EP1895262B1 - Method and system for defence against ground-to-air missiles - Google Patents

Description

The invention relates to a method according to the preamble of claims 1, 2 and 3.

From the FR 2 718 228 A1 (Starting point for the preamble of each of the independent claims 1-3), a method according to the preamble of claims 1, 2 and 3 is known. From the US Pat. No. 7,051,636 B1 a system for carrying out the method according to the preamble of claims 1, 2 and 3 is known.

During takeoff and landing, military and civilian aircraft may be attacked by Man-Portable Air Defense Systems (Manpads). Such manpads are also available to terrorists around the world and are therefore a serious threat. These ground-to-air missiles are generally older in design and are currently mostly equipped with analogue electronics.

The invention has for its object to provide a method and a system of the type mentioned, with simple means to defend ground-air missiles (= Manpads), which at take-off and landing a threat to military and civil aircraft represent, is suitable.

This object is achieved according to the method by the features of the independent claims 1, 2 or 3.

The Applicant has for several manpads interaction data with respect to their influence by the irradiation with electromagnetic radiation Developed. The examined manpads show different sensitivity profiles over the radiated frequency of the electromagnetic interference radiation. Depending on the frequency of the interference radiation, interference voltages with different amplitudes result on the sensitive signal lines of the analog control electronics of the manpads. In addition, pronounced resonance effects occur. It has also been shown that the resonance frequencies change to a certain extent as a function of the angle of incidence of the radiation (AOI = angle of incidence) of the interfering radiation on the ground-to-air missile.

In addition, such older, an analog control electronics possessing missile have internal operating frequencies. If the interfering radiation which is suitable for ideal launching is additionally modulated or clocked at a frequency which corresponds to the corresponding operating frequency, target loss of the seeker head of the missile to be defended is probable.

A necessary pulse repetition frequency can additionally be superimposed by the frequency of a rolling movement of the missile to be defended.

The behavior of the seeker head and thus the trajectory of the missile to be defended can be simulated. Corresponding simulation tools were developed by the applicant for various manpads. Thus, the effectiveness of an optimized in their parameters electromagnetic interference can be detected.

With pulsed irradiation at the ideal timing frequency, the field strength required for missile defense increases with shorter pulse duration, i. the field strength is inversely dependent on the pulse duration. It is therefore possible in terms of the minimum required field strength and the shortest possible pulse length optimization.

In addition to the dependence of the resonance frequencies on the angle of incidence (AOI), the required field strengths and pulse lengths differ for different missiles as well as the required timing frequencies.

A missile to be defended or a plurality of - also different - attacking missile can according to the invention be subjected after detection with a directional and optionally traceable phase control with an electromagnetic interference radiation. The tracking can be a mechanical or electronic tracking via a phase control (beam steering) act.

The electromagnetic radiation may be Radio Frequency (RF) or Microwave (MW). The waveform radiated by at least one interfering radiation source in terms of frequency, pulse length, pulse amplitude, i. electric field strength, timing, etc., and their time course are such that the at least one attacking missile is permanently disturbed in its functioning, so that it can no longer carry out its mission.

According to the invention a disturbance and thus a defense of a missile by a continuous wave irradiation (CW) with a suitable frequency f is possible. When a manpad is irradiated with a known frequency, which was previously determined in laboratory tests and is ideal for coupling in disturbances, the missile can be deflected from its trajectory. An advantage of continuous wave irradiation is usually that a relatively low field strength amplitude is necessary at the target. Thus, with a given transmission power and antenna configuration, the largest ranges are achievable. However, CW irradiation requires a relatively high power requirement. In addition, with a certain fixed frequency usually only a certain missile to be defended hit. This means that it may be necessary to identify the attacking missile. In addition, at different irradiation i. Incident angles (AOI) usually shifted the ideal coupling frequency, resulting in a reduction of the disturbance or defense effect can result.

