Abstract
Method and system of electronic countermeasure comprising an airborne RF and IR decoy, being an independent, autonomous flying body that flies on its own, using its own aerodynamics, rotatable blades and fins, being applied as protection against Radio Frequency (RF) and infrared (IR) threats. Such an aircraft decoy comprises a body; a rotatable blade or vane disposed on the body; a power source capable of generating electrical current in response to rotation of the blade or vane; a wideband radar jammer responding to a radar signal with a wideband phantom radar signature corresponding to a phantom target; corner reflectors generating strong radar reflections corresponding to the phantom target; and an infrared source emitting a phantom infrared signature corresponding to a heat signature of the phantom target. Data stored within the decoy is destroyed automatically upon impact.
Claims
1. An active decoy comprising: a deployable body; at least one rotatable blade or vane disposed on the body; a power generator disposed in the body and coupled to receive rotational torque from the at least one rotatable blade or vane, the power generator configured to generate electrical current in response to the rotational torque; and at least one of the following: (a) a radar spoofing circuit disposed in the body, the radar spoofing circuit responding to a received radar signal with a phantom radar signature corresponding to a phantom target; (b) corner RF reflectors disposed on the body, the corner reflectors generating strong radar reflections; and (c) an infrared emitter disposed on the body, the infrared emitter emitting a phantom infrared signature corresponding to a heat signature of the phantom target.
2. The active decoy of claim 1 wherein the rotatable blade or vane is foldable into or onto the body.
3. The active decoy of claim 1 further including at least one angle-of-attack fin configured to at least in part counteract a rotational moment produced by the rotatable blade or vane.
4. The active decoy of claim 1 further including a variable electrical load selectively coupled to the power generator, and a circuit connected to control the variable electrical load to select a counter rotational torque the power generator applies to affect rotation of the body.
5. The active decoy of claim 1 wherein the body comprises a rectangular prism or cuboid dimensioned to be one inch by two inches by eight inches.
6. The active decoy of claim 1 wherein the infrared emitter comprises an array of infrared light emitting diodes disposed on at least one outer surface of the body.
7. The active decoy of claim 6 further including a controller connected to animate the array with a changing infrared light show emulating a heat signature of a phantom target.
8. The active decoy of claim 1 further including an inertial sensor that detects a ground strike and in response thereto, erases data stored within the body.
9. The active decoy of claim 1 wherein the radar spoofing circuit comprises at least one delay line that delays a received radar signal before retransmission.
10. The active decoy of claim 9 wherein the radar spoofing circuit further comprises a frequency shifter that frequency shifts the received radar signal to correspond to a negative doppler shift.
11. The active decoy of claim 1 wherein the corner RF reflectors return a radar signal with a radar cross section return signal close to that of a phantom target at low radar cross section.
12. An active decoy comprising: a deployable housing; at least one rotatable blade or vane disposed on the housing; a power generator disposed in the housing and coupled to receive rotational torque from the at least one rotatable blade or vane, the power generator configured to generate electrical current in response to the rotational torque produced as the active decoy follows a ballistic trajectory through the air; and a spoofing emitter disposed in or on the housing, the spoofing emitter emitting a spoofing signature of a phantom target.
13. The active decoy of claim 12 wherein the spoofing emitter comprises a radar spoofing circuit responding to a received radar signal with a phantom radar signature.
14. The active decoy of claim 12 wherein the spoofing emitter comprises corner RF reflectors disposed on the housing, the corner reflectors generating strong radar reflections.
15. The active decoy of claim 12 wherein the spoofing emitter comprises an infrared emitter disposed on the housing, the infrared emitter emitting a phantom infrared signature corresponding to a heat signature of the phantom target.
16. The active decoy of claim 12 wherein the housing comprises a cuboid dimensioned to fit into a conventional countermeasure magazine.
17. The active decoy of claim 12 further comprising at least one controller configured to self-destroy data stored in the housing upon detecting impact of the housing.
18. The active decoy of claim 12 further comprises a control circuit that selects a variable electrical load for the power generator to thereby control the rate of rotation of the housing.
