DK2761245T3 - Active protection system - Google Patents

Description

Active protection system Description

The invention concerns a protection system that is formed of at least one active decoy based in particular on van-Atta arrays, for protecting objects such as ships, vehicles, stationary objects etc. against incoming radar-guided (active) missiles. This is an off-board protection system that has been proven less as an interference means but rather as a decoy in the close range from 10m up to a distance of I Okm. In this case, a radar lobe of the incoming missile is used directly for generation and radiated back thereto without altering the properties. A directional antenna adjustment or adjustment of the characteristics is not necessary.

For combatting active missiles, passive decoys (chaff) are known. These are deployed and reflect a signal radiated by the missile back in the direction of the incoming missile. A passive radar decoy is described by US 3,938,151 Ad, A passive electromagnetic reflector is known from US 2,908,002 AI.

An active countermeasure using passive decoys against passive missiles is proposed by DE 10 2006 01? 107 Al. in this case, the decoys are preferably illuminated by their own radar and said radar radiation is reflected towards the missile. Said radiation has exactly the same characteristics as the direct radiation of the radar. Indeed, the missile cannot distinguish in this case whether it is a decoy or the correct radar; efforts are ongoing to enable more modern missiles to distinguish decoys from real targets.

Alternative active decoys, such as for example those mentioned in DE 600 10 701 T2, are as a rule only activated on deployment, so that a certain time is to be allowed until the decoy has completely unfolded. DE 100 16 781 Al discloses the preamble of Claim I. it is the object of the invention here to reveal an active decoy for protecting objects, in particular ships, against incoming radar-guided missiles.

The object is achieved by the features of Claims 1, 9 and it. Advantageous embodiments are addressed in the subordinate claims.

The invention is based on the idea of providing an active decoy by the use of a retro-reflector or a retro-directive antenna, preferably in the form of a van-Atta array or by at least one backscatter system, with means therefore to be able to actively and accurately send the radar signal back in the incident direction and thereby to the missile.

The design of a broadband frequency offset of a van-Atta array can be obtained from the Internet page A. planar van-Atta array is disclosed oft http://ir. lib, nctu,edu.fw/bitstream/987654321/22239/1 /01033 7018.pdf. GB 1 284 747 specifies an antenna device using a vart-Alia array. The use of a retro-directive antenna in the form of a van-Atta array for providing RFID systems is known from BE 10 2005 037 583 A!.

The use of a retro-reflector as an active decoy is ad vantageous becaitse as an active retro-reflector the same produces a large radar backscatter frequency cross section (RCS), which enables the generation of a large RCS for any polarisations of the missile.

In this case, however, it is to be taken into account that a single van-Atta array - a single retro-directive antenna ~ is not capable of determining the direction of an incident signal Therefore, in the simplest version a sensor for determining the direction of the incoming missile can be incorporated into the device in addition to said array. Said information is then used to orient the array in said direction.

In continuation, it is however preferably provided that a plurality of arrays are connected together, whereby the same do not just cover a broad spatial area, but are also enabled - for example with the aid of servomotors etc. - to automatically align with the incoming missile. At the same time, the incident direction of the incoming missile is determined by the array and said information is passed to a position controller, which acts on servomotors etc. of the decoy, i.e. of the array. in order ίο align the decoy optimally with the missile A dual-polarised implementation enables the use of the reflector with any polarisation of the missile (orientation of transverse waves in a preferred direction) by using suitable antennas and the wiring thereof. For the estimation of direction, the signals running in the van-Atta array are tapped at amplifiers and fed into an electromagnetic lens, for example a Rotman lens. In this way, the receiving antenna array acts both as part of the van-Atta array and for the Rotman lens. At the out put port, of the Rotman lens, the signal power is detected or tapped, so that by comparing the power the incident direction of the signals and hence the direction of the incoming missile can be determined. Said information is then used to be able to carry out position control tor tracking the array.

Using a simply represented exemplary embodiment, the idea will be described in detail, in the figures;

Fig. 1 shows a sketched representation of an active decoy tor combatting missiles.

Fig. 2 shows a first simplified represented version of the active decoy from Fig. 1, Fig. 3 shows a further version of the decoy from Fig. 1 in the form of a simple circuit diagram.

In Fig. I, a protection system 20 is shown that comprises an active decoy 1 for combating the threat to an object 4 against a radar-guided missile 5 in a sketched representation for general understanding. The active decoy 1 comprises at least, one retro-directive antenna or retro-reflector 2. which can be formed at least of a receiving and transmitting antenna as a reflector or a reflecting antenna, but also of a plurality of objects, in order to send back the radar beam Rp emitted by the missile 5 accurately in the incident direction and thereby to the missile 5 as a reflection beam Rs. The active protection system 1 is carried on or around the object 4, in this case a ship, as an off-board version when not in use.

