GB2521095A

GB2521095A - Infrared decoy and a method for deployment thereof

Info

Publication number: GB2521095A
Application number: GB9919616.4A
Authority: GB
Inventors: Gerhard Winterling
Original assignee: DaimlerChrysler Aerospace AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1998-08-18
Filing date: 1999-08-17
Publication date: 2015-06-17
Anticipated expiration: 2019-08-17
Also published as: DE19837330B3; ITRM990526A1; GB2521095B; GB199919616D0; GB199918442D0

Abstract

IR decoy for use on an aircraft for deceiving incoming missiles having IR target homing heads. The IR decoy emitting IR radiation in the spectral band which is relevant for the IR target homing heads, and being deployed using a towing cable from a launcher which is fitted to the aircraft. The IR radiation from the decoy being produced on the side facing away from the aircraft (31) and the IR decoy (1) having aerodynamic braking means such as air-brakes or flaps (10) which reduce the local air flow velocity in the area of the IR radiation emitter. A method being provided also for deploying the IR decoy from the aircraft as a function of the aspect angle.

Description

Infrared decoy and a method for deployment thereof.

This invention relates to an infrared (IR) decoy for protecting military aircraft against threats by missiles having IR target homing heads, and to a method for deploying such JR decoys from the threatened aircraft.

IR decoys or flares are normally fired from launchers or dispensers which are fitted to military aircraft, in order to protect them against the threat from IR-guided missiles. The conventional modern IR decoys and the normal measures for their deployment are, however, no longer effective against relatively modern IR-guided missiles, since relatively modem IR-target homing heads assume that JR decoys will be ejected and thus they can be detected on the basis of the different characteristics between the lR decoys and the aircraft. In this way homing heads can discriminate said decoys as a false target. In order to prevent lR target homing heads from being able to identify decoys on the basis of the various sightline spin rates of decoys and aircraft, at which such decoys appear for IR target homing heads depending on their relative position, IR decoys are towed by a cable behind the aircraft, so that their kinematic response is similar to that of the aircraft, and they can no longer be detected on the basis of a comparison of the sightline spin rates.

Such a towed IR decoy is disclosed in Japanese Patent Specification JP 1-203 899. A disadvantage of this towed decoy is that the design is extremely complex owing mainly to the use of a plurality of Luneberg lenses and thus the device cannot be accommodated in conventional launchers and deployed from them. A further disadvantage of this towed decoy is that the distance between the threatened aircraft and the IR decoy being towed cannot be varied sufficiently quickly as soon as a threat approaches. There is thus a risk of the threat detonating in the vicinity of the aircraft to be protected.

DE-A 23 57 769 discloses a method for deploying a towed decoy, in which the distance between the aircraft and the towed decoy can also be varied. However, this method has the disadvantage that, at the time when the decoy activates, it may still have a relatively high relative speed with respect to the towing aircraft, so that the decoy can be identified as such by a homing head and no longer provides effective decoy effect.

A further method for deploying a decoy is disclosed in DE-B 19543489. In this case, the ejected decoy initially remains connected to the launcher, and thus to the aircraft, by means of a towline for a relatively short time. During this time, the length of the towline increases relatively slowly in comparison with the aircraft speed, with the paying-out rate of the towline being adjustable. After a certain time, the towline is cut, and the burning decoy is released. In the subject matter of DE-B 195 43 489, the decoy, on deployment, can admittedly no longer be identified as a false target by a target homing head (at least in the initial phase of the deployment process) on the basis of the kinematic response of the decoy.

However, relatively modern IR target homing heads can distinguish between the decoy and the aircraft, and thus identify them, since such decoys do not simulate the IR signature of aircraft sufficiently well.

One object of this invention is to provide IR decoys as well as methods for their deployment, in which the protection of a threatened aircraft is also achieved against relatively modern IR target homing heads.

According to this invention there is provided an IR decoy for use on an aircraft for deceiving missiles having lR target homing heads, wherein the IR decoy emits JR radiation in the spectral band which is relevant for the IR target homing heads, the decoy being deployed from a launcher carried by the aircraft and towed by a cable, the IR decoy having braking means and the zone which emits the IR radiation being located behind the said braking means as seen from the aircraft.