19. The active decoy of claim 12 further including a charge storage device connected to the power generator and to an inductive charging interface.
20. The active decoy of claim 12 further including a navigation and communication device within the housing, the navigation and communication device configured to wirelessly communicate position and/or orientation information.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Example non-limiting embodiments include the following:
[0013] FIG. 1 shows an example decoy deployed by a fighter jet.
[0014] FIG. 1A shows a perspective view of an example non-limiting electronic countermeasure system for deployment by and use in/with aircraft.
[0015] FIGS. 2A, 2B exemplify respectively the folding/folded position (e.g., for storage in the aircraft magazine) and the unfolding/unfolded position of rotatable blades or wind vanes (e.g., for deployment after being expelled by the aircraft).
[0016] FIG. 2C shows an example conventional magazine for stowing and deploying decoys.
[0017] FIG. 3 illustrates a block diagram of the electronic countermeasure system and its interface with an external system such as a laptop computer.
[0018] FIG. 4 is a block diagram of an example generator and speed (fall characteristic) controller.
[0019] FIG. 5 is a block diagram of an example power supply, including interface for external induction power load.
[0020] FIG. 6 illustrates a block diagram of an example external communication block, including the external communication interface by induction.
[0021] FIG. 7 is a block diagram of an example light generator block in the infrared and thermal range with the controller of the light emitting diodes and the respective light emitting diodes in the infrared and thermal range.
[0022] FIG. 8 is a block diagram of an example radar jamming block with controller and sub-bands with respective receive and transmit antennas for different frequency bands.
[0023] FIG. 9 is a flowchart of example active operations of decoy 10 upon deployment.
DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS
[0024] The mentioned objectives, as well as others, are achieved by an Electronic Countermeasure System for use in Aircraft in the form of an airborne RF and IR decoy. The electronic countermeasure is a decoy with active RF, passive RF and IR subsystems that aims to attract incoming missiles, thus keeping the crew and aircraft safe. Being an independent, autonomous flying body, the countermeasure flies on its own, using its own aerodynamics, being applied as protection against Radio Frequency, RF, and infrared, IR threats to aircraft other than the decoy.
[0025] Example embodiments provide an active decoy comprising: a deployable body; at least one rotatable blade or vane disposed on the body; a power generator disposed in the body and coupled to receive rotational torque from the at least one rotatable blade or vane, the power generator configured to generate electrical current in response to the rotational torque; and at least one of the following: [0026] (a) a radar spoofing circuit disposed in the body, the radar spoofing circuit responding to a received radar signal with a phantom radar signature corresponding to a phantom target; [0027] (b) corner RF reflectors disposed on the body, the corner reflectors generating strong radar reflections; and [0028] (c) an infrared emitter disposed on the body, the infrared emitter emitting a phantom infrared signature corresponding to a heat signature of the phantom target.
[0029] The active decoy may have a rotatable blade or vane that is foldable into or onto the body and/or may further include at least one angle-of-attack fin configured to at least in part counteract a rotational moment produced by the rotatable blade or vane.
[0030] A variable electrical load selectively coupled to the power generator may be controlled by a circuit to select a counter rotational torque the power generator applies to affect rotation of the body.
[0031] The body may comprise a rectangular prism or cuboid dimensioned to be one inch by two inches by eight inches.
[0032] The infrared emitter comprises an array of infrared light emitting diodes disposed on at least one outer surface of the body.
[0033] A controller may be connected to animate the array with a changing infrared light show emulating a heat signature of a phantom target.
[0034] An inertial sensor may detect a ground strike and in response thereto, erases data stored within the body.
[0035] The radar spoofing circuit may comprise at least one delay line that delays a received radar signal before retransmission.
[0036] The radar spoofing circuit may further comprise a frequency shifter that frequency shifts the received radar signal to correspond to a negative doppler shift.
[0037] The corner RF reflectors may return a radar signal with a radar cross section return signal close to that of a phantom target at low radar cross section.
