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#3735258 - 02/14/13 07:04 AM Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP)  
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This is the thread to discuss Electronic Warfare (EW), including Electronic Attack (EA) formally known as Electronic Countermeasures (ECM), Electronic Protection (EP) formally known as Electronic Counter-Countermeasures (ECCM) as well the theory and real world effectiveness/manifestation of the various techniques.


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
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#3735261 - 02/14/13 07:08 AM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Regarding EA & EP techniques solely in the radar spectrum, I wonder, how fluid is this tactical game between the two protagonists? In a dogfight for instance between two aircraft the situation is very dynamic, with move and counter move played out in quick succession.

With EW the following questions arise:

1) If my radar is being jammed or deceived (ignoring using other none radar methods of target tracking) what can be done, is a radar able to solve some of these problems or is it game over?

2) No radar is impervious to being jammed or deceived, if I discover during conflict that my opposition is exploiting weaknesses with characteristics of my radar, would this usually result in a hardware upgrade (e.g new antenna), software upgrade, both or it depends on techniques against me being used?

3) Assuming my radar is susceptible to velocity deception jamming from a particular aircraft, will that aircraft always enjoy a specific and fix probability of success against me or are there other variables at work meaning that sometimes its jamming/deceiving will not always be as effective?


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
#3735311 - 02/14/13 11:30 AM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Nice idea for a thread. I wish I knew more about the details behind various ECM and ECCM techniques.

Two videos that show the effect of jamming on the SA-3, and an upgraded SA-3.




Pretty cool to see what range-gate pulloff looks like to the radar operator. You can also see the slightly varying PRF to make jamming more difficult. Look at the tops of the radar displays, you can see the varying pulse rate.

Last edited by Mdore; 02/14/13 11:33 AM.
#3735344 - 02/14/13 01:30 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Mdore]  
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Originally Posted By: Mdore
Nice idea for a thread. I wish I knew more about the details behind various ECM and ECCM techniques.

Two videos that show the effect of jamming on the SA-3, and an upgraded SA-3.

Pretty cool to see what range-gate pulloff looks like to the radar operator. You can also see the slightly varying PRF to make jamming more difficult. Look at the tops of the radar displays, you can see the varying pulse rate.


Fantastic videos, thanks for posting them Mdore. thumbsup
I'll admit that I don't understand a few things going on there but it was great to see the system in action.


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
#3735448 - 02/14/13 05:55 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Originally Posted By: Wolfhound
Regarding EA & EP techniques solely in the radar spectrum, I wonder, how fluid is this tactical game between the two protagonists? In a dogfight for instance between two aircraft the situation is very dynamic, with move and counter move played out in quick succession.

With EW the following questions arise:

1) If my radar is being jammed or deceived (ignoring using other none radar methods of target tracking) what can be done, is a radar able to solve some of these problems or is it game over?

2) No radar is impervious to being jammed or deceived, if I discover during conflict that my opposition is exploiting weaknesses with characteristics of my radar, would this usually result in a hardware upgrade (e.g new antenna), software upgrade, both or it depends on techniques against me being used?

3) Assuming my radar is susceptible to velocity deception jamming from a particular aircraft, will that aircraft always enjoy a specific and fix probability of success against me or are there other variables at work meaning that sometimes its jamming/deceiving will not always be as effective?


There are several Jamming methods.
Some are effective against one type of radar system, while can be totally ineffective (even counter productive) against other SAM types.

The effectiveness of a Jamming method are depending on several factors including, Jammer plane aspect, Jammer/Radar operator proficiency, Jammer distance, etc...

There is no "Magic" jamming method, that could negate all SAM types.

Publicly available books are good references on this topic...
"Essentials of Electronic Warfare Book" is quite good,

also
"The History of U.S. Electronic Warfare Vol III"

is nice.

In this topic we will discuss some of the following techniques...