To possible deviations from the optimal interference frequency, which may result, for example, by missile-specific and / or trajectory-specific conditions, it is also possible according to the invention to tune the interference radiation frequency over a predetermined frequency range. This requires a slightly greater technological effort and the need to scan the frequency range within a relatively narrow period of time to ensure the appropriate effect on the missile to be defended. Another possibility according to the invention is to use as electromagnetic interference frequency packets of frequency f with a suitable defined pulse repetition rate. That is, as an alternative to the above-mentioned continuous wave irradiation of a missile to be defended this can also be clocked with short pulses of the optimal coupling-in frequency f ₁ irradiated. The required to defend the missile Field strength E ₁ at the target, ie at the missile to be defended, usually increases with shorter pulses. In this case, an optimum can be found, in which the necessary field strength still very low compared to the CW radiation increases in order to achieve the same Abwehreffekt. The timing, ie the repetition rate of the pulses, and the Einkoppelfrequenz are to be selected according to the missile to be defended.

The disturbance ie defense of a missile by irradiation with frequency packets of the frequency f ₁ and a suitable pulse repetition rate has the advantage compared to a CW irradiation that, given a corresponding optimization with the same defense effect, a lower average power requirement is given. On the other hand, a slightly higher peak field strength is necessary at the destination and a slightly lower range is possible when the limit power of the radiation source is reached.

In continuous wave irradiation, ie in the case of CW irradiation or in the case of disturbance of the missile by irradiation with frequency packets, the dependence of the resonance frequencies of the missile on the angle of incidence is not resolved. Since the angle of incidence is not easily ascertainable, it is proposed, for example, to emit different frequency packets per cycle directly in succession. These frequency packets are suitably selected from previous coupling studies with different angles of incidence in order to obtain a good cross-section of coupling in at least one case, ie for at least one frequency. That is, instead of using frequency packets with a certain constant injection frequency, it may be advantageous to use frequency packets with changing coupling frequencies. These changes in Einkoppelfrequenzen can be done gradually or continuously. As an alternative to discrete frequencies, a so-called frequency sweep is also suitable. This frequency sweep is also suitably selected on the basis of the interaction data. The bandwidth and the sweep speed are kept relatively small in order to effectively couple in with regard to the width of the coupling-in resonance with sufficient irradiation time. If the sweep is too fast, the necessary field strength for disturbances would increase analogously to very short pulse durations. When irradiating a missile to be repelled with clocked frequency, ie pulse packets, each consisting of a frequency sweep, there is the advantage that with a suitable design, the knowledge of the Einkreiswinkels the missile is not necessary. However, the average power requirement is increasing.

According to the invention, it is furthermore possible for different frequency packets with mutually different pulse repetition rates to be used as electromagnetic interference radiation, the time windows determined by the pulse repetition rate of a first frequency packet being used for at least one second frequency packet. In this way, a disruption of several or different missiles by time-multiplexing of different missile-specific frequency packets is possible. If all frequencies for one type of missile or for groups of missiles at different angles of incidence (AOI) are covered, the pulsation with a first pulse repetition rate results in time gaps that can be used for other missiles. These time gaps are filled with at least one other frequency packet. The number of missiles to be controlled with different parameters is limited only by the time window that is available for fighting maximum. This variant of the method has the advantage that several missile types can be fought, whereby an identification of the different missile types is not required. However, this method according to the invention requires a high average power requirement; with a maximum utilization of the time gaps results in a power requirement which approximately corresponds to the power requirement of a continuous wave irradiation, as has been described above.