According to this invention there is also provided an IR decoy for use on an aircraft for deceiving missiles having IR target homing heads, wherein the lR decoy emits lR radiation in the spectral band which is relevant for the JR target homing heads, the decoy being deployed from a launcher carried by the aircraft and towed by a cable, wherein the rate of paying-out the towing cable is varied controllably as a function of the aspect angle of the incoming missile.

This invention provides also a method for deploying an IR decoy to protect an aircraft against a missile having an JR target homing head, in which the decoy is deployed on a towing cable from the aircraft at a deployment rate which is a function of the aspect angle which is covered by

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the lines of sight originating at the missile to the aircraft and to the IR decoy.

The shaping of the decoy according to this invention and appropriate selection of the installation positions of the material which produces radiation result in the emitted intensity varying to a major extent with the aspect angle with respect to the decoy axis and, in this way, largely simulating the aspect-angle-dependent lR signature of the aircraft to be protected. Furthermore, the shaping prevents the magnitude of the surrounding flow speed of the air around the decoy from being severely degraded. In addition, the selection of the installation positions of the material which produces the radiation results in the spectral variation of the JR aircraft signature as a function of the aspect angle being simulated better, even at a relative high aircraft speed.

The aspect-angle-dependent control of the deployment of the decoy results in the change in the distance between the decoy and the aircraft to be protected on the one hand not being so large at the start of the deployment process that the decoy still remains in the field of view of the target homing head while, on the other hand, the deployment after a certain time is not excessively low, in order to reduce the risk of an enemy explosive warhead being able to detonate in the vicinity of the aircraft to be protected.

The invention is further described and illustrated with reference to the drawings showing an embodiment as an example and wherein: Figure 1 shows diagrammatically an IR decoy according to this invention and as seen in side view, Figure 2 shows a block diagram illustrating the control of the deployment operation1 Figure 3 shows the angular relationships between a threat having an lR target homing head, the aircraft to be protected and the decoy deployed from it, in the horizontal plane, and Figure 4 shows the angular relationships between a threat having an IR target homing head, the aircraft to be protected and a decoy to deployed from it, in the vertical plane.

The IR decoy 1 shown in Figure 1 is kept in the air by means of a towing cable 3, which is attached to the decoy 1 by means of a towing eye 5. The IR decoy 1 has a cylindrical shape and as viewed in the direction of flight and from the aircraft to be protected has, a front fuselage section 7 and a rear fuselage section 8. The front fuselage section 7 has a larger diameter than the rear fuselage section 8, with a geometric junction being located at the point 9, which runs in the circumferential direction, where the front fuselage 7 is joined to the rear fuselage section 8. This geometric junction may be in the form of a step or else an angled surface.

Movable aerodynamic braking flaps 10 (air-brakes) are fitted in the vicinity of the point 9. The braking flaps 10 are pivoted by actuating drives which are not shown, with a central pivoted position being shown in Figure 1.

Stabilization surfaces 11 are filled to the rear section of the rear fuselage section 8, seen in the direction of flight, and move to the position shown after deployment or ejection of the IR decoy from a container, adopting a fixed position with respect to the structure of the towed decoy when it is in the air.

Instead of actuating drives, a spring element arrangement or some other actuating apparatus according to the prior art can also be provided in order to operate the braking flaps 10. When using a spring element arrangement, this is preferably set such that, on the basis of the equilibrium of forces between the spring forces and air forces resulting from the incident-flow velocity, these flaps reach a position in which the deceiving effectiveness that is to be achieved is reached.

In an alternative embodiment, the braking flaps may also be arranged such that they can be extended, in which case the extension capability can also be provided in addition to the pivoting capability of the braking flaps 10. The braking flaps may also be arranged rigidly on the IR decoy 1.

Those surfaces of the lR decoy 1 which produce radiation and, in particular, are combustible, are located behind the braking flaps 10, seen from the towing cable 3, that is to say on that section of the casing surface of the IR decoy 1 which faces away from the aircraft. In contrast, the towing eye 5 for the towing cable 3 is preferably fitted on the front fuselage section 7, the so-called "cold" section of the IR decoy 1.