Denial Jamming:
- Barrage Noise Jamming
- Spot Noise Jamming
- Swept Spot Noise Jamming
- Cover Pulse Noise Jamming
- Modulated Noise Jamming

Deceptive Jamming:
- False Target Jamming
- Range Deception Jamming (Range Gate Pull Off)
- Angle Deception Jamming (Inverse Amplitude Modulation, Inverse Gain Jamming, Swept Square Wave
- Velocity Deception Jamming (Velocity Gate Pull Off, Doppler Noise, Narrow-band Doppler Noise, Doppler False Targets)
- Mono-pulse Deception Jamming (Cross Polarization Jamming, Cross Eye Jamming)


... and their effect of the systems depicted in the SAMSIM.
(In the future, it is a possible development direction, to add these advanced jamming methods into SAMSIM)


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

thumbsup
#3735456 - 02/14/13 06:12 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Originally Posted By: Wolfhound

I'll admit that I don't understand a few things going on there but it was great to see the system in action.


So why you don't asking? wink

#3735904 - 02/15/13 12:57 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Hpasp]  
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Originally Posted By: Hpasp
Originally Posted By: Wolfhound
Regarding EA & EP techniques solely in the radar spectrum, I wonder, how fluid is this tactical game between the two protagonists? In a dogfight for instance between two aircraft the situation is very dynamic, with move and counter move played out in quick succession.

With EW the following questions arise:

1) If my radar is being jammed or deceived (ignoring using other none radar methods of target tracking) what can be done, is a radar able to solve some of these problems or is it game over?

2) No radar is impervious to being jammed or deceived, if I discover during conflict that my opposition is exploiting weaknesses with characteristics of my radar, would this usually result in a hardware upgrade (e.g new antenna), software upgrade, both or it depends on techniques against me being used?

3) Assuming my radar is susceptible to velocity deception jamming from a particular aircraft, will that aircraft always enjoy a specific and fix probability of success against me or are there other variables at work meaning that sometimes its jamming/deceiving will not always be as effective?


There are several Jamming methods.
Some are effective against one type of radar system, while can be totally ineffective (even counter productive) against other SAM types.

The effectiveness of a Jamming method are depending on several factors including, Jammer plane aspect, Jammer/Radar operator proficiency, Jammer distance, etc...

There is no "Magic" jamming method, that could negate all SAM types.

Publicly available books are good references on this topic...
"Essentials of Electronic Warfare Book" is quite good,

also
"The History of U.S. Electronic Warfare Vol III"

is nice.

In this topic we will discuss some of the following techniques...

Denial Jamming:
- Barrage Noise Jamming
- Spot Noise Jamming
- Swept Spot Noise Jamming
- Cover Pulse Noise Jamming
- Modulated Noise Jamming

Deceptive Jamming:
- False Target Jamming
- Range Deception Jamming (Range Gate Pull Off)
- Angle Deception Jamming (Inverse Amplitude Modulation, Inverse Gain Jamming, Swept Square Wave
- Velocity Deception Jamming (Velocity Gate Pull Off, Doppler Noise, Narrow-band Doppler Noise, Doppler False Targets)
- Mono-pulse Deception Jamming (Cross Polarization Jamming, Cross Eye Jamming)


... and their effect of the systems depicted in the SAMSIM.
(In the future, it is a possible development direction, to add these advanced jamming methods into SAMSIM)

Ok, thanks. I'll look into getting those books you mentioned. I currently have EW 101: A First Course In Electronic Warfare so will have a look through that book also.


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
#3735951 - 02/15/13 02:35 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: piston79]  
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Originally Posted By: piston79
Originally Posted By: Wolfhound

I'll admit that I don't understand a few things going on there but it was great to see the system in action.


So why you don't asking? wink

Here goes then:

In the second video what was the Range Gate Pull Off impact, did it effect target tracking?
What is target 'Coherent Accumulator' & 'Wobble' modes?

I think it's perhaps time for me to dive into SAMSIM to get a better understanding. The Dvina is best for beginners right?


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
#3736134 - 02/15/13 06:42 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Originally Posted By: Wolfhound
...Here goes then:

In the second video what was the Range Gate Pull Off impact, did it effect target tracking?
What is target 'Coherent Accumulator' & 'Wobble' modes?


First, I am not a specialist, but I'll try...

