GB2459526A

GB2459526A - Protection from attack

Info

Publication number: GB2459526A
Application number: GB9504606A
Authority: GB
Inventors: Gerard Meili; Jean-Marc Besson
Original assignee: POURDES ET EXPLOSIFS SOC NAT D
Current assignee: POURDES ET EXPLOSIFS SOC NAT D
Priority date: 1994-03-15
Filing date: 1995-03-08
Publication date: 2009-11-04
Anticipated expiration: 2015-03-08
Also published as: FR2930984A1; GB2459526B; DE19507709A1; GB9504606D0

Abstract

A platform (P) under attack by an opposing threat (M), for example a missile with a homing head or a projectile guided by fire control, is protected by the deployment of at least one substance forming a screen (E) between the platform (P) and the threat (M), and by placing at least one emissive element (W) between the threat (M) and the screen (E), this emissive element emitting radiation in the visible and/or infrared or as radar.

Description

PROTECTION FRON ATTACK

This invention relates to a method of protection against attack and to a munition useful in the method.

In the event of an attack, countermeasures need to be taken. For example, when a target is attacked by an opposing threat, for example a missile guided by a homing head or a munition directed by fire control, protection is often achieved by causing the device steering the threat to take it away from the target. The opposing threat may be directed automatically towards the target by means of an infrared or radar homing head, or equally this threat may be directed towards the target by direct vision, by a camera or by laser designation of the platform.

The target may be anything: for example it may be land-based, naval or airborne; it may be static, for example a land-based installation, or it may be mobile such as an arnioured vehicle, a ship or an aircraft. Hereinafter the term "platform" is used to mean all targets.

It is known to protect a platform, attacked by a threat such as a missile, by deploying a screen between the platform and the threat. This screen acts in the visible or infrared spectrum, or in the radar region (millimetric to metric waves), sometimes with overlap between these various regions, especially between the visible and infrared. The screen either absorbs the radiation which the homing head of the threat should detect, or it reflects the radiation emitted in order to guide the threat, so that the threat no longer receives a useful signal for guiding it. In other words, the threat no longer "sees" the platform and can no longer be directed towards it.

The protection screen is usually deployed either by the combustion of smoke-generating pyrotechnic substances, or by the dispersion of mineral or organic substances of suitable type, form and dimensions. The dispersion of the substances forming the screen may take place in different ways, for example by pneumatic means or pyrotechnic means.

Such protection screens are essentially a cloud of particles and of gas deployed around the platform or at a certain distance from it.

The effectiveness of a cloud of particles forming a screen can be evaluated on the basis of the geometry of the cloud. The thickness and concentration of particles in the cloud are important, as are various coefficients intrinsic to the particles, particularly their mass extinction coefficient.

One problem with known screens is that they are not always as effective as would be desired, particularly in terms of increasing the confusion of the threat when the platform is masked by the screen and when the threat no longer sees this platform. However, whilst very effective screening is highly desirable, it brings with it the problem that, if the screen masks the threat very efficiently and renders the threat inoperative, reciprocally., the threat is masked for the platform. Thus, the platform-cannot attack the threat and, if a mobile platform is involved, it may be.

impeded in its manoeuvres for escaping from the threat.

We have now devised a method and munitioriby which this problem can be reduced or overcome.

According to the present invention, there is provided a method of protecting a platform attacked by a threat, the method comprising the deployment of at least one substance forming a screen between the platform and the threat, characterised in that at least one emissive element is put in place between the threat and the screen.

Advantageously, one of the substances deployed in order to form the screen is reflecting for the radiation of the emissive element.

The invention also provides a munition for use in protecting a platform against attack by a threat, which munition comprises a device for deploying at least one substance to form a screen between the platform and the threat, and a system for placing at least one emissive element between the threat and the screen. This munition may be in the form of a single object or of two separate submuni tions.

The present invention reduces or overcomes the problems of the prior art by persistently dazzling the guidance device of the threat, and thus increasing its confusion, and by simultaneously allowing the platform to detect the threat, through the screen, in order to counterattack it or in order to steer itself in its manoeuvre so as to shake off the threat.

A detailed description of an example of the

invention will now be given, in relation to the protection of a platform attacked by an opposing threat, for example a missile with a homing head or a projectile guided by fire control. In this example, the emissive element emits radiation in the visible and/or infrared, or as radar.

