed so that said thrusts or components thereof act in two planes through said longitudinal axis at 900 to each other. The thrusts can thereby produce sideways motion and rotational motion of said longitudinal axis. The particular motion or combination of motions at any given time may be determined by means for controlling the venting of fluid and thereby the magnitude and application of the thrusts.

In another form of the invention, said nozzles are disposed in pairs with the two nozzles of each pair in different sets and oppositely and outwardly directed pairs of nozzles are disposed in each of at least two parallel planes symmetrically spaced from said longitudinal axis. Thus, the thrusts can produce sideways motion and rotational motion of said longitudinal axis and rotational motion about that axis. The particular motion or combination of motions at any given time may be determined by controlling means as aforesaid.

Said control means may be provided in the form of a unit for use in the construction of a guided missile or like device.

The invention further provides a guided missile or like device having an aforesaid control means, in which device said sets are symmetrically spaced apart in a longitudinal direction on opposite sides of the centre of gravity of the device.

The invention also provides a guided missile or like device having an aforesaid control means wherein said nozzles are disposed in pairs with the two nozzles of each pair in different sets, each pair of nozzles being oppositely directed to another pair of nozzles in the same plane, in which device said sets are symmetrically spaced apart in a longitudinal direction on opposite sides of the centre of gravity of the device.

If desired, more than two sets of nozzles may be provided symmetrically arranged on opposite sides of the centre of gravity.

Preferably, there are provided means for controlling the magnitude and application of said thrusts according to the angle between said device and a target.

The invention also provides a method of controlling the flight behaviour of a guided missile or like device having a longitudinal axis, which method comprises venting fluid at a plurality of positions around said device and on opposite sides of the centre of gravity of the device in a longitudinal direction, and controlling said venting to obtain the desired flight behaviour.

In one preferred form of the invention there is provided a missile (fore)body comprising means (e.g. a device which is sensitive to certain emissions in the EM spectrum which are characteristic of the target) which is capable of tracking the said target and continuously determining the angle between the longitudinal axis of the missile and the missile-to-target sightline, means for applying side-thrust to the missile body through a plurality of pairs of nozzles thrusting radially along two planes at 900 to each other and symmetrically disposed about the missile centre-of-gravity in such a way that in each plane equal thrusts from a pair of nozzles in the same direction produce sideways motion (horizontally and/or vertically) of the missile and equal thrusts in opposite directions from two nozzles on opposite sides of the centre-of-gravity in radially opposite pairs produce rotational motion, and means for controlling the magnitude and application of the said thrusts according to the angle between the longitudinal axis of the missile and the missile-to-target sightline.

In this preferred form of the invention; there may alternatively be provided means for applying side-thrust to the missile body through a plurality of pairs of nozzles so arranged that they can provide thrust in parallel planes (instead of two planes at 900 to each other) but now symmetrically disposed about the missile centre-of-gravity in such a way that, in addition to providing sideways and rotational motion of the longitudinal axis of the missile in that plane, they can also provide rotational motion about the longitudinal axis, as hereinbefore discussed.

Where both methods of control are concerned, there is also the possibility of setting any number of the nozzles at such an angle that, in addition to providing the sideways and rotational motion described above, they also provide a net component of thrust along the longitudinal axis of the missile.

Preferably the means for determining the angle between the missile body and the missile-to-target sightline will have the ability to track targets several degrees off-axis (e.g. 40) and will provide measurements many times per second (e.g. 10-20).

Preferably the means for controlling the magnitude and application of the said thrusts will include the ability to cause the missile to execute angular oscillations (conical) about its centre of gravity.

Preferably the thrusts will be developed by venting the hot gaseous products from the combustion of a pyrotechnic (e.g. cordite) charge in a combustion chamber.

Preferably also the average thrust levels produced will be in linear proportion to an electrical input signal.