[0038] In another embodiment, an active decoy comprises a deployable housing; at least one rotatable blade or vane disposed on the housing; a power generator disposed in the housing and coupled to receive rotational torque from the at least one rotatable blade or vane, the power generator configured to generate electrical current in response to the rotational torque produced as the active decoy follows a ballistic trajectory through the air; and a spoofing emitter disposed in or on the housing, the spoofing emitter emitting a spoofing signature of a phantom target.
[0039] The spoofing emitter comprises a radar spoofing circuit responding to a received radar signal with a phantom radar signature and/or corner RF reflectors disposed on the housing, the corner reflectors generating strong radar reflections and/or an infrared emitter disposed on the housing, the infrared emitter emitting a spoofed infrared signature corresponding to a heat signature of the phantom target.
[0040] The housing may comprise a cuboid dimensioned to fit into a conventional countermeasure magazine.
[0041] At least one controller may be configured to self-destruct data stored in the housing upon detecting impact of the housing.
[0042] A control circuit may select a variable electrical load for the power generator to thereby control the rate of rotation of the housing.
[0043] A charge storage device may be connected to the power generator and to an inductive charging interface.
[0044] A navigation and communication device within the housing may be configured to wirelessly communicate position and/or orientation information.
Example Non-Limiting Subsystems (which May be Included in any Combination)
[0045] The Active RF type subsystem, called radar jammer or spoofer, operates in the UHF to W-band range, equivalent to the NATO standard bands B to M, so that it captures the enemy radar signal, changes amplitude, phase and delay and transmits the signal back convincingly as a phantom target that cannot be distinguished from a legitimate signal reflected by the real target. The technical solution used is based on a delay line.
[0046] The Passive RF Subsystem, called a reflector arrangement, is composed of corner reflectors that are added to the controlled rotation of the decoy on its own axis caused by the blades/wind vanes and fins interacting with the air the falling decoy is falling through, and provides a reflection of the signal, confusing the enemy radar. Corner reflectors generally consist of two or three electrically conductive surfaces which are mounted crosswise (e.g., at an angle of exactly 90 degrees), that have the effect of backscattering incoming electromagnetic waves by multiple reflection accurately in the direction from which the incoming waves come. They thus provide strong reflections to radar that are disproportionate to their size, making the reflected signature appear to come from a much larger object (e.g., a fighter aircraft rather than a small decoy).
[0047] The IR-type LED subsystem, called a light generator in the infrared and thermal range, is composed of one or more arrays of light emitting diodes (LED) that transmit a frequency spectrum similar to the heat radiation of the real target's engine, confusing the sensors of heat-guided missiles. The IR-type subsystem can be programmed in some embodiments to nearly exactly match the spectral frequency-power distribution of the target aircraft's engines, making it difficult or impossible for the enemy detection system using infrared spectral frequency analysis to distinguish the decoy's IR emissions from nozzle and exhaust IR emissions of the target aircraft's engines.
Example Form Factor of Decoy
[0048] The decoy (FIG. 1, 1A, item 10) is an airborne RF and IR decoy comprising an independent, autonomous flying body 12 that flies on its own, using its own aerodynamics and blades/vanes 16. It provides protection against RF and IR threats.
[0049] As shown in FIG. 1A, decoy 10 in one embodiment comprises an elongated housing 14 that may be roughly rectangular (rectangular prism or cuboid shaped) and have a form factor that enables the decoy to be launched by some kinds of conventional chaff and/or flare launching devices. Different aerodynamic designs are possible, potentially including some with wings, airfoils, etc.
[0050] In one embodiment, decoy 10 includes foldable/unfoldable blades/wind vanes 16 and foldable/unfoldable navigation (angle of attack) fins 18 disposed on an end of housing 14. The blades/vanes 16 (FIGS. 1, 2A, 2B) can be fixed-pitch and counter-rotating according to the best application for the dedicated scenario. The blades/vanes 16 and navigation (angle of attack) fins 18 may be folded (see FIG. 2A) into slots or grooves defined in housing 16 for compact storage of the decoy such as in an MJU-11 chaff/flare magazine such as shown in FIG. 2C, and unfolded (see FIG. 2B) when the decoy is deployed. One example dimensions can be 205 mm in length, and 25 mm52 mm width/depth (i.e, 0.1 inch by 2 inches by 8 inches), but any desired dimensions can be used.