Gate Pull Off:





On first one the real target was marked, on second - gate pull off efect... If "Pechora" goes for the bite, range boresight must go with the pull off (on the video you will see the left indicator that range doesn't change according the jaming efect..

On the second one - not sure but "Wobble" must reveal the false target (when jamming generates a lot false target in the boresight... don't know the english word for this jamming)..

#3736180 - 02/15/13 08:28 PM Electronic Warfare-1 [Re: Wolfhound]  
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As I promised, I will start a series from the available public sources, describing the development and methods of the EW (Electronic Warfare). We will concentrate on the EW against SAM systems available in the SAMSIM.

The first step is to understand the NATO frequency band allocation table:

Name, frequency wavelength SAM system component

A band 100..250MHz 3m..1.2m P12 (metric), P18 (metric), P14 (metric)
B band 250..500MHz 1.2m..0.6m
C band 500..1000MHz 60cm..30cm P15 (decimeter)
D band 1..2GHz 30cm..15cm
E band 2..3GHz 15cm..10cm SA1 (10cm), SA2A/B/F (10cm), SOC (10cm), SON4, SON9
F band 3..4GHz 10cm..7.5cm
G band 4..6GHz 7.5cm..5cm SA2C/E (6cm)
H band 6..8GHz 5cm..3.75cm SA4 (4cm), SA5 (4.5cm CW)
I band 8..10GHz 3.75cm..3cm SA3 (3cm), RPK-1
J band 10..20GHz 3cm..1.5cm ZSU-23-4 (2cm)
K band 20..40GHz 1.5cm..7.5mm
L band 40..60GHz 7.5mm..5mm
M band 60..100GHz 5mm..3mm


Last edited by Hpasp; 02/15/13 08:29 PM.

Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3736211 - 02/15/13 09:51 PM Electronic Warfare-2 [Re: Hpasp]  
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On 25 July 1965 an RB-66C ELINT aircraft monitoring the EOB (Electronic Order of Battle) of North Vietnam, located the following equipment...

Fire Control Radars
1 SCR-584
1 SON-4
21 SON-9
1 Fan Song

... thus the real Electronic Warfare battle started.

During the World War-II, US supplied some SCR-584 (10cm wavelength, E band) Conical Scanning AAA Fire Control radars to the Soviet Union.


The Soviet Union copied it under the SON-4 designation.


Its further developed and exported version, the SON-9 still kept the original EW properties (10cm wavelength, E band, Conical Scan).


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3736423 - 02/16/13 08:36 AM Electronic Warfare-3 [Re: Hpasp]  
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The SA-75MK Dvina (SA-2B/F) system used in North Vietnam had several components.

P-12 (Spoon Rest-A) target acquisition radar used the A band (VHF, metric wavelength).


RSNA-75M (Fan Song F) fire control radar used the same E band (10cm wavelength) as the AAA fire control radars, but it had a TWS (Track While Scan) target tracking method, using two separate antenna, that use two separate frequency.
It means from EW point of view, that you need to jam both flapping antenna beam at the same time.


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

thumbsup
#3736434 - 02/16/13 09:48 AM Electronic Warfare-4 [Re: Hpasp]  
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US aviation services (TAC, SAC, NAVY) used different ECM systems, with different methods.

TAC (Tactical Air Command) choice was the QRC-160-1 jamming pod.
It worked in the E band, and had four voltage tuned magnetron each delivering 100W frequency modulated continuous wave noise jamming. The propeller at the nose of the pod is a RAM air turbine, generating energy for its operation.
Its jamming frequency range was preset on the ground, the pilot had only an On/Off switch.


The Barrage Noise Jamming of the pod was used to deny the plane distance from the radar, while in angles (elevation, azimuth) it was still perfectly track able.

This method was perfectly working against the SON4/9 AAA fire control radar.
Without range information, they were unable to calculate the required firing lead angle.


Against the SA-75MK Dvina (SA-2B/F) this noise jamming created a vertical band on the screens.
The plane was trackable, missiles could be guided against it with T/T method, using 11sec (arm after launch) radio proxy fuse setting.