According to the invention, it is also possible to use parallel additive frequency packets with mutually different frequencies as the electromagnetic interference radiation. This is a disruption of several or different missiles by the parallel additive radiation of several different missile-specific frequency packets possible. Similar to the method according to the invention first described above, it is also possible according to the invention to emit the detected, missile-specific, optimal frequency packets in parallel and in addition. This has the advantage that a limitation to time gaps or to the available time window is avoided. It can therefore be irradiated in principle any number of different missiles. Additive frequency mixing makes it possible to combat several groups of missiles simultaneously. Of course, the power requirement of an amplifier increases since the maximum amplitude, ie field strength, can be two or more times the two individual amplitudes or several individual amplitudes. However, this approach has the advantages of being able to combat multiple types of missiles without the need to identify the different missile types. Another advantage is that there is no limit to the number of frequency patterns due to the distribution of time gaps.

The inventive system for carrying out the method according to the invention may be characterized in that an arbitrary waveform generator (AWG) and a number of parallel connected individual modules are provided, each having a phase shifter, an amplifier connected downstream of the phase shifter, an antenna downstream of the amplifier and the phase shifter have associated phase detector. Thus, the emission of high-power electromagnetic waves is possible, which cause by suitable radiated signal forms a mission foiling of one or more missiles simultaneously by disrupting its control and steering circuit electronics. Since the individual amplifier systems are limited in their maximum power, the invention strives for a phase-correct addition of several amplifier systems. The amplifiers and the antennas of the individual modules usually have a frequency- and amplitude-dependent phase shift between the input and the output, which can vary even between the respective amplifiers, the individual modules. When cascading amplifier antenna systems to influence manpads, however, a phase synchronization must be ensured at the respective antenna outputs. For this purpose, a phase control is realized between the respective amplifier input and the antenna.

The parallel connection of the individual modules enables increased power dissipation and greater profit. The necessary phase synchronism is achieved by a phase detector / phase shifter structure which equally regulates the phase between the antenna output signal and the AWG output. For this purpose, corresponding signals can be tapped directly on the antenna or on the respectively associated amplifier.

In the AWG different frequency bursts are output sequentially in the rhythm of the critical pulse repetition rate. This allows adaptation of the directional frequency selectivity of the target, i. Manpads. The limitation of the pulse repetition rate, the pulse length and the number of frequencies is defined by the finite time window mentioned above.

This system according to the invention has the advantage that only a single AWG or DDS synthesizer is necessary. The feedback single modules guarantee the phase equality, so that advantageously a simple parallel connection and coupling to the AWG is possible.

If an electrically controlled directivity is desired, this can be achieved via additional phase shifters i. Delay links are realized behind the AWG.

The need for a sequential arrangement of the sine functions in the AWG is based on the fact that the above-mentioned phase detector and phase shifter are only effective for a sine-time function. An extension of the system is based on a frequency separation of the antenna measurement signal and the AWG signal by means of bandpasses. In this case, a phase detection and correction is performed on the phase shifter for each filtered out frequency. In this way, a simultaneous addition of the frequencies to be emitted is possible, and a restriction with respect to a maximum available time window is eliminated.

The inventive system can also be realized in such a way that a number of parallel connected individual modules are provided, each having an AWG with integrated, multifrequency phase shifter, a downstream amplifier and a downstream antenna, the AWGs are synchronized via a master clock. In such an embodiment of the system according to the invention, the amplifier and the antenna system likewise have a frequency- and amplitude-dependent phase shift between the input and the output. This phase shift may also vary between the amplifiers. When cascading amplifier antenna systems to influence manpads, however, the respective antenna outputs must be in phase coincidence. For this purpose, a phase control d. H. Correction between an absolute reference phase of all AWGs and the respective antenna output in the AWG realized digitally.

The parallel connection of the individual modules enables increased power dissipation and greater profit. The necessary phase synchronism is achieved by a fully digitally implemented multi-frequency phase adaptation, which regulates the phase between the antenna output signal and the internal AWG frequency for all simultaneously output frequencies. All AWG 'are synchronized by a masterclock. In the AWG frequency bursts of different frequency are added up and in the rhythm of the critical Pulse repetition rate output. This allows an adaptation of the direction-dependent frequency selectivity of the target and the simultaneous fight against different targets. There is only a limitation of the number of different frequencies due to the maximum amplifier output power.