[0051] As noted above, some embodiments of decoy 10 have a form factor that makes them compatible with preexisting (or newly designed) countermeasure launch magazines such as shown in FIG. 2C so an aircraft can launch many decoys (possibly intermixed with conventional flare and/or chaff countermeasure deployments) in rapid succession to provide active phantom targets for missiles. In particular, FIG. 2C shows a conventional magazine providing an array of chambers into which many active decoys 10 can be inserted. Conventional mechanisms may be used to automatically deploy the decoys from the magazine to exit through a door in the aircraft fuselage. Each decoy can detect (e.g. based on internal inertial sensing) that it has been deployed and may rapidly, automatically unfold and extend its blades/vanes 16 and fins 18. The aircraft crew can use such magazines to launch many decoys together or in succession to provide continuous protection against missiles and other attacks. Mission ballistic trajectories of the different decoys are totally up to the crew on the aircraft evading attack, and different decoys can thus be programmed differently before deploying them as countermeasures in a particular attack.
Example Block Diagram of Decoy
[0052] FIG. 3 is an example schematic block diagram of decoy 10. As FIG. 3 shows, decoy 10 may include a blades/generator 200, a power supply 300, external communication and navigation 400, an active radar jamming arrangement/circuit (Active RF type subsystem) 600, an active IR LED array arrangement (light generator in the infrared and thermal range) 500, and a reflector arrangement (Passive RF type subsystem) 700.
[0053] In one embodiment, the power supply 300 and external communications and navigation block 400 can interact wirelessly (e.g., via induction so that the decoy housing may be hermetically sealed) with a laptop computer 21 via a laptop interface 20, allowing the laptop computer to be used to program functions of the decoy. The inductive adapter (FIGS. 3-20) is a portable item that provides means for the operator to access the decoy (FIGS. 3-10) data easily and without the need to remove the load (decoy) from the magazine, and can be reconfigured by the laptop (FIGS. 3-21) on the track during the procedures of pre-flight. The laptop 21 can store configuration data including but not limited to data representing/controlling radar and IR signatures of a phantom aircraft into the internal memory device(s) of decoy 10, thereby configuring the decoy to generate such radar and IR signatures when it is deployed.
Example Decoy Power Generating System
[0054] The decoy 10 is provided with a generator (FIGS. 4-200) which converts the rotational movement of the fixed pitch blades or vanes (FIGS. 4-200) into energy for the power supply (FIGS. 5-300). The generator (FIGS. 4-200) works together with the system that controls the rotation of the decoy during its fall (descent). The generator (FIGS. 4-250) is driven by the blades or vanes 16 to generate e.g., AC current, and supplies this AC current to the rectifier (FIGS. 5-310) which converts the generated current to DC current. The rotation controller (FIGS. 4-210) works to keep the descent rotation at a constant value, which can be zero (no rotation) or may be set to a value of interest. A comparator (FIGS. 4-220) verifies the accelerometer 350 data that comes over the internal network within the decoy 10 against the desired rotation configuration. This comparator 220 controls a bank of transistors (FIGS. 4-230) which in turn release current to a bank of resistors (FIGS. 4-240). The blades or vanes 16 rotate to one side (direction) during descent as wind causes them to rotate, and the body tends to rotate the other way due to the angle of attack position of the fixed fins 18. The blades or vanes 16 and the fins 18 thus tend to cancel out each other's rotational moments so the decoy 10 can follow a ballistic trajectory without rotation or with a specific amount of rotation in a specified direction (e.g., if needed for phantom target emulation). In one embodiment, control is carried out in such a way that the torque on the rotatable shaft connecting the generator to the vanes/fins is sufficient to satisfy the rotation configuration of the decoy (FIGS. 3-10), dosing the counter torque of the generator shaft and keeping the fall within previously configured rotation parameters (in other words, the amount of current drawn from the generator can in turn vary the amount of counter torque the generator applies to the shaft to thereby control how much rotational force the blades/vanes 16 apply to the generator and thus to the body of decoy 10). The balance between torque and counter-torque is maintained throughout the fall by adjusting the resistance of the resistor bank, making adjustments to the resistance power consumption, added to the power consumption of the embedded systems, of the energy generated. In one embodiment, the generator is thus able to generator more current than the decoy 10's embedded active systems need to operate, with the resistor bank described above providing an adjustable (programmable) load for the excess current, in order to control decoy body rotation rate.
