Countermeasure against anti raditation misslie

[peterAustralia]

In recent times countries have spent big dollars on air defence systems, and then seen then be overrun.

Often air launched anti radiation missiles are used to attack a radar as soon as it is switched on.

As I underdstand it a radar is a radio beam transmitter, radio reciever and procesing unit. Would it be possible to cheaply build decoy radars to absorb anti radiation missiles, thus giving a chance for the real radars to do their work without getting destroyed

Obviously the decoy radar would not need a reciever, or processor. Now marine radars for yachts and such can be bought for under a $1000 (via a quick ebay search), thus making a radar on the cheap is possible. Making a decoy radar that appears like an air defence radar is obviously going to be harder. I would hazard a guess that an effective decoy could be built for a modest sum, say $20000. The tolerances need not be high, the quality need not be high, etc etc.

To be effective the decoys would be needed to be used in large numbers, probably the thousands. Logic suggests they would be much cheaper than the missile that attacks it.

Does anyone think that this idea is vaid? If I were to specualte about Iran or Iraq if we talk in past tense, it may be useful, might have been useful, to have such decoys by the thousand.

n peter evans

 

[Waylander]

The problem is that every radar has a special signature.

So for example there could be millions of cheap 1000€ radars but you would still be able to find the SA-6 between them.

 

[peterAustralia]

yes, I realise that,

Marine radar was just an example that a radar can be built cheaply. Am not advocating use of marine radars as decoys.

but I wonder on how expensive it would be for example to make a decoy that has the signature of the SA-6. Obvioulsy a lot lot less than a real setup. Would you be willing to specualte on how much such a decoy might cost.

 

[Waylander]

In the end it might be as expensive as a "real" radar.
It has to have the same buildup and the same signal strength so I cannot imagine were you really could save money.

 

[Ozzy Blizzard]

If they were all radiating on specific frequencies could you have indipendant reciever and prosessors. The could be usefull to counter LO aircraft as there being hot from all over the place. You would need thousands of ARM's to defeat the whole network. Although the transmiters would all have to be a bit more sophistocated and thus expensive.

 

[Waylander]

That might be.

In the end I am far away from having real knowledge in aviation terms so my comments were mostly pure speculation.

 

[Totoro]

What we need here is a relatively accurate breakdown of cost of a radar. How much does the array cost percentage wise? I would think the processing unit is priciest there, in the overall package. But if a radar system is, say, 10 million dollars, then having a 'decoy array' costing 2 million dollars wouldn't really be usable. One could strip down everything from the decoy, except the array itself. Power unit would be separate, and would not be hit when the array is hit, one'd only need to have spare power cables.

Key is not to have more decoy arrays in stock than enemy has ARMs in stock - but to have more decoys than enemy can put ARMs in the air, at any given moment in the war. The more ARMs enemy has to carry, the less true offensive weapons it has on that mission.

 

[Chrom]

What we need here is a relatively accurate breakdown of cost of a radar. How much does the array cost percentage wise? I would think the processing unit is priciest there, in the overall package. But if a radar system is, say, 10 million dollars, then having a 'decoy array' costing 2 million dollars wouldn't really be usable. One could strip down everything from the decoy, except the array itself. Power unit would be separate, and would not be hit when the array is hit, one'd only need to have spare power cables.

Key is not to have more decoy arrays in stock than enemy has ARMs in stock - but to have more decoys than enemy can put ARMs in the air, at any given moment in the war. The more ARMs enemy has to carry, the less true offensive weapons it has on that mission.

At least Russian have radar-decoyes in service. These things emulate size/IR/optical/radar signature of true radar and also emmits strong radar waves. It MIGHT be possible to distinguish a true radar from false throught carefull examination but certainly no missile can do that. These things costs like 1/100 of true radar/vehicle.
Also, ARM missiles are quite ineffective against fairly modern integrated AD network. FC radars useally switch on only for several seconds to guide missile before impact, and target aquision radars useally work in network so the radars most close to target are switched off and only radars what are out of threat continue working and supply target information for FC radars. It is also worth noting what average SAM missile 3 to 6 times faster than average ARM missile. The consequences are clear...

