RF decoy and method for deceiving radar-based missiles

• US 8,049,656 B2
• Filed: 07/09/2007
• Issued: 11/01/2011
• Est. Priority Date: 10/26/2006
• Status: Active Grant

• Current Assignee: RST REUT Systems and Advanced Technologies Limited
• Original Assignee: RST REUT Systems and Advanced Technologies Limited
• Inventors: Cohen, Avraham, Amarant, Arye, Shani, Moshe, Levine, Ely
• Primary Examiner(s): LOBO, IAN J
• Application Number:
  US11/774,832
• Publication Number:
  US 20080198060A1
• Time in Patent Office: 1,576 Days
• Field of Search: 342/9, 342 12- 14, 455/1
• US Class Current: 342/14
• CPC Class Codes: F41H 11/02 Anti-aircraft or anti-guided missile or anti-torpedo defence installations or systems cartridges or missiles for producing smoke or for dispensing radar chaff or infrared material F42B5/15, F42B12/48, F42B12/70; informative reference: details of radar or sonar systems G01S7/00; jamming or electronic countermeasures G01S7/38, G01S7/495, H04K3/00
• CPC Class Codes: F41J 2/00 Reflecting targets, e.g. radar-reflector targets; Active targets transmitting electromagnetic or acoustic waves
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: G01S 7/38 Jamming means, e.g. producing false echoes
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons
• CPC Class Codes: H01Q 1/286 substantially flush mounted with the skin of the craft
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

An expendable, stand-alone, off-board Electronic Counter-Measure system, airborne RF decoy aimed to provide airborne platforms with protection against multiple radar-based threats including Air-to-Air and Surface-to-Air missiles both active and semi-active ones. The airborne RF decoy has the mechanical outline of standard chaff and flare decoys and is safely ejected from any platform by pyrotechnic elements. The airborne RF decoy deceives enemy radar-based threats as follows: immediately after its ejection from the protected airborne platform, the decoy activates an energy source, stabilizes its path, acquires illuminating signals and analyzes threat parameters. Then the decoy alters the received signals to generate an authentic false target and transmits a deceiving signal towards the radar threat. The radar threats locks on the decoy and follow its path. Thus the threat course is diverted from the protected airborne platform and a large miss distance of the attacking missile (tens to hundreds of meters) is assured.

Claims

1. A stand-alone airborne RF decoy adapted for protecting an airborne platform against multiple enemy radar-based threats, said airborne RF decoy comprising:

(i) means for receiving a plurality of radar signals from one or more directions;

(ii) means for storing said plurality of radar signals;

(iii) means for analyzing said plurality of radar signals to identify threat parameters;

(iv) means for altering said plurality of radar signals in order to deceive said multiple enemy radar-based threats;

(v) means for transmitting the altered radar signals;

(vi) an independent power supply source;

(vii) an external form of a standard chaff decoy or a standard flare decoy so that the airborne RF decoy can be ejected from the airborne platform via a standard housing of chaff or flare dispensers; and

(viii) vertical and horizontal wings that are opened automatically immediately after ejection from the airborne platform, followed by a pyrotechnic mechanism that brings the wings to their final position so that the airborne RF decoy achieves aerodynamical stability.

2. An airborne RF decoy according to claim 1, wherein said means for transmitting the altered radar signals in said airborne RF decoy stops transmitting altered signals periodically and while said means for transmitting stops transmitting, said means for analyzing analyzes the received radar signals to confirm if each enemy radar-based threat still exists or if the previously identified threat parameters have changed.

3. An airborne RF decoy according to claim 1, wherein said means for receiving a plurality of radar signals are an omnidirectional antenna embedded inside the airborne RF decoy, said omnidirectional antenna being implemented without any erection mechanisms or moving parts.

4. An airborne RF decoy according to claim 3, wherein said embedded antenna takes the form of a small monopole, an array of two monopoles or a conformal array of three radiating elements when said antenna operates in a linear polarization.

5. An airborne RF decoy according to claim 3, wherein said embedded antenna takes the form of helical antennas when said antenna operates in a circular polarization.

6. An airborne RF decoy according to claim 1, wherein said threat parameters include:

frequency, bandwidth, transmission power, pulse repetition frequency (PRF), Doppler shift, low frequency modulation (LMF) of the RF signal, or any combination thereof.