[0055] In one embodiment, a use of the blades or vanes 16 may be to power the generator 200 and thus ensure the decoy is powered for the entirety of its freefall (ballistic trajectory) before striking the ground. In such an embodiment, blades or vanes 16 do not necessarily function like a self propeller in order to change direction of the decoy as it freefalls, but rather serve as an extra power generator. Wind resistance offered by the blades or vanes 16 may however aerodynamically slow the rate of descent of the decoy 10 so it remains in the air longer.
[0056] The power supply (FIGS. 5-300) provides electricity for all internal sub-assemblies of the Decoy 10 including external communication and navigation (FIGS. 6-400), radars (FIGS. 8-600) and light emitting diodes (FIGS. 7-500). As noted above, the power supply (FIGS. 5-300) has an interface with the outside world through the induction adapter (FIGS. 2-20) and can also be charged through this channel. The Power Supply block (FIGS. 5-300) has a charger rectifier (FIGS. 5-340) in which it is possible to carry out short-term battery charging (360) via electromagnetic induction (FIGS. 5-341). The short-life battery (FIGS. 5-360) (which in some embodiments can be a capacitor or other charge storage device as opposed to a rechargeable battery) can also be charged with the surplus energy generated by the blades/vanes 16 and generation system (FIGS. 4-200) during the operation of the decoy. The short-term battery (FIGS. 5-360) acts as a supplementary power supply for the entire system, being responsible for providing energy during the first moments of activation of the decoy as well as in the event of a failure of the primary power generated by the generator (FIGS. 4-250).
Inertial Sensing System
[0057] The Accelerometer (FIGS. 5-350) when detecting a sudden acceleration change, characterized as the launch of the decoy (FIGS. 3-10; FIG. 9, 1000), will send a pulse to the controller (FIGS. 5-320) and only then will the controller (FIGS. 5-320) activate the entire decoy power system (FIGS. 3-10; FIG. 9, 1002), which remains at rest to save energy. The accelerometer (350) is also responsible for providing data to the controller (FIGS. 5-320) so it can detect when there is no more acceleration after the launch and thus perform the procedure of erasing all data from the internal memory, also called zeroizing, sending a pulse to erase all data from the decoy (10) after it touches on the ground when ejected (FIG. 9, 1010). This zeroizing prevents an attacker from gaining any useful information e.g., concerning phantom signature data from examining or reading out the internal memory. In one embodiment, decoy 10 is not designed to be recovered, but rather is expended and damaged or destroyed upon striking the ground.
External Communication and Navigation System
[0058] The external communication and navigation interface (FIGS. 6-400) interfaces with the external world through the induction adapter (FIGS. 3-20), being able to receive programming data made in a dedicated software installed in the laptop (FIGS. 3-21), the connection between the induction adapter (FIGS. 3-20) and the laptop 21 (FIGS. 3-21) being made via a USB or other conventional communications port or connection. The communication and navigation interface 400 can (wirelessly) report sensed parameters of an inertial sensor 430 such as a gyroscope, accelerometer, etc. in a way that is not a tell for the enemy's detection systems. The external communication and navigation unit (FIGS. 6-400) has an external communication interface (FIGS. 6-420) via magnetic induction (FIGS. 6-421) in which it is possible to load mission data from an external computer to the decoy (FIGS. 3-10). Its inertial unit (FIGS. 6-430) provides geolocation data and elevation and azimuth coordinates which are used by the controller (FIGS. 6-410) for greater effectiveness of the decoy (FIGS. 3-10) in suppressing threats. As noted above, the controller (FIGS. 6-410) (which may execute instructions representing the FIG. 9 flowchart) uses the inertial unit data to send the zeroize pulse to erase all data from the decoy after it touches on the ground when being ejected.