The screen is preferably formed around or at up to a few tens of metres from the platform, by dispersing substances forming a cloud of particles and of gas, preferably by pneumatic and/or pyrotechnic means. The substances used are, for example, in the visible spectrum and in the infrared spectrum, metal chaff of a few micrometres in width and of a few tenths of micrometres in thickness. The particles can be dispersed from canisters which may be projected towards the threat by launch systems placed on, or in proximity to, the platform to be protected.

The dispersion takes place during the ballistic flight of the canister, or when the canister has fallen back onto the ground, at a distance from the platform.

The emissive element is placed between the threat and the screen by use of a launch system which a person skilled in the art will know how to achieve. This emissive element must then be held in this position for a sufficient time. For example, either the emissive element will rest on the ground or, if it remains in the air, its fall will be slowed by appropriate devices, such as parachutes. A single emissive element may be used, the operating duration of which is long, for example from 60 to 90 seconds. A plurality (two or more) of such emissive elements may alternatively be used in order to create several emissive sources between the threat and the screen. Several emissive elements may also be envisaged operating in cascade, that is to say in such a way as continuously to have at least one emissive element in activity between the threat and the screen, over a duration of 60 to 90 seconds, or longer.

The emissive element placed between the threat and the screen produces visible and/or infrared radiation, for example. Some of this radiation directly illuminates the threat, another part is diffused towards the threat by the screen. The diffused radiation is the radiation deflected by the particles forming the screen in various directions.

All this radiation which illuminates the threat, on the one hand, dazzles the homing head or the fire control of the threat and, on the other hand, increases the contrast of the threat, that is to say increases the view which the platform has of the threat.

Advantageously, at least one of the substances deployed to form the screen is reflecting for the radiation of the emissive element. By reflecting is meant here that the substance, illuminated by an incident radiation, will strongly diffuse this radiation in a direction substantially opposite to the incident direction. This effect is obtained either by the same substance as that used to form the screen, or by the addition to this substance of material with a high diffusion power with respect to the radiation of the emissive element. The diffusion power is the ability of the substance to deflect part of the incident radiation in different directions to that of the incident radiation.

In a particular implementation of the method of the invention, at least one emissive element is placed in the screen, that is to say in the cloud of particles formed by the dispersion of the substance provided for this purpose. More precisely, this emissive element is placed along the edges of the screen cloud, on the same side as the threat. This particular arrangement of at least one emissive element increases the diffusion of the radiation emitted by the emissive element towards the threat.

In this method, when the screen deployed between the platform and the threat comprises one or more substances which are absorbing in the visible or infrared, the emissive element radiates in the visible or infrared. In contrast, if the substance forming the screen has a wider spectral absorption which covers both the visible and the infrared (or a part of the latter), then the emissive element will radiate in the visible and in the infrared.

Advantageously, the screen comprises at least one substance with a high diffusion power in the visible or infrared, or in a widened spectral domain of visible and infrared, according to whether the screen is absorbing in the visible or the infrared, or also in a widened spectral domain comprising both visible and infrared.

Preferably, in the method according to the invention, the radiation of the emissive element is produced by the combustion of a pyrotechnic mixture. This pyrotechnic mixture can include, for example, a binder which coats or agglomerates an oxidizing charge, at least one reducing charge such as magnesium or aluminium and possibly various known additives, and especially additives for increasing the radiation or adjusting the spectral domain.

This pyrotechnic mixture burns in a suitable support, and its combustion is initiated by electropyromechanical means during the operating sequence of the system able to place the emissive elements.

The munitions of the invention comprise a device able to deploy at least one substance to form a screen between the platform and the threat, and a system able to place at least one emissive element between the threat and the screen. This emissive element emits suitable radiation.

There may be a plurality of emissive elements such as those previously mentioned, creating several emissive sources between the threat and the screen. It is also possible to adapt several emissive elements operating in cascade, that is to say in such a way as continuously to have at least one emissive element in activity between the threat and the screen, over a duration of 60 to 90 seconds.

and even a greater duration.

Advantageously, the device able for deploying the substance or substances in order to form the screen between the platform and the threat includes at least one substance which is reflecting for the radiation of the einissive element. This substance may be the same as that intended to form the screen or this may be the addition of another substance of a high diffusing power with respect to the radiation of the emissive element.

In a first embodiment, the munition comprises two separate submunitions, one including the device for deploying at least one substance forming the screen, the other the system for placing at least one emissive element between the threat and the screen.