The TAC planes (F-105, F-4) used closed "jamming pod" flying formation to merge the vertical bands (of the separate planes) on the Dvina operator screen, to create one wide band, thus making precise angle tracking impossible.


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3736456 - 02/16/13 11:29 AM Electronic Warfare-5 [Re: Hpasp]  
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Instead of a jamming pod occupying weapon stations, the NAVY selected the AN/ALQ-51 Angle Deception Jamming system, that could be built into the already crowded airframe of the A-4, A-6, F-4, and F-8 planes.
This choice is limited the equipment electrical consumption, and the available space it could occupy.
It consisted of two suitcase sized boxes which had been installed in the A-4 gun can bay under the cockpit floor, limiting its ammo.

Inverse Amplitude Modulation was used against the SA-75MK Dvina (SA-2B/F) systems.
It radiated into the side-lobes of the radar, while the main-lobe left untouched.
At the Dvina operator screen, this technique resulted a "mustache" shaped target.
The automatic angle tracking would track the side of the "mustache" (where the target shape is widest) instead of the middle of the target causing miss, so the target had to be tracked manually.


Inverse Gain Jamming was used against the AAA SON-4 (Whiff) SON-9 (Fire Can) fire control radar systems.
During target tracking, the pencil beam of the antenna is conically scanned around the tracked target, mechanically. The target tracking system seeks to equalize the received signal strength during the rotation, thus centering the target.
The stronger jammer signal will lure the radar boresight away the target, eventually breaking its angle lock.

Last edited by Hpasp; 02/16/13 11:31 AM.

Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

thumbsup
#3736461 - 02/16/13 11:46 AM Re: Electronic Warfare-5 [Re: Wolfhound]  
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Tiny old black and white image of angle jamming. Awesome! I've been searching for images showing the effect of various jamming techniques. Thanks for posting.

Something I've wondered about though about SAM Simulator. Wouldn't very strong noise jamming cause multiple bands of noise on the radar display, as it receives noise in the side lobes as well as the main lobe?

#3736466 - 02/16/13 12:05 PM Re: Electronic Warfare-5 [Re: Wolfhound]  
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Frequency agile radar avoiding swept noise jamming.



And some EW Training software, mainly just a demonstration of the program, but it's kinda interesting anyway Tons of similar videos on the same channel.


Just thought I'd link in case anyone was interested. smile

#3736488 - 02/16/13 01:10 PM Re: Electronic Warfare-5 [Re: Mdore]  
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Originally Posted By: Mdore
Something I've wondered about though about SAM Simulator. Wouldn't very strong noise jamming cause multiple bands of noise on the radar display, as it receives noise in the side lobes as well as the main lobe?


We are still in 1965.
Modulated Noise Jamming will come a year later, with a different pod.
biggrin


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

thumbsup
#3736893 - 02/17/13 03:40 PM Re: Electronic Warfare-5 [Re: Wolfhound]  
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Great posts people very interesting! smile

The following pod is the QRC-160-8, better known as the AN/ALQ-87:

The pod contained pulse modulated and barrage noise jammers that operating in the following frequency bands:

E & F band - 2550Mc to 3650Mc - bandwidth 80 to 275Mc (adjustable)
G & H band - 4910Mc to 5110Mc - bandwidth 25 to 210Mc (adjustable)
*G & H band - 5350Mc to 5550Mc - bandwidth 25 to 210Mc (adjustable) *This is a training band compatible with the Fan Song C radar.
A band (153Mc - 157Mc) noise jammer operates simultaneously with the E & F band or G & H band units whenever a TWS radar signal is identified.

The pod operates in four different modes:

Mode A - 100W pulse noise 25 to 100Mc bandwidth - preset frequency - TWS only
Mode B - 300W pulse noise 25 to 100Mc bandwidth - preset frequency - TWS only
Mode C - 300W pulse noise 80 to 210Mc bandwidth - preset frequency - TWS only
Mode D - 300W pulse noise 80 to 210Mc bandwidth - or barrage noise 80/240Mc bandwidth - automatic - TWS & AA.