Phantom Optical Infrared Target Emulation
[0059] The array of LEDs 500 provides an infrared signature that emulates the engine exhaust/engine nozzle heat characteristics and/or other heat characteristics of a predetermined or specified phantom target, in order to confuse/distract an enemy (e.g., heat seeking missile) into attacking the phantom target instead of an actual airborne target such an aircraft that deployed the decoy.
[0060] In one embodiment, the array of light emitting diodes (FIGS. 7-500) operates in the IR range of wavelengths between 0.7 m-20 m, presenting the same spectrum and thermal intensity caused by the phantom target aircraft's engines. These items are customized in the programming (FIGS. 3-21) according to the particular phantom target aircraft so the IR spectral signature of the LEDs matches the IR spectral signature of the exhaust of the particular type of phantom target aircraft such as the actual aircraft from which decoy 10 is deployed. The same decoy 10 launched from any of different aircraft can thus be custom programmed to emulate the IR exhaust plume heat signature of the actual aircraft from which it is launched or any other desired phantom target. See for example Haq et al, Parametric design and IR signature study of exhaust plume from elliptical-shaped exhaust nozzles of a low flying UAV using CFD approach, Engineering Volume 13, 100320 (March 2022), https://doi.org/10.1016/j.rineng.2021.100320; Liu et al, A Simulation Method of Aircraft Infrared Signature Measurement with Subscale Models, Procedia Computer Science 1472-16 1877-(2019) for more information on exhaust nozzle and plume IR signatures of different aircraft.
[0061] Infrared and thermal light generator (FIGS. 7-500) presents the same spectrum and intensity (i.e., heat signature) of the thermal radiation caused by the phantom aircraft engines. The infrared and thermal light generator 500 comprises a network of infrared light emitting diodes or LEDs (FIGS. 7-520-1) (FIGS. 7-520-2) to (FIGS. 7-520-n) operating in the thermal and infrared spectral region, with a network or array of such light emitting diodes (FIGS. 7-520-1) (FIGS. 7-520-2) to (FIGS. 7-520-n) on each face of the Decoy (FIGS. 3-10). In one embodiment, the light-emitting diode network is made up of tens to thousands of light-emitting diodes, depending on the type of engine or engines on the phantom aircraft. Each LED in the array may provide a pixel that can be individually controlled in IR color (wavelength) and intensity. The light emitting diodes are tunable and controlled by current and voltage (and/or digital programming in some embodiments) through a processor and controller (FIGS. 7-510). The processor and controller receive information about the spectral range and intensity of infrared and thermal generation for a phantom target through the internal network of the decoy (FIGS. 3-10). Through the current and voltage control, the frequency, phase and intensity of transmission of each light emitting diode (FIGS. 7-520-1) (FIGS. 7-520-2) to (FIGS. 7-520-n) can be adjusted to provide an animated (changing) pattern that emulates the dynamic IR signature of the jet nozzle and plume of a phantom aircraft (which may match the actual aircraft the decoy is used to protect).
[0062] In one embodiment, the phase adjustment of each light emitting diode (FIGS. 7-520-1) (FIGS. 7-520-2) to (FIGS. 7-520-n) is provided top make it possible to control the elevation and azimuth direction of the main lobe of the light emitting diode networke.g., compensating for the momentary rotation in the azimuth direction and the change in inclination in the elevation direction (in polar coordinates) of the decoy (FIGS. 3-10) as detected by internal inertial sensor(s) described above. The processor and controller (FIGS. 7-510) can then adjust the frequency, elevation and azimuth angles, and beam intensity emitted by each face of the decoy system (FIGS. 3-10) independently in order to compensate for orientation changes of the decoy as it freefalls.