Further details, features and advantages of the invention will become apparent from the following description of the figures.

Figur 1

ein Energie-Zeit-Diagramm einer Bestrahlung mit Dauerstrich,

Figur 2

ein Energie-Zeit-Diagramm einer Bestrahlung eines Flugkörpers mit Energie-Pulsen,

Figur 3

ein Energie-Zeit-Diagramm einer Bestrahlung mit getakteten Energie-Paketen, die jeweils aus unterschiedlichen diskreten Frequenzen zusammengesetzt sind,

Figur 4

ein Energie-Zeit-Diagramm einer Bestrahlung mit getakteten Energie-Paketen, die jeweils aus einem Frequenzsweep bestehen,

Figur 5

ein Energie-Zeit-Diagramm zur Verdeutlichung einer sequentiellen Bestrahlung mit in der Frequenz und der Pulswiederholrate angepassten Parametern für unterschiedliche Flugkörper oder Flugkörper-Gruppen,

Figur 6

ein Energie-Zeit-Diagramm zur Verdeutlichung einer Bestrahlung mit in der Frequenz und der Pulswiederholrate angepassten Parametern für unterschiedliche Flugkörper oder Flugkörper-Gruppen im parallel additiven Modus,

Figur 7

eine Ausbildung des erfindungsgemäßen Systems mit einem AWG,

Figur 8

eine Erweiterung der Realisierungsmöglichkeit des Systems gemäß Figur 7, wobei nur ein Einzelmodul dargestellt ist, und

Figur 9

eine andere Ausbildung des erfindungsgemäßen Systems mit einer Parallelschaltung von Einzelmodulen, die jeweils einen AWG aufweisen.

Show it:

FIG. 1

an energy-time diagram of a continuous wave irradiation,

FIG. 2

an energy-time diagram of irradiation of a missile with energy pulses,

FIG. 3

an energy-time diagram of irradiation with clocked energy packets, each composed of different discrete frequencies,

FIG. 4

an energy-time diagram of irradiation with clocked energy packets, each consisting of a frequency sweep,

FIG. 5

an energy-time diagram for illustrating a sequential irradiation with parameters adapted to the frequency and the pulse repetition rate for different missiles or missile groups,

FIG. 6

an energy-time diagram to illustrate irradiation with parameters adapted to the frequency and the pulse repetition rate for different missiles or missile groups in the parallel additive mode,

FIG. 7

an embodiment of the system according to the invention with an AWG,

FIG. 8

an extension of the realization of the system according to FIG. 7 , where only a single module is shown, and

FIG. 9

another embodiment of the system according to the invention with a parallel connection of individual modules, each having an AWG.

FIG. 1 shows in an energy-time diagram, the irradiation of a manpad with continuous wave with an ideal for a specific missile to be defended missile f ₁ and the energy E ₀ . In the irradiation of a missile to be defended with a known, previously determined in laboratory experiments and with respect to the coupling of disturbances ideal frequency f _{1 of} the missile can be deflected from its trajectory. With such a continuous wave irradiation, the lowest field strength amplitude E ₀ is usually necessary at the target. Thus, the highest ranges can be achieved for a given transmission power and antenna configuration.

FIG. 2 illustrates in an energy-time diagram, the disturbance of a missile to be defended by irradiation with frequency packets of the frequency f ₁ and a suitable pulse repetition rate .DELTA.t. With Δt = 1 / f _PRR , where f _{PRR is} the respective timing, which is selected as the coupling frequency f ₁ missile specific. The field strength E ₁ required to defend a missile at the target usually increases with shorter pulses; However, an optimum can be found in which the necessary field strength E _{1 is} still very small in comparison to the field strength E ₀ for continuous wave irradiation (see FIG. 1 ) increases to achieve the same effect.

