CH685517A5 - Multispectral decoy. - Google Patents

Description

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The use of search heads with one or more sensors that work in spectral ranges from the ultraviolet to the visible, the infrared to the millimeter range is becoming increasingly important. In particular, several spectral ranges are increasingly being evaluated at the same time in order to minimize the susceptibility to faults and incorrect sensing. Combinations of IR sensors with sensors that are sensitive in the radar range, in particular millimeter wave range, are used, for example. The resolving power of the sensors used is also constantly being improved, so that targets can not only be recognized but also precisely identified. In order to protect military objects and weapon systems from attack bodies equipped with such sensors, smoke and fake targets are used. Fog agents are suitable for ammunition attacking flat, while sham targets are primarily used to protect against ammunition that attacks vertically or very steeply.

For example, armor-piercing submunition, which attacks steeply or vertically, is used to attack both stationary and moving targets, which is ejected from airborne dispensers, from artillery and mortar shells and from missiles. The submunition is released at a predetermined height above the target, usually about 300 m, depending on the type of warhead, triggered by a time fuse. At one end of the ammunition, a parachute opens, which brakes it, and at the same time, mechanical devices such as e.g. fold-out wing, the twist is reduced. After the brake parachute is pushed off, the main parachute opens, which is constructed in such a way that the ammunition is guided across the battlefield with the speed required for the aiming process and the correct slope or aspect angle in ever narrowing spirals. The sensors of the seeker head search in the respective spectral ranges, e.g. in the IR range and millimeter wave range, according to target-typical features, e.g. in the IR range for a target that is warmer than the surroundings, in the radar range for radar reflection and thus at the same time for jumps in altitude. If these target criteria are met, the projectile-forming charge acting in the sensor direction is triggered, which is then intended to hit and destroy the target. If the search head finds a target that fulfills the criterion in the IR range - warmer than the surroundings - but not the criterion in the other evaluated range, this target is recognized as a false target. Such submunition is described, for example, in Military Technology Miltech 2/90, pages 27 to 34. An essential property of this submunition is that it has multispectral sensors.

For this purpose, it is now known to deflect sensors acting in the IR range by simulating a heat target. For example, DE-OS 3 205 599 proposes using an electrically resistance-heated material as a target for deception, lure and practice. Furthermore, it is known from DE-OS 2 930 936

To deceive radar and infrared search devices by combining an exothermic substance with a three-dimensionally shaped radar reflector, the exothermic substance acting as a pyrophoric incendiary in a spatially and temporally coordinated manner.

From International Defense Review 9/1990, page 1034, it is known to use an inflatable body as a dummy target, which essentially has the external appearance of the target to be protected. This body can be equipped with radar reflectors and heating sources. However, this dummy target has the disadvantage that it is complex to manufacture and difficult to handle due to the very precise replica of the dummy target.

Furthermore, it is known from DE-OS 3 312 169 to use inflatable air mattress-like hollow bodies made of metallized plastic film consisting of several chambers as a false target. However, such a hollow body is not suitable for deflecting a submunition with a multispectral sensor, since it is easily recognized by the multispectral sensor as an apparent target. The device provided in this reference for generating a resonance frequency in order to build up a radar signature also has the disadvantage that the attacking sensor must be known and the properties must be established during the manufacture of the hollow body. A flexible setting is not possible.

Military technology 11/74, pages 488 to 491, furthermore describes that a thermal camouflage of ships is possible by cooling the heated surfaces with sea water.

With the previously known false targets, however, it is not possible to divert modern multispectral ammunition from the real target by means which act over a long time and can be built up in a short time.

It was therefore an object of the invention to provide a multispectral mock target that can be used in a variety of ways, protects both stationary and movable military objects from steeply attacking ammunition provided with a multispectral seeker head, can be set up in a short time, works for a long time without additional personnel requirements and has a high effectiveness, while at the same time the function of the weapon system to be protected must not be hindered.

This object is achieved by a multispectral apparent target, comprising a body which can be heated at least to the temperature of an object to be protected as a real target and which can be controlled from the object to be protected, and at least two corner reflectors which are attached to rods adjacent to the heatable body at different distances from the ground or attached to rods that can be extended from the object to be protected or that are stretched over a metal rod.

The combination according to the invention provides very good protection for targets threatened by vertically attacking search fuse ammunition, which can be stationary, semi-stationary or mobile, and reduces

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the hit probability for such objects to less than 15%.

Protected by the dummy target according to the invention are, for example, guns, anti-aircraft weapon systems in firing positions, tanks, self-propelled howitzers, missile artillery positions or gun positions.