 

[Maskirovka]

Speaking of countermeasures. The serbs used a lot of low-tech, and successfully I might add, countermeasures against the NATO bombers. One thing that is rumoured was the use of ordinary microwave owens to confuse anti-radar missiles and NATO fighterplanes. True or not? I don´t know. In theory it could work tough IIRC...

 

[Waylander]

Our Tornade ECRs reported that they had not that much problems clearing corridors for the strike crafts either by destroying the sam/radar sites or by forcing them to shut down.
But it is right many of our HARMs went into the woods without hitting anything due to the fact that these versions were not able to remember the position of the shut down radar.

 

[dioditto]

In recent times countries have spent big dollars on air defence systems, and then seen then be overrun.

Often air launched anti radiation missiles are used to attack a radar as soon as it is switched on.

As I underdstand it a radar is a radio beam transmitter, radio reciever and procesing unit. Would it be possible to cheaply build decoy radars to absorb anti radiation missiles, thus giving a chance for the real radars to do their work without getting destroyed

Obviously the decoy radar would not need a reciever, or processor. Now marine radars for yachts and such can be bought for under a $1000 (via a quick ebay search), thus making a radar on the cheap is possible. Making a decoy radar that appears like an air defence radar is obviously going to be harder. I would hazard a guess that an effective decoy could be built for a modest sum, say $20000. The tolerances need not be high, the quality need not be high, etc etc.

To be effective the decoys would be needed to be used in large numbers, probably the thousands. Logic suggests they would be much cheaper than the missile that attacks it.

Does anyone think that this idea is vaid? If I were to specualte about Iran or Iraq if we talk in past tense, it may be useful, might have been useful, to have such decoys by the thousand.

n peter evans

Simple. Just have anti-anti-radiation-missile system in place too shoot down the missiles

Also, use AESA or PESA radar which has "Low probability of intercept". If system is done right, the aggressor wouldn't know the radar is even in their path.

Honestly, I think any well equiped technologically advanced country can always find ways shoot down invading planes better than the plane able to drop their bombs on them. The advantage is always on the defender side, because a plane, is a small package, it can only cram so much electonics plus fuels plus bombs plus the pilot... where as ground based system has no such limit. Again, I am assuming you are talking about two equally advanced country at war.

 

[Ozzy Blizzard]

How can AESA's have low detection probabilities if they are scaning? By definition every time a target is detected microwaves are hiting that target, thus allowing the target to detect the radar? I've heard this before and i'd love to know how ths works.

 

[dioditto]

How can AESA's have low detection probabilities if they are scaning? By definition every time a target is detected microwaves are hiting that target, thus allowing the target to detect the radar? I've heard this before and i'd love to know how ths works.

I think it works by switching frequency millions of time per second, with power just slightly above the threshold of the ambient noise. For the opposing system, they would have to differentiate these millions of signals mix with noise... thus almost impossible.

 

[crobato]

How do you define the siganture of an SA-6 radar? When radars are still like in the sixties and seventies, its probably a lot easier to read their signals.

but today's radars, often aided by PESAs and AESAs, or just solid state emitters, can use a whole variety of frequencies and modes of operation. They're quite flexible. If you set an ARM to home in one, it may change its operating mode, go null, change frequencies, go into LPI, or so on. An ARM chasing one signal is suddenly forced to confront a different signal, and yet it is not smart enough to distinguish what it is exactly.

If its an ECM rich environment, its easier to mask your signals amidst the ECM. If you shut it down as soon as an ARM is on to you, the ARM may suddenly be confronted with the ECM signals and may head at the jammer instead.

Another way is to blink the signals between two radar sets. If you shut down one and start the other, the ARM changes midcourse to chase t he second radar. Then you shut the second radar and restart the first, and the ARM change course again. Doing so, the ARM can run out of fuel. The ground jammers can also save themselves that way.

 

[Ozzy Blizzard]

but deosent the reciever have to do the same thing with the return signal??

 

[dioditto]

but deosent the reciever have to do the same thing with the return signal??

What do you mean??

Basically, the radar station that use AESA/PESA, knows before hand exactly what frequency it is sending out even though it's switching rapidly, and it knows the the exact sequence of these frequency change and parse that to the receiver so it knows what to look for when those signal bounce back.

The one that throws the ball knows exactly where the ball goes, what type of ball....

 

[Totoro]

It should also be pointed out that any kind of radar array can be used to switch frequencies rapidly, doesn't need to be phased array, as it is not a function of array itself but of the electronics behind the array.