In continuous wave irradiation according to FIG. 1 and in a disturbance of the missile by irradiation with frequency packets of the frequency f ₁ and a suitable pulse repetition rate .DELTA.t the dependence of the resonance frequencies of the respective missile from the angle of incidence is not solved. Since the angle of incidence is not easily ascertainable, it makes sense, for example, to emit different frequency packets per cycle Δt directly following each other. These frequency packets are suitably selected from previous coupling studies with different angles of incidence in order to obtain a good cross section of coupling in at least one case - for at least one frequency. Is in FIG. 3 ₁ , which illustrates in an energy-time diagram the irradiation with clocked packets which are each composed of different successive discrete frequencies f ₁ , f ₁ , f ₁₊ . The pulse repetition rate .DELTA.t is according to FIG. 2 equal.

FIG. 4 illustrates in an energy-time diagram, the irradiation of a missile to be defended with clocked packets, each consisting of a frequency sweep f _1- ... f ₁₊ . That is, as an alternative to switched discrete frequencies f ₁ , f ₁ , f ₁₊ , a frequency sweep, ie a continuous frequency change, is also possible. This frequency sweep is selected appropriately based on the corresponding interaction data.

FIG. 5 illustrates in an energy-time diagram a sequential irradiation with parameters adapted in frequency and in the pulse repetition rate for different missiles or missile groups to be defended. If all frequencies for one type of missile or missile group are covered at different irradiation angles (AOI), the pulsation at a specific pulse repetition rate Δt ₁ in the corresponding time range results in time gaps which can be used for further missiles. These time gaps between the frequency packets f ₁ , f ₁ , f _{1 +} are filled with further frequency pulses f ₂ . The number of missiles to be controlled with different parameters is limited only by the said time window, which is the maximum available for combat.

The pulse repetition rate Δt _{2 of} the frequency packets f ₂ is determined by the pulse repetition rate Δt ₁ .

FIG. 6 illustrates irradiation with parameters adapted in frequency and in the pulse repetition rate for different missiles or missile groups in parallel additive mode. This prevents a limitation to gaps in the time domain, ie to an available time window. In principle, any number of different missiles can be irradiated in order to repel them. The FIG. 6 shows an embodiment of two missile groups, with the necessary frequency packets f ₁ and f ₂ temporally overlap. Due to additive frequency mixing, both missile groups can still be fought simultaneously.

FIG. 7 illustrates an inventive system 10 for defense against ground-to-air missiles (manpads), which represent a threat to military or civil aircraft at take-off and landing. The system 10 has an arbitrary waveform generator (AWG) 12 and a number of parallel-connected individual modules 14. Each individual module 14 has a phase shifter 16, a phase shifter 16 downstream amplifier 18 and an amplifier 18 downstream antenna 20. The respective phase shifter 16 is associated with a phase detector 22. Thus, an in-phase addition of a corresponding number of amplifier system is possible because the individual amplifier systems are limited in their maximum power. The amplifiers 18 and the antennas 20 usually have a frequency- and amplitude-dependent phase shift between the input and the output, wherein this phase shift can also vary between the individual amplifiers 18. In the cascading of amplifier antenna systems for influencing ie defending against manpads, however, it is necessary that a phase synchronization is ensured at the respective antenna outputs. For this purpose, a phase regulation takes place between the respective amplifier input and the antenna 20.

The parallel connection of the individual modules 14 allows increased power radiation and a larger antenna gain. The necessary phase synchronism is achieved by the phase detector / phase shifter structure which equally regulates the phase between the antenna output signal and the output of the AWG 12. For this purpose, the corresponding signals, for example, directly at the respective antenna 20 - or at the corresponding amplifier 18 - are tapped.

In the AWG 12, different frequency bursts are sequentially output in the rhythm of the critical pulse repetition rate Δt. This allows an adaptation of the direction-dependent frequency selectivity of a Manpads.

In the system 10 according to FIG. 7 if only a single AWG 12 or DDS synthesizer is needed.