So the AN/ALQ-87 could simultaneously perform any two of three functions: denying range and azimuth data to Fire Can; depriving Fan Song of range, altitude and azimuth; and jamming the position beacon (down-link) in the sustainer section of the SA-2 missile. The latter down-link jamming was referred to as 'Special Jamming' and was very effective.


*********I have quite a large collection of Flight, Weapon Systems, Tactical & Supplementary Aircraft Manuals for Jets, Helicopters & some Props, spanning the Vietnam era to present. If you're interested in trading Flight Manuals, mainly for modern military aircraft, send me a PM.*********
#3737353 - 02/18/13 12:48 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Ive done some reading and this is what I found out about noise jamming.

Because noise jamming is range denying, to know how it works we have to know how radars measure range to target. Pulse radars sends energy in small packets many times a second and because of that they get their name. Also there are some terms to simplify things:
PW (Pulse Width - duration of each individual pulse transmitted, measured in microseconds [us]),
PRF (Pulse Repetition Frequency - number of pulses transmitted in a second),
PRI (Pulse Repetition Interval - time from begining of one pulse to the begining of the next one),
Max unambiguous range (Maximum range where a target can be located in a way that reflecting energy from a pulse is received before the next pulse is sent).

Range to target is calculated by measuring the time from transmitting the pulse to receiving reflected energy from the target. After that its easy math to calculate range:

R = (c * t)/2
c - speed of light, t - measured time


Radars maximum unambiguous range is dependent on its PRF, larger PRF results in shorter maximum (unambiguous) range and vice-versa.

Lets suppose we are in command of a pulse radar, we see a target inbound. We are happily transmitting radar energy towards the target on our radars PRF and see him nice and bright on the screen. He then activates his noise jammer. (Lets say his jammer is really simple, transmitting on same frequency as our radar and double our PRF). As our radar transmits a pulse and the pulse reaches the target, targets jammer transmits its own pulse, and just as the reflected+targets pulse reach half way between target and radar target transmits another pulse. So by the time we send the next pulse we have two separate pulses received. Resulting in two targets appearing on the screen. Now target switches its jammer to advanced mode (still simplified) resulting in increasing its PRF many times ourown. This results in our radar registering many targets along the same azimuth and elevation. When the PRF is increased enough to overcome resolution of the radar, all those targets meld into one continuous band of 'targets', making it impossible to track the target in range.

Now I still have a question. I read that radars can simply employ PRF filter thus ignoring most noise jamming. Radar will still process pulses of PRF equal to its own, but that just ads one more target, and if EWR or IADS is present it would practically eliminate the jamming completely. Now, how is it possible to go around that and still noise jam a pulse radar. Is it adding a possibility to change PRF on the fly, and not just set it to a fixed high value? Im sure that could confuse the radar computer.

Also if I got something wrong, please point it out.

#3737363 - 02/18/13 01:14 PM Re: Electronic Warfare (EW), including Electronic Attack (EA) & Electronic Protection (EP) [Re: Wolfhound]  
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Noise jammers don't transmit pulses, they transmit a continuous signal. There's no pulses you can filter.

A jammer that transmits a pulse based on the radar pulse is a deception jammer. It's used to create a false target. You already know this.

If the jammer emits pulses when the radar pulse hits it, and then slowly introduces a time delay pulse by pulse, it'll look like the target split in two. The real aircraft in front, and the fake jammer target behind.

If the radar uses a fixed PRF, then the jammer will know when the next pulse will arrive before it arrives, and so can transmit a jamming pulse before the radar pulse arrives. This also makes the target seem like it's split in two, but this time the closest target is the fake.

A radar can use jittering, where it varies it's PRF slightly pulse to pulse. This means the jammer will never know exactly when the next radar pulse will arrive, so can only produce fake targets behind the jammer, by starting a timer based on when the pulse arrives.

I think what you mean by PRF filtering, is a radar that uses jittering, and will only see targets which match the transmitted varying PRF.

Noise jamming just transmits a very powerful wall of noise, that covers the reflected signal, so range cannot be determined.

I should probably say I'm not an expert, so don't take what I say as law.

Last edited by Mdore; 02/18/13 01:34 PM.
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