In a very simple version (Fig. 2), in addition a sensor 6 is also involved in the protection system 20 that is used for detection of the direction of the missile 5 and thai works in conjunction with an actuator (not shown in detail), by which at least the decoy i can be brought into the corresponding position or direction. in this case, two different functional modes of the decoy 1 are possible. One mode is distraction - when the missile 5 has not yet locked onto the object 4, the other mode is seduction, the separation of the decoy from the real target, a version when the missile 5 has already acquired the actual target (object 4). in the case of initiating distraction, the missile 5 is detected as a passive missile, which for its part is monitoring an expected area. The direction, distance and speed of the missile 5 are determined Then, using the incoming information the decoy 1 is deployed at an early stage to provide an attractive target 4’ at a distance trom the actual target 4 with the decoy 1. in this case, it is also taken into account which search process is preferable for the detected missile 5. If the missile 5 is radiating the radar lobe thereof this is already carried out towards the decoy 1, preferably before the missile has yet detected the actual object 4. in the event of seduction, likewise a passive method, a radiated target signal is detected by further detectors, for example an active radar and radar warners, which are preferably attached to the object 4. Said radiated target signal of the missile 5 is received by the decoy 1 and radiated back to the missile 5 in amplified form. The decoy Ϊ itself is moving away from the object 4 during this at a speed similar to that of the object 4.

The decoy 1 can fly away from the object 4, preferably at the maximum object altitude, This applies to ships as well as to other moving objects 4, for example vehicles. In the case of ships that are to be protected, the decoy 1 can be moved away by floating or being passively towed. Automatic driving away or towing away is also possible with vehicles on land.

The preferred embodiment of the decoy 1 itself is represented by Fig. 3 In this case, the decoy 10 consists of an antenna i 1 that consists of a plurality of receiving antennas 11,1-11.3 (1 i.n) and an antenna 12 that consists of a plurality, preferably the same number, of transmitting antennas 12.1-12.3, I2.n. According to the number of antennas 11, 12, amplifier stages are incorporated V* - Va,.l|a between the two types of antennas

With the antennas H.l-ll. 3, in addition to receiving the radar beam Rf, the incident direction of the incoming missile 5 can also be determined. For the estimation of direction, the signals running in the antenna group 11 are tapped at amplifiers Vi- Vs and fed into an electromagnetic lens 13, for example a Rotman lens. The output information thereof is compared in a comparator 14. For this the outputs thereof are fed to the comparator or to an analysis unit 14. Using the tapped signals, the direction of incidence of the signals and thereby the direction of the incoming missile 5 are now determined in the analysis unit 14. During this, the signal differences of the antennas 11.1-11.3 are analysed. During the analysis, a command is given to a position controller 15, which for its part acts on the servomotors 16 etc., i.e., the actuator of the decoy 10 or the protection system 20, in order to optimally align at least the decoy 10 with the missile 5. For control purposes, however, a direction sensor 6 can also be incorporated into the analysis here

The antennas 11 and 12 are preferably embodied in the form of a van-Atta array

Claims (13)