The apparent target according to the invention comprises a heatable body, which is preferably an electrically heatable mat and is heated from the object to be protected via a line. The heatable body can have the area of the object to be protected. For transport reasons, it is preferably dimensioned smaller. Temperature sensors on the object to be protected and on the heatable body are preferably used to regulate the temperature of the body in such a way that the heat radiation cannot be distinguished from the real and the apparent target. Has e.g. the dummy target is the same size as the real target, the temperature of the dummy target is only adjusted to that of the real target. Is the apparent target, e.g. for transport reasons, smaller than the real target, the temperature of the dummy target must be increased accordingly in order to achieve the necessary target-typical heat radiation.

In a preferred embodiment of the dummy target according to the invention, the heatable body is not heated uniformly, but areas with different temperatures are provided. In particular, a temperature distribution is simulated, as is typical for the object to be protected. For example, in the case of a tank as the object to be protected, the heatable body of the dummy target can be designed such that it has an area which has the temperature of the hot-shot tube of the tank, an area which is the temperature of the engine and one which is the temperature of the Exhaust area of the tank.

If the false target is attached to a mobile object, the heatable body is preferably a foldable mat that can be unfolded in use. The surface of the heatable body can also be made electrically conductive by appropriate coating, so that it reproduces the metallic surface of the object to be protected and provides protection against passive radiometers in the millimeter wave range.

The second component of the combination according to the invention is formed by at least two corner reflectors. The corner reflectors reflect radiation in the millimeter wave range, preferably in the range of more than 30 GHz, and particularly preferably at 90 to 100 GHz. Preferred as corner reflectors with metal, e.g. Nickel or silver, coated fabrics are used which can be folded up so that they take up a small volume during storage and can be quickly unfolded when building the dummy target, e.g. using a metal rod similar to an umbrella. Metal-coated fabrics reflecting in the desired wave range are known per se and can be used here.

The corner reflectors are

arranged at different distances from the floor adjacent to the heatable body. The distances are such that they correspond to the jumps in height of the object to be protected. For example, if a tank or a howitzer is to be protected, the corner reflectors can be arranged at the level of the tank pan and at the level of the tank tower. The corner reflectors can be set up by attaching them to rods rammed into the ground or rods that can be extended from the object to be protected, or by means of a metal rod.

The apparent target according to the invention can be set up quickly and without great expenditure of personnel and time. If the apparent target serves to protect stationary objects, the heatable body is preferably placed on the floor and the Corner reflectors are attached above it, e.g. spanned. If a mobile target is to be protected, rods, preferably telescopic tubes, which can be extended to the desired distance from the object to be protected, are attached to the target and have corner reflectors, a heatable body and a power supply cable. The poles can, for example, be attached to the roof of the tower or at other suitable locations on the object to be protected. If necessary, these rods can then be extended individually or together, in whole or in part, on the telescopic rods. If they are no longer needed, they can be retracted individually or together.

The duration of action of this false target is not limited and can be independent of external conditions, such as. B. wind and weather, can be chosen according to practical need.

The distance of the dummy target from the object to be protected, the arrangement and number of combined bodies must be selected so that when searching for the target the sensor is always attracted to the dummy target before it can hit the object to be protected. It has now been found that particularly favorable results are obtained if three combinations of heatable body and Cor-ner reflectors are arranged at different heights in such a way that they occupy the corners of an isosceles triangle which fully circumscribes the respective goal, each of which Combination of heatable body and corner reflectors at different heights from the object to be protected has a distance that corresponds to at least half the footprint of the target sensor. The footprint is the distance that the legs of the aspect angle of the seeker head span when they hit the ground, as is shown schematically in FIG. 5. If the dummy target is too far away from the object to be protected, the likelihood that the search head will hit the target instead of the dummy target at the start of the target search is increased. If, on the other hand, the apparent target is too close to the object to be protected, damage to the object to be protected can occur despite deflection of the seeker head.

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men. The corners of the triangle must therefore be at such a distance from the object to be protected that the sensible mass of the target is at no point closer to the apparent target than half the footprint extent. Since the firing direction of the projectile-forming charge is the center of the sensible mass of the target when responding to the apparent target, e.g. with a «footprint» of 6 m, the distance between the dummy target and the real target must be at least 3 m. Theoretically, the apparent target triangle can be oriented around the target. However, in order e.g. When protecting weapon systems so as not to impair their function, the combinations of a heated body and corner reflectors arranged at different heights should preferably not be in the firing direction.

If the individual sham target combinations are arranged directly on the object to be protected via telescopic poles, there is the possibility of extending and retracting the sham goats individually, so that effective protection can be achieved even in unfavorable terrain.

According to the invention, a dummy target is provided that protects stationary as well as mobile weapon systems and military objects from ammunition equipped with search heads.