Embodiments of the invention having four pairs of nozzles will now be described by way of example with reference to the accompanying schematic drawings, in which Fig. 1 is a longitudinal section of a guided missile having one embodiment of control means, combined with a diagram of a controlling circuit for said control means, Fig. 2 is a cross-section through one set of nozzles of the missile of Fig. 1, Figs. 3 and 4 are side views of a guided missile having another embodiment of control means, and Fig. 5 is a cross-section on lines A-A' of Fig. 3.

Referring to Figs. 1 and 2, a missile suitable for the attack of vehicular ground targets comprises a seeker unit 1 for determining the angle between the longitudinal axis X of the missile and the missile-totarget sightline, a thruster unit 2 with four pairs of nozzles 2a, one nozzle of each pair being equidistantly spaced on each side of the centre of gravity G and the pairs lying in two planes at 900 to each other through said longitudinal axis, for controlling the motion of the missile by venting gas and a volume 3 which contains power supplies for the seeker unit 1 and the thruster unit 2 and remaining missile components. The seeker unit also contains the electronic means of controlling the magnitude and application of the side-thrusts.

The following description with regard to Figs. 1 and 2 relates to the principles of operation in one plane through the longitudinal axis; the same 0 principles apply in the plane at 90 and when the two planes operate together the missile is able to manoeuvre three-dimensionally.

The seeker unit 1 tracks a target and determines the angle between the longitudinal axis of the missile and the missile-to-target sightline Y (designated boresight error). This boresight error signal is fed to an electrical gain and compensation network 4 to form an electrical signal proportional to a differential thrust command ( gT) and to an electrical gain and integrator network 5 to form an electrical signal proportional to side-thrust command (T). These electrical signals are then summed in circuit 6 and differenced in circuit 7 to produce electrical commands to the fore and aft sets of thruster nozzles respectively as follows. (These functions may be performed in the seeker unit).Through the combined action of the electrical input signals and a sawtooth carrier wave from generator 8 solenoid drivers 9, 10 produce variable pulse-width square wave signals to which solenoids 11, 12 respond. The resulting solenoid motion produces mean thrust levels which are proportional to the respective demands and the resultant of these mean thrust levels is a thrust T acting through the centre of gravity and a torque acting about it proportional to ST.

After the missile has been released from the releasing vehicle, power supplies (located in the volume 3) are activated and the seeker unit 1 searches for a target within its field of view. If no target is immediately visible the missile executes a conical scan about its centre of gravity to widen the field of search.

When a target has been acquired the seeker unit 1 tracks the said target and begins to issue boresight error signals. These are transformed by the electrical circuits 4, 5, 6, 7 into commands for thrust which is in turn developed by the action of the solenoids 11, 12 on the fore and aft thruster nozzles. The resulting sidethrust and torque causes translational and rotational motion respectively of the missile and this is sensed by the seeker unit 1 and used to generate further bore sight error signals. This process whereby the seeker unit 1 applies quasi-continuous corrections to the missile motion continues until the missile reaches the target.

Referring to Figs. 3, 4 and 5, the embodiment shown employs four pairs of nozzles 2a arranged in two parallel planes equidistantly spaced on opposite sides of the longitudinal axis X of the missile. The nozzles are also arranged in two sets symmetrically spaced along said axis on opposite sides of the centre of gravity of the missile. The arrows in these Figures indicate the direction of thrusts generated by venting gas from appropriate nozzles so that there is sideways motion of the longitudinal axis in Fig. 3, rotational movement of the longitudinal axis in Fig. 4, and rotational movement about the longitudinal axis in Fig. 5.When used with this method of control, the seeker unit would determine the total angle between the longitudinal axis of the missile and the missile-to-target sightline (rather than two components at 900) and the direction of that angle with respect to the common plane of action of the thruster unit.

In the embodiment of Figs. 3 to 5, to improve the control, the nozzles (instead of being directed in the planes in which they lie) may be directed at an angle to those planes and away from the common plane through the longitudinal axis between and parallel to the aforesaid planes. Alternatively or additionally two oppositely directed pairs of radially-directed nozzles may be provided in a plane through said axis and at right angles to the aforesaid planes.