The intrinsic signature of the aircraft to be protected depends (in the spectral band of the detecting IR target homing head) to a major extent on the aspect angle, that is to say the azimuth angle and the elevation angle, which is to say the angle between the sightline and the aircraft longitudinal axis or aircraft velocity direction. When seen from the front, the lR signature is relatively small but is very large when seen from the rear, to be precise typically greater by a factor of approximately 10 to 20. In addition, the hot engine parts of the aircraft can generally be seen from the rear, so that the spectral distribution of the aircraft signature also generally varies considerably with the aspect angle. In a corresponding manner, the detecting IR target homing head sees the aircraft to be protected as being "colder from the front than from the rear. This requirement is satisfied by the design of the IR decoy 1 according to this invention.

Arranging the hot, burning surfaces, or the surfaces which produce radiation, on the rear fuselage section 8 results in the "hot" surfaces of the decoy 1 which produce IR radiation -in the same way as the hot engine parts of the aircraft -being visible primarily from the rear, and less from the front, by the threat or the IR target homing head. While, in the case of the decoy according to the prior art, the ratio of the intensity of the radiation emitted backwards to the radiation emitted forwards is about 2:1, the design of the decoy according to this invention results in considerably greater intensity ratios being achieved. This also corresponds to the ratios which occur with aircraft. However, this design also provides a better simulation of the spectral characteristics of the IR aircraft signature as a function of the aspect angle, in the case of which the area where the radiation is weaker and which is also "colder" is located in the front in the direction of flight, and the part where the radiation is more intensive, which is totter", is located at the rear in the direction of flight. This makes it considerably harder for enemy target homing heads which operate with intensity threshold switches and/or spectral identification in the middle or near IR band to identify the deployed decoy or the deployed apparent target as a false target.

In addition, the structure of the front section 7 of the decoy may have fitted to it material whose spectral radiation maximum occurs at considerably longer wavelengths than in the case of the material in the rear section 8. This allows the spectral simulation of the IR signature to be improved even further for specific aircraft.

As the aircraft speed increases, and thus as the air incident-flow velocity around the decoy 1 increases, the IR power emitted by a decoy decreases. This is an undesirable effect. According to the prior art, the degradation of the lR power which is caused by the increase in the incident-flow velocity with the aircraft speed, is compensated for by the material which produces the IR radiation having a higher radiation temperature in which case, in the prior art, this material was distributed over the entire structure of the decoy. However, in consequence, the spectral mismatch -9-.

between the decoy and the aircraft increases, which relatively modern target homing heads can once again utilize for flare discrimination.

In contrast, the configuration of the IR decoy 1 according to this invention with the braking flaps 10 and/or with the junction (which reduces the surrounding flow speed) at the point 9 from the front fuselage section 7 with the larger cross section to the rear fuselage section 8 with the smaller cross section results in the surrounding flow speed being reduced locally behind the braking flaps 10. This reduction in the surrounding flow speed of the air can also be promoted by a corresponding shape of the towing eye 5.

Reducing the local surrounding flow speed of the air on the rear section 8 of the decoy 1 reduces the described degradation of the lR power that is emitted. This allows the decoy 1 to emit a spectral distribution of the IR power which is more similar to that of the aircraft to be protected.

The ratios of the lengths of the front fuselage section 7 and of the rear fuselage section 8 can be matched to the application and to the amount of power which is intended to be emitted from the rear fuselage section 8. It may be advantageous to provide the IR decoy 1 with as short an overall length as possible, in order to keep the launcher (dispenser) volume provided for the decoy 1 as small as possible.

As an alternative to the described embodiment of the lR decoy 1 according to this invention, the front fuselage section 7 and the rear fuselage section 8 may have the same diameter, or diameters which are not significantly different. However, in this case, the braking flaps 10 are -10 -arranged in such a way that the incident-flow velocity of the air on the rear fuselage section 8 is considerably less than that on the front fuselage section 7. In addition, if the front section 7 has a larger diameter than the rear section 8, a step or some other precaution equivalent to this can be provided at the point 9, by means of which the airflow and the resultant vortex formation result in a reduction in the relative speed by which the air flows around the decoy 1. Such desirable additional vortex formation can also be achieved by appropriately arranged metal plates.

Designing the IR decoy 1 with a cylindrical shape has the advantage that it can also be fitted into standard dispensers for decoys or flares, which are in any case also intended for cylindrical geometries. In this case, it has been found to be advantageous with respect to a maximum deceiving effect at aspect angles around 900, to choose installation locations for the dispenser or launcher in the aircraft to be protected, which are very close to those points on the aircraft which produce the most intensive radiation. However, the decoy 1 may also have any other cross-sectional shape, such as an elliptical shape, in order to achieve better stabilization of the towed decoy 1 in the flow field of the aircraft.