The invention is further explained below by the drawing. Show in it:

1 shows the structure of a multispectral stationary dummy target,

2 shows the arrangement of a multispectral stationary dummy target with three heatable bodies,

Fig. 3 shows the structure of a multispectral mobile dummy target and

Fig. 4 shows the arrangement of a multispectral dummy target on an extendable telescopic tube.

5 schematically shows the footprint of a search fuse ammunition.

Fig. 1 shows a self-propelled howitzer 1 as an object to be protected with a tower 2 and a tube 3. From the tank, a power cable 4 goes to an electrically heated mat 5. Two corner reflectors 6, 7 are above the heated mat at different distances from Floor arranged, the reflectors 6 and 7 have the height of the tank pan or the turret.

FIG. 2 shows a self-propelled howitzer 21 with a launch tube 23. The self-propelled howitzer 21 forms the center of an isosceles triangle, at the corners of which a heatable mat 25 with two corner reflectors 26/27 is arranged, the corner reflectors as in FIG. 1 are set up. The heated mats 25 each have areas 28 which are each heated in such a way that they have the same heat radiation as the armored pipe 23, while the remaining mat 25 radiates as much heat as the armored tank.

FIG. 3 shows a tank 31 with a launch tube 33, on the turret roof 34 of which three telescopic tubes 39 are attached, which can be extended at the push of a button. On the telescopic tubes 39 are each heatable from the tank unfoldable

Body 35 and corner reflectors 36 attached. The three tubes 39 can be extended to such a length that the heatable bodies with the corner reflectors are located on the corners of an isosceles triangle enclosing the armor.

Fig. 4 shows a telescopic tube 49 containing a power cable, which has a heated mat 45 unfolded. At the end of the telescopic tube 49 there are two corner reflectors 46 and 47 arranged one above the other, which are arranged below the heatable mat, the corner reflector 46 being at the level of the tower and the corner reflector 47 being at the level of the tank pan. The dashed line shows another embodiment in which the corner reflectors 46 and 47 are arranged one above the other above the heatable mat, the corner reflector 46 also being located at the level of the turret and 47 at the level of the armored tank.

5 shows the “footprint” of a search fuse ammunition 52 at the start of the search for a target. The search fuse ammunition 52 rotates at a predetermined angle of inclination, the search head being guided over the battlefield. The legs of the aspect angle 54, 55 stretch a distance, which is referred to as footprint 58, when they hit the ground. If the search head detects a sensible mass, it triggers the charge that acts in the sensor direction. Line 59, which forms the bisector of the aspect angle, indicates the direction of the shot.

Claims (9)

Claims 1. Multispectral apparent target, comprising a body (5; 25; 35; 45) that can be heated and controlled from the object to be protected and at least to the temperature of an object (1; 21; 31) to be protected as a real target and at least two corner reflectors (6 , 7; 26, 27; 36; 46, 47), which are attached adjacent to the heatable body at different distances from the floor on rods or attached to rods (39; 49) which can be extended from the object to be protected or which are stretched over a metal rod. 2. dummy target according to claim 1, characterized in that the heatable body (5; 25; 35; 45) has zones (28) with different temperatures. 3. A false target according to claim 1 or 2, characterized in that the heatable body (5; 25; 35; 45) is a mat which can be heated from the object to be protected (1; 21; 31) and that by temperature sensors on the object to be protected and the heat radiation from the real target and the apparent target can be matched to one another on the heatable body. 4. dummy target according to one of claims 1 to 3, characterized in that the corner reflectors (6, 7; 26, 27; 36; 46, 47) are formed as a fabric coated with metal. 5. dummy target according to claim 4, characterized in that the metal coated fabric is stretched by means of a metal rod. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 4th 7 CH 685 517 A5 6. dummy target according to one of claims 1 to 5, characterized in that the heatable body (25, 35) and the at least two corner reflectors (26, 27; 36) by means of a telescopic rod or a telescopic tube (39, 49) on one as a real target (1, 21, 31) to be protected, are extendably fastened, the heatable body being designed in the form of a foldable mat and the corner reflectors on the telescopic rod or the telescopic tube being arranged at different distances from the floor. 7. dummy target according to one of claims 1 to 6, characterized by three heatable bodies (25, 35) with above or below arranged Cor-ner reflectors (26, 27; 36), which with a predetermined minimum distance and in the form of an isosceles triangle an object to be protected as a real target are arranged. 8. dummy target according to claim 7, characterized in that the minimum distance corresponds to a value of 2.3% of the height that a search detonator ammunition (52) at the start of a target search against the ground. 9. dummy target according to claim 7, characterized in that the minimum distance is 3 meters. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 5