Passive Radar Reflectors
[0063] The array of reflectors (FIGS. 3-700) operates passively from 100 GHz-1 THz, consisting of several corner reflectors. The arrangement of reflectors (FIGS. 3-700), where each face of the decoy (FIGS. 3-10) has a corner reflector with an effective dimension proportional to the size of the respective face. The radar cross section, RCS, of the corner reflector is known and equal to: RCS [m2]=(4**a{circumflex over ()}4)/(3*lambda{circumflex over ()}2), or [0064] =(4a.sup.4)/(3.sup.2)
[0065] where a is the length of the corner of the reflector, lambda or A is the RF wavelength in meters, and RCS or is the radar cross section in square meters. In order not to exceed the dimension of the h face of the decoy, a shall be always smaller than h. The reflectors are thus designed to return radar signals in the same way an actual target would.
[0066] Thus, in one embodiment, the enemy radar will detect a target with RCS varying in the range of 0.03 to 0.49 m2 at 100 GHz and in the range of 3 to 49 m2 at 1 THz, being close to that of a fighter plane at low radar cross section.
Active Radar Jammer/Spoofer
[0067] Meanwhile, the decoy 10 provides radar jamming/spoofing operating in the band 400 MHz to 100 GHz through the use of, for example, 5 sub bands (FIGS. 8-610) (FIGS. 8-620) (FIGS. 8-630) (FIGS. 8-640) (FIGS. 8-650):
TABLE-US-00001 Operating Band Number Frequency Range operating: band 1 (FIG. 8-610) from 400 MHz to 1.2 GHz band 2 (FIG. 8-620) from 1.2 GHz to 3.6 GHz band 3 (FIG. 8-630) from 3.6 to 11 GHz band 4 (FIG. 8-640) from 11 GHz to 33 GHz band 5 (FIG. 8-650) from 33 GHz to 100 GHz
[0068] The 400 MHz to 100 GHz wideband can be covered by less than 5 or more than 5 sub bands with respective operating frequency ranges other than those mentioned above. In one embodiment, the decoy can be programmed to selectively turn on and off different operating bands to provide any desired frequency coverage for a radar return signature.
[0069] The array of radars (FIGS. 8-600) thus operates from 400 MHZ-100 GHz actively, composed of several internal subsets segregated by operating band, with an associated multiplicity of antennas (one receive antenna and one transmit antenna for each band), and with each internal subset operating independently. In one embodiment, the array of radars provides a radar return signature(s) matching the radar signature(s) and characteristic(s) of a phantom target moving from an enemy radar transmitter. The circuit is thus not necessarily jamming the enemy radar so it does not work, but instead is sending the enemy radar back a return (spoofed) radar signal that the enemy radar interprets as a legitimate return signal from an actual target whereas the signal is actually an artificially synthesized return signal intended to spoof or fool the enemy radar (which may be airborne in one embodiment), e.g., into indicating the phantom target has moved away whereas the actual aircraft is still closing toward the enemy radar position.
[0070] In one example embodiment, the radar jammer is based on an analog RF circuit(s) (and not a software defined radio) that receive the radar signal and retransmit it, analogically delayed and with the frequency shifted proportionally to the desired emulated target velocity doppler frequency. In one example embodiment of each radar jammer band circuit, the enemy radar signal enters the RX antenna (FIGS. 8-618), is amplified by the LNA low noise amplifier (FIGS. 8-616), passes through a multiplier/mixer (FIGS. 8-614) with the function of reducing the frequency of the signal carrier to a frequency compatible with that of an analog delay line (FIGS. 8-611). The delay line delays the signal by a fixed or programmable delay. The delayed signal is optionally sent to the multiplier/mixer (FIGS. 8-615), which in turn converts the delayed signal to the same carrier frequency as the incoming enemy radar signal and then this signal is amplified (FIGS. 8-617) and connected to the TX transmission antenna (FIGS. 8-619) or emission.
[0071] The reference frequency used in the two multipliers/mixers is generated by an amplitude-controlled oscillator (FIGS. 8-613), VCO, which is excited by a sawtooth voltage (FIGS. 8-612) and thus also produces a monochromatic signal, but with the frequency varying in the time also with a sawtooth history (FIGS. 8-612), that is, in a Delta_D time the frequency changes in Delta_f, which after reaching a maximum frequency returns abruptly to the minimum frequency. Both the voltage of the VCO (FIGS. 8-613) and the programming of the optional delay of the delay line are controlled by a microcontroller (FIGS. 8-660), which receives the operating instructions through the network bus of the decoy (FIGS. 3-10). In one embodiment, the delay line emulates a negative Doppler shift in the signal (i.e., a falling frequency such as you hear after a vehicle with a siren passes you and is now moving away from you), in such a way that the enemy radar will interpret that the phantom aircraft the decoy emulates is moving away from it.