In order to improve the effectiveness of the IR decoy 1 according to the invention, a method for its deployment is provided which adapts or controls the separation rate of the IR decoy as a function of the angle between the threatening missile velocity vector and the aircraft velocity vector. The rate at which the towing cable 3 is paid out is adapted in a -11 -corresponding manner, as a function of the aspect angle of the threatening missile.

The control system shown in Figure 2 is provided for controlling these processes. This control system has a missile warner 23 and a control unit 24 within the corresponding aircraft system 21. When an appropriate threat occurs, the missile warner 23 passes control signals via a cable 23a to the control unit 24. The control unit 24 is connected via a cable 24a to a winding apparatus 25, which uses appropriate signals from the control unit 24 to unwind the towing cable 3, or under some circumstances even to wind it up again, and thus to set or vary the rate of separation of the JR decoy I from the aircraft.

The geometric relationships required to describe the angular separation between the aircraft and the decoy which can be perceived by the target homing head of the threatening missile are shown in horizontal section in Figure 3, and in vertical section in Figure 4. Figure 3 shows the aircraft 31 to be protected, and the decoy 32 which is deployed from it and is held by means of the towing cable 3. The distance 31a between the decoy 32 and the aircraft 31 is thus a function of the respective extended section of the towing cable 3; this distance is denoted by L in the following text. The reference number 33 represents an IR missile having an appropriate target homing head, which is threatening the aircraft 31. The distance between the JR missile 33 and the aircraft 31 is denoted by 33a, and its magnitude is R. The distance between the lR missile 33 and the -12 -decoy 32 is denoted by the reference number 33b. In the illustration in Figure 3, the aircraft velocity vector is denoted by the reference number 34.

The angle between the aircraft velocity vector 34 and the sightline 33a between the IR missile 33 and the aircraft 31 is called the aspect angle. In S the horizontal section, the aspect angle is equal to the azimuth angle 35a.

Figure 4 shows a vertical section of the same arrangement, so that the same items and references are provided with the same reference numbers. In the vertical section, the aspect angle is equal to the elevation angle 35b.

The length of the extended section of the towing cable 3 results in a distance 36, seen from the JR missile 33, which is denoted Left in the following text, as well as a perceptible separation angle Aip. On the basis of known trigonometric relationships, the separation angle Ap which can be perceived from the IR missile 33 is given arithmetically by: Aip = LeSR = vp At sin (aspect angle)/R.

In this formula, indicates the rate of separation, that is to say the relative speed between the decoy 32 and the aircraft 31, which is governed by the rate at which the winding apparatus 25 unwinds. At in this case means the time during which the decoy 32 has been extended at a constant rate Vsep. The aspect angle is formed, in accordance with known relationships, from the respective azimuth angle and elevation angle.

-13 -The situation where the rate of separation Vsep varies with time is covered by the relationship: = dt sin (aspect angle).

The effectiveness of the decoy requires that a sufficient angular -separation be produced between the decoy and the aircraft 31 to be protected. However, this must not be excessively large in the initial phase of the deployment process, to ensure that the IR decoy is still within the to field of view of the detecting target homing head at the time when it blooms.

The angular separation which can be perceived by the detecting target homing head between the deployed decoy 32 and the aircraft 31 varies considerably with the aspect angle, that is to say the threat direction relative to the aircraft velocity vector 34 (see Figures 3 and 4). If, for example, the rate of unwinding is set such that the angular separation is sufficient to deflect the detecting target homing head of the IR missile 33 when the threat is from the side at an aspect angle of about 9Q0, then the rate of unwinding that has been set is insufficient for significantly greater or smaller aspect angles 35. In this case, there is then a risk of the IR target homing head not being adequately deflected away from the aircraft, so that the explosive warhead of the lR missile 33 can detonate too close to the aircraft 31.

-14 -The invention provides for the deployment of the decoy 32, and thus for the rate at which the line is paid out and the rate of separation v, to be controlled as a function of the aspect angle. To this end, a missile warner 23 with high angular resolution, typically of not less than 5°, is installed in the aircraft 31 (see Figure 2). The warning signals are passed via the cable 23a to the control unit 24. The control unit 24 uses the measured aspect angle, which is preferably determined from the azimuth angle and elevation angle, to adapt the rate at which the towing cable 3 is paid out, and passes appropriate control signals to the dispenser or launcher. If, for example, the rate of separation of the decoy on the towing cable 3 is optimized for a threat at an azimuth angle 35a of 90°, then a higher rate, corresponding to the described trigonometric functions, must be set for other azimuth angles.