7. An airborne RF decoy according to claim 1, wherein said airborne RF decoy is configured to be ejected from the airborne platform.

8. An airborne RF decoy according to claim 7, wherein said airborne RF decoy is ejected from the airborne platform via pyrotechnic dispensers.

9. An airborne RF decoy according to claim 7, wherein said airborne RF decoy is ejected from the airborne platform via a dedicated housing.

10. An airborne RF decoy according to claim 1, wherein said enemy radar-base threats include:

air-to-air missiles, air-to-air fire-control radars, surface-to-air missiles and surface-to-air and radars.

11. An airborne RF decoy according to claim 1, wherein said airborne platform includes:

fighter aircraft, wide-body transport aircraft, wide-body passenger aircraft, unmanned air vehicles, unmanned combat aircraft and balloons.

12. An airborne RF decoy according to claim 1, further including means to control the distance between said airborne RF decoy and said airborne platform.

13. An airborne RF decoy according to claim 12, wherein said means to control the distance include rocket propulsion.

14. An airborne RF decoy according to claim 13, wherein said distance between the airborne RF decoy and the airborne platform ranges from tens to hundreds of meters in both range and altitude.

15. An airborne RF decoy according to claim 1, wherein said airborne RF decoy operates within a broad spatial coverage of up to 360 degrees in azimuth and at least 90 degrees in elevation.

16. An airborne RF decoy according to claim 15, wherein the spatial orientation of the airborne RF decoy, after ejection from the airborne platform, is stabilized in the roll plane.

17. An airborne RF decoy according to claim 15, wherein the spatial orientation of the airborne RF decoy, after ejection from the airborne platform, is not stabilized in the roll plane.

18. An airborne RF decoy according to claim 1, further including means to communicate with the airborne platform.

19. An airborne RF decoy according to claim 18, wherein said means to communicate with the airborne platform include one or more of the following communication links:

(i) a wire or proximity link;

(ii) short-range wireless link; and

(iii) long-range wireless link.

20. An airborne RF decoy according to claim 1, wherein said airborne RF decoy operates in accordance with a pre-flight data instruction file.

21. An airborne RF decoy according to claim 20, wherein said pre-flight data instruction file is loaded by an external data loader via a dedicated connector that is embedded in the decoy, and data loading is done on the ground prior to the flight mission.

22. An airborne RF decoy according to claim 21, wherein said pre-flight data instruction file is updated before ejection by a wire/proximity link, after ejection via a short-range wireless link, via a long-range wireless link, or any combination thereof.

23. An airborne RF decoy according to claim 1, adapted to work together with electronic warfare and electronic countermeasure systems on board of said airborne platform.

24. An airborne RF decoy according to claim 23, wherein said airborne RF decoy and electronic warfare and electronic countermeasure systems on board of said airborne platform cooperate in the use of their jamming resources in order to prevent enemy radar-based threats to track the airborne platform.

25. An airborne RF decoy according to claim 23, including generation of combined synchronization between deceiving signals coming from the airborne platform and deceiving signals coming from the airborne RF decoy.

26. An airborne RF decoy according to claim 1, further including means for minimizing interferences between the airborne RF decoy and the on-board equipment of the airborne platform.

27. An airborne RF decoy according to claim 26, wherein said means for minimizing interferences include either blanking of said airborne RF decoy so it does not interfere with on-board equipment of the airborne platform when operation of said on-board equipment has higher priority;

or blanking of on-board systems of the airborne platform that interfere with said airborne RF decoy when operation of said airborne RF decoy has higher priority.

28. An airborne RF decoy according to claim 1, wherein said means for storing said plurality of radar signals are Digital Radio Frequency Memory.

29. An airborne RF decoy according to claim 1, further including means to automatically enter into an “

end of life”

mode with self-destruction capability and complete memory erasure of sensitive components.

30. An airborne RF decoy according to claim 1, wherein said airborne RF decoy is ejected automatically after an alert from a missile warning system on board of the airborne platform.

31. An airborne RF decoy according to claim 1, wherein said airborne RF decoy is ejected after a manual command of the airborne platform'"'"'s aircrew.

32. An airborne RF decoy according to claim 1, wherein said power supply is a standard alkaline battery or a thermal battery that is activated during ejection of said airborne RF decoy from the airborne platform.