1. Beskyttelsessystem (20) til beskyttelse af et objekt (4) mod et radarstyret missil (5), med et aktivt skinmål (1, 10), der dannes af i det mindste en retroreflektor eller en retrodi-rektiv antenne (2, 11, 13), der kan sende en radarstråle (Rf) som refleksionsstråle (Rs) nøjagtigt i indfaldsretningen og dermed tilbage til missilet (5), kendetegnet ved, at • skinmålet (10) består af en antenne (11) med flere modtageantenner (11.1-11.3, lln) og en sendeantenne (12) med flere sendeantenner (12.1-12.3, 12.n), hvor der svarende til antallet af antenner (11, 12) er integreret forstærkertrin (V1-V3, Vn) mellem begge, • for en retning s vurdering udtages de i modtageantennerne (11.1-11.3, lln) løbende signaler ved forstærkerne (V1-V3, Vn) og fødes til en elektromagnetisk linse (13), hvis udgange ledes til en komperator (14), hvor • komperatoren (14) er koblet med en positionsreguleringsenhed (15), der på sin side indvirker på reguleringsmotorer (16) i skinmålet (1, 10) og/eller beskyttelsessystemet (20) for i det mindste at orientere skinmålet (1, 10) optimalt mod missilet (5).Protection system (20) for protecting an object (4) from a radar-guided missile (5), with an active skin target (1, 10) formed by at least one retroreflector or retro-directive antenna (2, 11) , 13) capable of accurately transmitting a radar beam (Rf) as a reflection beam (Rs) in the direction of approach and thus back to the missile (5), characterized in that • the target (10) consists of an antenna (11) with multiple receiving antennas (11.1) -11.3, lnn) and a transmitting antenna (12) with multiple transmitting antennas (12.1-12.3, 12.n), with the corresponding number of antennas (11, 12) having integrated amplifier stage (V1-V3, Vn) between both, for a direction's evaluation, the signals in the receiving antennas (11.1-11.3, ln) are taken at the amplifiers (V1-V3, Vn) and fed to an electromagnetic lens (13), the outputs of which are directed to a comparator (14), where the • comparator (14) is coupled to a position control unit (15), which in turn acts on control motors (16) in the target (1, 10) and / or the protection system (20) to at least orient the target of target (1, 10) optimally towards the missile (5). 2. Beskyttelsessystem (20) ifølge krav 1, kendetegnet ved, at den elektromagnetiske linse (13) er en Rotman-linse.Protection system (20) according to claim 1, characterized in that the electromagnetic lens (13) is a Rotman lens. 3. Beskyttelsessystem (20) ifølge krav 1 eller 2, kendetegnet ved, at den retrodirektive antenne (2) består af mindst en modtage- og reflektorantenne.Protection system (20) according to claim 1 or 2, characterized in that the retro-directional antenna (2) consists of at least one receiving and reflecting antenna. 4. Beskyttelsessystem (20) ifølge et af kravene 1 til 3, kendetegnet ved, at der realiseres en dual polarisering med antennerne (11, 12).Protection system (20) according to one of claims 1 to 3, characterized in that a dual polarization is achieved with the antennas (11, 12). 5. Beskyttelsessystem (20) ifølge et af kravene 1 till 4, kendetegnet ved, at skinmålet (1) kobler sig på missilet (5) ved distraktion eller seduktion.Protection system (20) according to one of claims 1 to 4, characterized in that the target target (1) engages the missile (5) by distraction or seduction. 6. Beskyttelsessystem (20) ifølge krav 5, kendetegnet ved, at der til seduktion er anbragt yderligere detektorer, eksempelvis en aktiv radar og radaradvarselsindretning, fortrinsvis på objektet (4).Protection system (20) according to claim 5, characterized in that additional detectors are arranged for seduction, for example an active radar and radar warning device, preferably on the object (4). 7. Beskyttelsessystem (20) ifølge et af kravene 1 til 6, kendetegnet ved, at skinmålet (1, 10) kan fjerne sig fra objektet (4) flyvende, fortrinsvis i maksimal objekthøjde.Protective system (20) according to one of claims 1 to 6, characterized in that the target (1, 10) is capable of moving away from the object (4) flying, preferably at maximum object height. 8. Beskyttelsessystem (20) ifølge et af kravene 1 til 7, kendetegnet ved, at skinmålet (1, 10) kan bevæges videre flydende eller trukket passivt.Protection system (20) according to one of Claims 1 to 7, characterized in that the target (1, 10) can be moved further liquid or passively drawn. 9. Fremgangsmåde til beskyttelse af et objekt (4) mod et radarstyret missil (5) under anvendelse af et beskyttelses system (20) ifølge et af kravene 1 til 8, kendetegnet ved følgende trin: • at identificere et missil (5) som passivt missil, der på sin side overvåger et forventning so mråde • at beregne missilets (5) retning, afstand og hastighed, • at indsætte skinmålet (1, 10) til dannelse af et attraktivt mål (4’) i en afstand fra det egentlige objekt (4), således at • når missilet (5) udstråler sin radarsløjfe, sker dette allerede i retning af skinmålet (1,10), fortrinsvis endnu inden dette har registreret det egentlige objekt (4).Method for protecting an object (4) from a radar-guided missile (5) using a protection system (20) according to one of claims 1 to 8, characterized by the following steps: • identifying a missile (5) as passive missile, which in turn monitors an expectation so that: • to calculate the direction, distance and velocity of the missile (5), • to insert the target target (1, 10) to form an attractive target (4 ') at a distance from the actual object (4) so that • when the missile (5) radiates its radar loop, this already occurs in the direction of the target of target (1,10), preferably even before it has detected the actual object (4). 10. Fremgangsmåde ifølge krav 9, kendetegnet ved, at der også tages højde for, hvilket søgningsforløb det detekterede missil (5) foretrækker.Method according to claim 9, characterized in that the search course of the detected missile (5) is also taken into account. 11. Fremgangsmåde til beskyttelse af et objekt (4) mod et radarstyret missil (5) under anvendelse af et beskyttelsessystem (20) ifølge et af kravene 1 til 8, kendetegnet ved følgende trin: • at detektere et udstrålet målsignal fra missilet (5), • at optage det udstrålede målsignal med skinmålet (1, 10), • at tilbagesende det forstærkede udstrålede målsignal til missilet (5), hvor • skinmålet (1, 10) under dette bevæger sig bort fra objektet (4) i objekt lig nende hastighed.Method for protecting an object (4) from a radar-guided missile (5) using a protection system (20) according to one of claims 1 to 8, characterized by the following steps: • detecting a radiated target signal from the missile (5) , • recording the radiated target signal with the target target (1, 10), • returning the amplified radiated target signal to the missile (5), where • the target target (1, 10) moves away from the object (4) in object-like velocity. 12. Objekt (4) med et beskyttelses system (20) ifølge et af kravene 1 til 8.An object (4) with a protection system (20) according to one of claims 1 to 8. 13. Objekt (4) ifølge krav 12, kendetegnet ved, at der ved objektet er tale såvel om skibe som om andre objekter (4), der bevæger sig, f.eks. køretøjer.Object (4) according to claim 12, characterized in that the object is both vessels and other objects (4) moving, e.g. vehicles.