Small aspect angles, or azimuth or elevation angles, are subject to a minimum value for use in the calculation. In this case, rapid deployment of the decoy, that is to say a high rate of separation, is not sufficient on its own. In fact, the deployment of the towed decoy must be linked to suitable aircraft manoeuvres, in order to achieve adequate angular separation between the aircraft 31 and the decoy 32.

The described method means that, during flight, the rate of separation of the decoy 32 to be deployed can be automatically adapted in accordance with the aspect angle. This improves the deceiving effectiveness, since the angular separation which can be perceived by the -15 -IR target homing head is largely dependent on the aspect angle, that is to say it can be produced independently of the direction of flight of the threatening missile with respect to the direction of flight of the threatened aircraft.

Claims

-16 -Claims 1. IR decoy for use on an aircraft for deceiving missiles having lR target homing heads, wherein the IR decoy emits IR radiation in the spectral band which is relevant for the IR target homing heads, the decoy being deployed from a launcher carried by the aircraft and towed by a cable, the IR decoy having braking means and the zone which emits the IR radiation being located behind the said braking means as seen from the aircraft.
2. IR decoy according to Claim 1, wherein the braking means comprise movable flaps forming air-brakes.
3. IR decoy according to Claim 1 or 2, wherein the braking means are arranged to be deployed by extension.
4. IR decoy according to any one of the preceding claims, wherein the IR decoy has, at a junction between a forward fuselage section and a rear fuselage section, a step which reduces the speed of the air flowing around the rear fuselage section.
5. IR decoy according to any one of the preceding claims, wherein the IR decoy has a front fuselage section and a rear fuselage section, the -17 -front fuselage section having a larger diameter than the rear fuselage section.
6. IR decoy according to any one of the preceding claims, wherein the front fuselage section incorporates a material which produces radiation and whose spectral radiation maximum occurs at considerably longer wavelengths than the spectral maximum of the radiation from the rear fuselage section.
7. IR decoy according to any one of the preceding claims, wherein a connection for securing the towing cable is provided in the zone of the front fuselage section which causes the radiation produced on the rear section of the decoy to be shadowed in the direction of the aircraft.
8. IR decoy for use on an aircraft for deceiving missiles having IR target homing heads, wherein the IR decoy emits IR radiation in the spectral band which is relevant for the IR target homing heads, the decoy being deployed from a launcher carried by the aircraft and towed by a cable, wherein the rate of paying-out the towing cable is varied controllably as a function of the aspect angle of the incoming missile.
9. Control unit for controlling the rate of paying-out of the towing cable by means of which an IR decoy is connected to an aircraft in order to -18 -deploy the decoy, wherein the paying-out rate has a minimum value at aspect angles of 90°, and increases at lesser or greater aspect angles.
10. Control unit according to Claim 9, wherein the paying-out rate is varied with the aspect angle on the basis of the reciprocal of the sine of the aspect angle.
11. Control unit according to Claim 9 or 10, wherein the values for the aspect angle are derived from angle data transmitted by a missile io alerting means, which angle data indicate the current relative position of the missile with respect to the aircraft, determined by means of an appropriate sensor system.
12. Control unit according to Claim 9, 10 or 11, wherein the values for the aspect angle are formed from the respective azimuth and elevation angles.
13. Method for deploying an IR decoy to protect an aircraft against a missile having an IR target homing head, in which the decoy is deployed on a towing cable from the aircraft at a deployment rate which is a function of the aspect angle which is covered by the lines of sight originating at the missile to the aircraft and to the PR decoy.