What could be argued, however, is that AESA, unlike other arrays which have just one transmitter, could use its numerous transmitters to simultaneously transmit at different frenquencies. Downside of that, though, is that you could rob yourself of range, but in certain scenarios it is overall a good thing.

 

[chrisrobsoar]

It should also be pointed out that any kind of radar array can be used to switch frequencies rapidly, doesn't need to be phased array, as it is not a function of array itself but of the electronics behind the array.

What could be argued, however, is that AESA, unlike other arrays, which have just one transmitter, could use its numerous transmitters to simultaneously transmit at different frequencies. Downside of that, though, is that you could rob yourself of range, but in certain scenarios it is overall a good thing.

Mind if I jump in and offer a little help, I trained as a radar engineer before going into program management and I think that I still remember the basics.

Firstly the frequency transmitted can be changed over a narrow range of frequencies, say +-5/10% of the centre frequency, very rapidly without too much trouble. The antenna dimensions are determined by the frequency that is to be transmitted. For instance for a given antenna the beam width will be narrower at the high frequencies and wider at the lower frequencies.

The frequency also affects the matching which in turn affects the amount of energy transmitted and the amount of energy reflected back into the transmitter.

With modern conventional radars the transmitter is not the key element of the system that determines the frequency transmitted! The transmitter is operating as a power amplifier, the frequency that is transmitted is determined by the circuits that drive it and these are usually part of the receiver.

In these conventional radars the transmitter is a Travelling Wave Tube (TWT). This is coupled to the antenna via a circulator (a ferrite device that ensures that the power from the transmitter goes to the antenna and not back into the receiver). The returning energy is directed through the circulator to the receiver.

I could go on here to describe how Phased Arrays and Mechanically Scanned Arrays work, but I won’t.

Active Electronically Scanned Array (AESA) are comprised of many (thousands) of Transmit/Receive Modules T/R Modules. Each element is comprised of four major elements, an antenna, a circulator (to route the signals), a receiver low noise amplifier and a transmitter amplifier.

By changing the signals feeding these elements the resulting beam (or beams) can be steered as required.

However, as the distributed transmitter drive signals and the collated received signals all originate from the same source (in old terms the master oscillator) usually even a AESA radar cannot transmit different frequencies at the same time.

It is possible to switch the drive signals so that the some elements of the array can be driven by different sources, but the control is difficult and messy.

So called mixed- arrays (including T/R Modules for different frequency bands) have been developed so that secondary radar (IFF/SSR) can be incorporated into the primary radar antenna.

The bottom line is that at present the T/R Modules are all driven by a coherent signal, various fixed and variable phase shifts are introduced as necessary to scan the beam (or beams).

So far we have not been able to locate the component that determines the fundamental frequency in the T/R module, because instantaneously phase locking them has not been possible.

It is rather like the organic communications between a conductor and an orchestra.

Also like singing in a choir in order to partition the affects from adjacent cells some singers (AESA elements) may have to remain quite, so as not to interfere with neighbouring activities.

I am prepared to handle basic questions on radar, but if any post doctorial students require mentoring, my rates are reasonable. My background is mainly airborne interception radar (AI), but I have a grounding in missiles, ground radar and counter-measures (including IR & EO).

A problem with radar associated with Surface to Air Launched Missiles (SAM) and the counter, Anti-Radiation Missiles (ARM) is that anyone who knows a lot about this issue cannot talk about it.

I have specific expertise in areas that I cannot discuss in a public forum, but I do have more general knowledge that may be of assistance in other areas.



Chris

 

[LancerMc]

There are all kinds of crazy tricks you can play on radar in either direction. I once got the chance to handle the B-1B's towed radar decoy. It's small and very powerful from what the munitions guys told me. Basically something the size of a 20 oz Soda bottle can make radar screen think its another B-1B.

The systems that detect SAM radar frequencies are very secret. When I flew a B-1B full motion sim, the DWO screen was the only part of the entire cockpit I wasn't allowed to use or turn on. The Lt. Col wouldn't even discuss it with me and told us not to ask any question about it either.

 

[Ozzy Blizzard]

Thanx chris, thats an inforative post. But how does AESA radars achieve low probablility's of detection? Because of the constantly changing frequancy?