The individual modules 14 are each connected in parallel to each other by means of a parallel phase shifter 28. The parallel phase shifters 28 are operatively connected to each other by means of frequency information from the AWG 12 processing common phase array controller 30.

FIG. 8 clarifies an extension of the system according to FIG. 7 , In this embodiment, an AWG 12 and a number of parallel-connected individual modules 14 are provided, of which in FIG. 8 only one is drawn. Each individual module 14 has a pair of parallel phase shifters 16, one for each Phase shifter 16 associated phase detector 22, one of the two phase shifters 16 downstream amplifier 18 and an amplifier 18 downstream antenna 20. The respective phase shifter 16 and the respectively associated phase detector 22 are each assigned a bandpass 24.

The need for sequencing the sine functions in the AWG 12 is based on the phase detector 22 and the phase shifter 16 being effective only for a sine-time function. The extension of the system according to FIG. 8 is based on a frequency separation of the antenna measurement signal and the AWG signal by means of bandpass filters 24, wherein for each frequency filtered out therefrom only the phase detection and correction takes place at the phase shifter 16. In this way, a simultaneous addition of the frequencies to be emitted is possible and there is no restriction on the maximum available time window. This is the in FIG. 6 clarified use case covered.

The FIG. 9 illustrates an embodiment of the system 10, wherein a number of parallel-connected individual modules 14 are provided, each having an AWG 12 with an integrated multifrequency phase shifter, the respective AWG 12 downstream amplifier 18 and the respective amplifier 18 downstream antennas 20, wherein the AWG's 12 are synchronized via a master clock 26.

The parallel connection of the individual modules 14 according to FIG. 9 allows increased power radiation and a correspondingly larger antenna gain. The necessary phase synchrony is achieved by a fully digitally realized multi-frequency phase adaptation, which regulates the phase between the output signal of the respective antenna 20 and the internal AWG frequency equally for all simultaneously emitted frequencies. In the AWG 12 frequency bursts of different frequencies are added up and output in the rhythm of the critical pulse repetition rate Δt. This allows an adaptation of the direction-dependent frequency selectivity of the missile to be defended and the simultaneous fight against different targets ie missiles.

List of reference numerals:

10

system

12

AWG / Arbitrary Waveform Generator (out of 10)

14

Single module (out of 10)

16

Phase shifter (from 14)

18

Amplifier (from 14)

20

Antenna (from 14)

22

Phase detector (for 16)

24

Bandpass (from 14)

26

Masterclock (from 10)

28

Parallel phase shifter

30

Phase array controller

Claims (3)

1. Method for defence against surface-to-air missiles which represent a threat to military and civil aircraft during takeoff and landing, the missile being jammed by irradiating it with electromagnetic jamming radiation in the form of a microwave radiation or a radio-frequency radiation, frequency packets with a defined pulse repetition rate being used as the electromagnetic jamming radiation,
   characterized in that frequency packets with injection frequencies that are varied in steps or varied continuously within the respective frequency packets are used, and the frequency packets looking alike among one another.
2. Method for defence against surface-to-air missiles which represent a threat to military and civil aircraft during takeoff and landing, the missile being jammed by irradiating it with electromagnetic jamming radiation in the form of microwave radiation or radio-frequency radiation, characterized in that
   frequency packets which differ from one another and have pulse repetition rates that differ from one another are used as the electromagnetic jamming radiation, with the time gaps, which result from the pulse repetition rate of a first frequency packet, being used for at least one second frequency packet.
3. Method for defence against surface-to-air missiles which represent a threat to military and civil aircraft during takeoff and landing, the missile being jammed by irradiating it with electromagnetic jamming radiation in the form of microwave radiation or radio-frequency radiation, characterized in that
   parallel additive frequency packets with frequencies which differ from one another are used as the electromagnetic jamming radiation with frequency packets with different pulse repetition rates being used.

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