These two submunitions are put into use according to a predetermined sequence. Extraction or launch means direct the two to submunitions towards the threat and, with suitable time delays, trigger the device able to form the screen; this device deploys the substance forming the screen. at the desired distance, and the system able to place the emissive elements which are placed and activated between the threat and the screen. These extraction or launch means are, in general, electrically initiated pyromechanical means. With the aid of suitable time-delayed pyrotechnic relays, these means activate the device for forming the screen and the system for putting the emissive elements in place.

In a second embodiment, the munition consists of a single carrier vehicle including a device for deploying the substance forming the screen, and a system for placing the emissive elements between the threat and the screen.

This munition is ejected towards the threat, by a pyromechanical device for example, from a launch tube.

In a first variant, a single disperser system triggers the device for deploying the substance forming the screen at the desired distance from the platform, and activates the system for placing the emissive elements between the screen and the threat: this latter phase includes ejecting the emissive elements towards their final position and also setting them into operation.

The disperser system, pyrotechnic in general, is itself initiated by time-delayed pyrotechnic relays, from the pyromechanical ejection device of the carrier vehicle.

In a second variant, the carrier vehicle includes two separate disperser systems, one activating the device for forming the screen, and the other activating the system for placing the emissive elements. These disperser devices are initiated from the pyromechanical ejection device of the carrier vehicle.

In order that the invention may be more fully understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 represents an embodiment of munition according to the invention, in diagrammatic cross-section.

It is of the single carrier vehicle type.

Figure 2 illustrates use of the munition of Figure 1 in operations.

In Figure 1, the munition 1 is shown out of its launch tube. The munition 1 includes a body 2 separated into two parts by a transverse partition 4. The munition is aerodynamically stabilized on its trajectory by fins 3 which are represented in deployed and locked position.

The rear part of the munition contains the device for deploying a screen E (Fig. 2). This device 5 comprises a substance 6, preferably a mixture of substances, as described previously, and a disperser system 10.

The front part of the munition contains the system 7 for placing the emissive elements W. This system comprises emissive elements 8 and a disperser device 11.

The disperser devices 10 and 11 are linked by a relay 13 and they are initiated by a suitable time-delayed relay 12. The pyrotechnic chain consisting of the relays 12 and 13 and the disperser devices 10 and 11 is arranged here along the axis of the munition 1.

The munition 1 is launched from a launch tube which also serves as a storage tube. This tube is, in general, arranged on the platform to be protected. The launching of this munition, from the launch tube, is done by a pyromechanical system initiated electrically from the command post of the platform. The operation of this pyromechanical device will also, via the relays 12 and 13, initiate the operation respectively of the device 5 able to create a screen E and of the system 7 able to place the emissive elements 8. The time delay adopted for these relays 12 and 13 is that which initiates the disperser devices 10 and 11 so that the screen E is formed and the emissive elements are placed at the required points of the trajectory, taking account of launch parameters, especially the launch impulse and the inclination of the said munition.

The operation of the disperser system 10 will deploy the substance 6 in order to create the screen E. The deployment may be a simple dispersion, by a disperser device such as an explosive bar, of the substance 6 which is of the brass chaff type for example. Deployment may also be achieved by combustion of a smoke-generating product, the substance 6 then comprising oxidizing and reducing charges with carbon-chain products and possibly phosphorus.

The operation of the disperser device 11 will disperse the emissive elements 8. The emissive elements 8 here are cakes of pyrotechnic substances, the combustion of which is triggered from the disperser system 11. The dimension and the shape of these cakes is designed to ensure a long operating duration of 30 s to more than 90 s. The pyrotechnic substance used comprises phosphorus, iron oxide, or magnesium or ammonium nitrate, for example. The cakes are suspended from devices which slow their fall. With these illuminating elements remaining in front of the screen E in this prolonged way, their effectiveness is increased.

Figure 2 illustrates the application of the present invention, on the site of operations, to the protection of a tank P threatened, at M2, by an infantryman carrying an anti-tank weapon or, at Ml, by a missile-launcher helicopter; in a more general way, the threat will be called threat M. From a mortar placed on the tank, a munition 1 (or a salvo of these munitions) is ejected. This diagram shows a munition 1 on its trajectory, and also the effects of a munition which has functioned. The latter munition has created a screen E, at a few tens of metres from the tank P and in the direction of the threat M; emissive elements W are falling, slowed by their retardation system in front of or along the edges of the screen E, between this screen and the threat M. The direct radiation from these emissive elements W towards the threat M dazzles this threat. This direct radiation is shown diagrammatically in Figure 2 by arrows directed from the emissive elements W towards the -10 -threat M. The radiation reflected by the screen E is also increasing this effect of dazzling the threat, and it contributes to the confusion of the threat. In a similar way to the foregoing, the reflected radiation is shown diagrammatically by the "arrows" coming from the emissive elements W and being reflected on the screen E. For clarity in the figures, the devices which are slowing the descent of the emissive elements W are not shown.