[0072] In embodiments with a delay line that is programmable, its delay may also have a sawtooth history (FIGS. 8-612), emulating an increasing delay of the aircraft, due to its distance. Using a constant delay line (FIGS. 8-611), the enemy radar will already have negative Doppler information and will already interpret this information as a distance from the aircraft, without it noticing that the signal delay (i.e., the time of flight from when the radar signal is emitted and when an echo of the emitted signal is returned after being reflected from a target) is not changing. This approximation can be valid in many scenarios, as the lifetime of the decoy (FIGS. 3-10) once deployed is seconds. If the perfect emulation of the phantom aircraft is necessary, the programmable delay line (FIGS. 8-611) can be included, so that the enemy radar will receive both the Doppler and also the increase in the time of flight delay of the return signal encoding a decreasing distance between the radar transmitter and the phantom target, perfectly emulating the departure of the aircraft away from the attacker.
[0073] In one example embodiment, five independent blocks (FIGS. 8-610) (6 FIGS. 8-20) (FIGS. 8-630) (FIGS. 8-640) (FIGS. 8-650), each covering a different frequency range, operate simultaneously in their respective frequency range. This provides a wideband response. The generation parameters of the sawtooth waveforms (FIGS. 8-612) (FIGS. 8-622) (FIGS. 8-632) (FIGS. 8-642) (FIGS. 8-652) of the VCO (FIGS. 8-613) (FIGS. 8-623) (FIGS. 8-633) (FIGS. 8-643) (FIGS. 8-653) and the delay line (611) (621) (631) (642) (651) are externally programmed by the controller (FIGS. 8-660) and can be adjusted to the characteristics of the phantom aircraft employed. Such a wideband radar arrangement responds to radar signatures with a wideband radar response signature representing a phantom of the targeted aircraft.
[0074] The RX (FIGS. 8-618) (FIGS. 8-628) (FIGS. 8-638) (FIGS. 8-648) (FIGS. 8-658) and TX (FIGS. 8-619) (FIGS. 8-629) (FIGS. 8-639) (FIGS. 8-649) (FIGS. 8-659) antennas may for example comprise planar stripline or patch antennas that are distributed on the four faces of the decoy (FIGS. 3-10). The resulting irradiation diagram is omnidirectional in azimuth or horizontal and with a wide beam, with more than 60 degrees, in elevation or vertical, in such a way that the enemy radar can always illuminate and be illuminated by the decoy (FIGS. 3-10). Depending on the desired configuration, all or part of the sub bands can be active or not, depending on the pre-flight programming.
[0075] The controllers mentioned above (FIGS. 4-210, FIGS. 5-320, FIGS. 6-420, FIGS. 7-510, FIGS. 8-660) can be physically grouped in a single processing unit as well as being partially grouped in two, three, four or more networked processors according to better use of constructive resources.
OTHER EMBODIMENTS
[0076] Not all embodiments must include all components described above. For example, a first embodiment might include an active radar jamming circuit but no IR emitter array, whereas a second embodiment might include an IR emitter array but no active radar jamming circuit. Either the first or the second embodiment might include or not include the RF corner reflectors. A third embodiment meanwhile might include the RF corner reflectors but no active IR emitter array and no active radar jamming circuit. Either the first or the second or the third embodiment might include or not include the electrical generator and associated blades or vanes. Either the first or the second or the third embodiment might or might not include an internal inertial sensor and associated navigation and communications interface for reporting position for tracking purposes.
[0077] All patents and publications cited herein are incorporated by reference.
[0078] While the technology herein has been described in connection with exemplary illustrative non-limiting embodiments, the invention is not to be limited by the disclosure. The invention is intended to be defined by the claims and to cover all corresponding and equivalent arrangements whether or not specifically disclosed herein.\