The present invention may for example be applied to guided missiles which are launched without carrying means of propulsion, to guided missiles which are launched carrying a fuelled propulsion unit (in which case the references hereinbefore to "centre of gravity" apply to the missile after the fuel in the propulsion unit has been exhausted or after the propulsion unit has been detached), and to shells and other projectiles, and all such items fall within the scope of the expression "guided missiles and like devices".

Claims

CLAIMS 1. Control means for a guided missile or like device having a longitudinal axis, said control means comprising a plurality of laterally-directed nozzles for venting a fluid and thereby producing lateral thrusts on said device, said nozzles being disposed in at, least two sets spaced apart in a longitudinal direction and being so arranged that said thrusts can control the flight behaviour of said device. 2. Control means according to claim 1 wherein said nozzles are disposed in pairs with the two nozzles of each pair in different sets and oppositely and outwardly directed pairs of nozzles are disposed in each of at least two planes through said longitudinal axis at 900 to each other. 3. Control means according to claim 1 wherein said nozzles are disposed in pairs with the two nozzles of each pair in different sets and oppositely and outwardly directed pairs of nozzles are disposed in each of at least two parallel planes symmetrically spaced from said longitudinal axis. 4. A guided missile or like device having control means according to claim 1, 2 or 3 in which device said sets are symmetrically spaced apart in a longitudinal direction on opposite sides of the centre of gravity of the device. 5. A guided missile or like device according to claim 4 having means for controlling the magnitude and application of said thrusts according to the angle between the longitudinal axis of said device and a target. 6. A method of controlling the flight behaviour of a guided missile or like device having a longitudinal axis, which method comprises venting fluid in a lateral direction at a plurality of positions around said device and on opposite sides of the centre of gravity of the device in a longitudinal direction, and controlling said venting to obtain the desired flight behaviour. Amendments to the claims have been filed as follows

1. A guided missile having a central axis and flight control means comprising a plurality of nozzles directed laterally and outwardly with respect to said axis for venting a fluid and thereby producing lateral thrusts on the missile, a set of said nozzles being spaced around the periphery of the missile in each of at least two planes which are normal to said axis and are symmetrically spaced apart on opposite sides of the centre of gravity of the missile and said nozzles also being disposed in pairs with the two nozzles of each pair lying on a common line parallel to said axis and comprising a nozzle in one of said sets and a nozzle in the other of said sets, means for continually tracking a target and determining the angle between said axis and a line between the missile and the target, and means conditioned by said tracking means for continually controlling the venting of gases selectively from nozzles in the different pairs and the different sets according to said angle whereby said axis can be moved translationally and rotationally to follow the target.

2. A guided missile according to claim 1 wherein two oppositely directed pairs of nozzles are disposed in each of at least two planes through said axis at 900 to each other.

3. A guided missile according to claim 1 wherein two oppositely directed pairs of nozzles are disposed in each of at least two parallel planes symmetrically spaced apart on opposite sides of and parallel to said axis whereby the missile can also be moved rotationally about said axis.

4. A guided missile according to claim 2 wherein the nozzles are directed in said two planes at 900 to each other.

5. A guided missile according to claim 3 wherein the nozzles are directed in said two parallel planes.

6. A guided missile according to claim 3- wherein the nozzles are directed at angles to said two parallel planes and away from a plane which is parallel to said two parallel planes and passes through said axis.

7. A guided missile according to claim 3, 5 or 6 wherein two oppositely directed pairs of radially-directed nozzles may be provided in a plane through said axis at right angles to said two parallel planes.

8. A guided missile according to any preceding claim wherein at least some of the nozzles are directed at such an angle that they provide a net component of thrust along said axis.

9. A guided missile substantially as hereinbefore described with reference to the accompanying drawings.