In contrast, the platform P (a tank) for which the threat was also masked by the screen E, will again detect the threat H, since the latter, illuminated by the emissive elements, has its contrast increased by the radiation of the emissive elements W. The screen E according to the invention is a one-way vision screen: for the threat M it is opaque and dazzling, the threat no longer sees the platform, its target. In contrast, for the tank P, it remains transparent: the tank P follows the movements of the threat H and can attack it effectively or slip away without leaving itself uncovered by the screen E.

Claims

CLAIMS: 1. A method of protecting a platform from attack by a threat, which method comprises deploying at least one substance to form a screen between the platform and the threat, arid putting in place at least one emissive element between the threat and the screen.
2. A method according to claim 1, wherein at least one of the substances deployed to form the screen is reflecting for the radiation of the emissive element.
3. A method according to claim 1 or 2, wherein at least one emissive element is placed in the screen, along the edges of the latter, on the same side as the threat.
4. A method according to claim 1, 2 or 3, wherein the screen comprises substances which are absorbing in the visible and/or the infrared spectrum, and the emissive element radiates in the same spectral region.
5. A method according to claim 4. wherein at least one of the substances forming the screen is reflecting for the visible and/or infrared.
6. A nethod according to claim 4 or 5, wherein the radiation of the emissive element is produced by the combustion of a pyrotechnic mixture.
7. A munition for use in protecting a platform against attack by a threat, which munition comprises a device for deploying at least one substance to form a screen between the platform and the threat, and a system for placing at least one emissive element between the threat and the screen.
8. A munition according to claim 7, wherein at least one of the substances for forming the screen is reflecting for the radiation of the emissive element.
9. A munition according to claim 7 or 8, which comprises two separate submunitions, one including the device for deploying at least one substance to form a screen, and the other including the system for placing at least one emissive element between the threat and the screen.
10. A munition according to claim 7 or 8, which comprises a single carrier vehicle including the device for deploying the substance for forming the screen, and the system for placing at least one emissive element between the threat and the screen.
11. A method of protecting a platform from attack wherein there is used a munition as claimed in any of claims 7 to 10.
12. A method of protecting a platform from attack by a threat, substantially as herein described with reference to Figure 2 of the accompanying drawing.
13. A munition for use in protecting a platform against attack, substantially as herein described with reference to Figure 1 of the accompanying drawing.Amendments to the claims have been filed as follows 1. A method of protecting a platform from attack by a threat which method comprises deploying at least one substance to form a screen between the platform and the threat, and putting in place at least one emissive element in the screen along the edges thereof on the same side as the threat, or between the threat and the screen, and wherein at least one of the substances deployed to form the screen is reflecting for the radiation of the emissive element.2. A method according to claim 1, wherein at least one of the substances forming the screen is reflecting for the visible and/or infrared.3. A method according to claim 2, wherein the at least one substance forming the screen is metal particles of a few micrometers in width and of a few tenths of micrometers in thickness.4. A method according to claim 1,2 or 3, wherein the radiation of the emissive element is produced by the combustion of a pyrotechnic mixture.5. A munition for use in protecting a platform against attack by a threat, which munition comprises a device for deploying at least one substance to form a screen between the platform and the threat, and a system for placing at least one emissive element in the screen along the edges thereof on the same side as the threat, or between the threat and the screen, and wherein at least one of the substances for forming the screen is reflecting for the radiation of the emissive element.IL6. A munition according to claim 5, which comprises two separate submunitions, one including the device for deploying at least one substance to form a screen, and the other including the system for placing at least one emissive element in the screen or between the threat and the screen.7. A munition according to claim 5, which comprises a single carrier vehicle including the device for deploying the substance for forming the screen, and the system for placing at least one emissive element between the threat and the screen.8. A method of protecting a platform from attack wherein there is used a munition as claimed in any of claims 5 to 7.9. A method of protecting a platform from attack by a threat, substantially as herein described with reference to Figure 2 of the accompanying drawing.10. A munition for use in protecting a platform against attack, substantially as herein described with reference to Figure 1 of the accompanying drawing.