-19 -
14. Method fordeploying an IR decoy according to Claim 13, in which the rate of deployment is proportional to the reciprocal of the sine of the aspect angle which is covered by the lines of sight, originating from the missile, to the aircraft and to the IR decoy.
15. An IR decoy for use on an aircraft for deceiving incoming lR homing head equipped incoming missiles constructed and arranged to function as described herein and exemplified with reference to the drawings.
16. Method for deploying an IR decoy to protect an aircraft against a missile having an IR target homing head as described herein and exemplified with reference to the drawings.
17. A control unit for controlling the rate of paying-out of the towing cable by means of which an IR decoy is connected to an aircraft in order to deploy the decoy, as described herein and exemplified with reference to the drawings.
18. An aircraft incorporating an IR decoy means according to any preceding Claim 1 to 7.Amendments to the claims have been filed as follows Claims - 1. An IR decoy system for use on an aircraft for deceiving missiles having IR target homing heads, wherein an IR decoy emits IR radiation in the spectral band which is relevant for the IR target homing heads, the decoy being deployed from a launcher carried by the aircraft and towed by a cable, the IR decoy having braking means and the zone which emits the IR radiation being located behind the said braking means as seen from the aircraft.2. An IR decoy system according to Claim 1, wherein the braking means comprise movable flaps forming air-brakes.3. An IR decoy system according to Claim 1 or 2, wherein the braking means are arranged to be deployed by extension.4. An lR decoy system according to any one of the preceding claims, wherein the IR decoy has, at a junction between a forward fuselage section and a rear fuselage section, a step which reduces the speed of the air flowing around the rear fuselage section.5. An IR decoy system according to any one of the preceding claims, wherein the IR decoy has a front fuselage section and a rear fuselage section, the front fuselage section having a larger dian-ieter than the rear fuselage section.6. An IR decoy system according to any one of the preceding claims, wherein the front fuselage section incorporates a material which produces radiation and whose spectral radiation maximum occurs at considerably longer wavelengths than the spectral maximum of the radiation from the rear fuselage section.7. An lR decoy system according to any one of the preceding claims, wherein a connection for securing the towing cable is provided in the zone of the front fuselage section which causes the radiation produced on the rear section of the decoy to be shadowed in the direction of the aircraft 8. An IR decoy and a launcher apparatus for use on an aircraft for deceiving missiles having IR target homing heads, wherein the IR decoy emits lR radiation in the spectral band which is relevant for the lR target homing heads, the decoy, in use, being deployed from the launcher carried by the aircraft and towed by a cable connected between the decoy and launcher, the IR decoy having braking means and the zone which emits the IR radiation being located behind the said braking means as seen from the aircraft, the rate of paying-out the towing cable being varied controllably as a function of the aspect angle of the incoming missile.9. An IR decoy and a launcher apparatus according to claim 8, including a control unit for controlling the rate of paying-out of the towing cable by means of which an lR decoy is connected to an aircraft in order to deploy the decoy, wherein the paying-out rate has a minimum value at aspect angles between a missile and aircraft of 90°, and increases at lesser or greater aspect angles.10. An JR decoy and a launcher apparatus according to ClaimS or 9, wherein the paying-out rate is varied with the aspect angle on the basis of the reciprocal of the sine of the aspect angle.11. An IR decoy and a launcher apparatus according to any one of Claims 8 to 10, wherein the values for the aspect angle are derived from angle data transmitted by a missile alerting means, Which angle data indicate the current relative position of the missile with respect to the aircraft, determined by means of an appropriate sensor system.12. An lR decoy and a launcher apparatus according to any one of Claims 8 to 11, wherein the values for the aspect angle are formed from the respective azimuth and elevation angles.13. A method for deceiving missiles having lR target homing heads and using an lR decoy which emits JR radiation in the spectral band which is relevant for the JR target homing heads, in which method the decoy is deployed from a launcher carried on an aircraft and towed by a cable, a braking means being deployed from lR decoy and the zone which emits the lR radiation being located behind the said brakingmeans as seen from the aircraft.14. A method for deceiving missiles in accordance with claim 13, in which the deployment rate of the decoy is a function of the aspect angle which is covered by the lines of sight originating at the missile to the aircraft and to the IR decoy.15. A method for deceiving missles in accordance with Claim 13 or 14, in which the rate of deployment is proportional to the reciprocal of the sine of the aspect angle which is covered by the lines of sight, originating from the missile, to the aircraft and to the IR decoy.-16. An IR decoy system for use on an aircraft for deceiving incoming IR homing head equipped incoming.missiles constructed and arranged to function 20-as described herein and exemplified with reference to the drawings.17. A method for deceiving missiles by deploying an IR decoy to protect an aircraft against a missile having an IR target homing head as described herein and exemplified with reference to the drawings.18. An aircraft incorporating an IR decoy system according to any preceding Claim ito 12.