Russian Anti-Radiation Missiles

Yes, their western codenames are:

AS-17 Krypton : Kh-31

AS-12 Kegler : Kh-25MP

AS-11 Kilter : Kh-58



Basically they are light (Kh-25MP) and medium (Kh-31 and Kh-58) anti radiation missiles, with the light missiles being about 300-350kgs with a range of up to 40km, for use on fighter bombers and strike aircraft, and the medium missiles with a weight of about 600-700kgs and ranges from 120km to 250km depending on the model and launch platform/launch profile.

Performance wise there is not a huge difference between the Kh-31 and Kh-58, they are two different ways to achieve a similar solution. The Kh-58 is the older missile and it is still being updated... the newest model is more compact than the Kh-31 and will likely be used internally on the PAK FA.

Otherwise both seem to be very capable weapons.

There are rumors that Su-34 tested Kh-31PD ARM, which have a range about 250 km. I think Kh-58USHKE is also somewhere in this range class. Quite a long SEAD hand for Su-34 and PAK FA. I'm sure Su-35 could also use them.

Kh-58UShk is specially made for internal storage on the PAK-FA.

That is good news.. especially the broad band seeker.

With the older models of missile there were dedicated seeker heads, so if your mission was to attack... say a HAWK battery, then you would select the appropriate seeker head and load up for the mission. Those seeker heads would only be good for a limited range of radar emitters, so if a Patriot battery with ESA radars turned on you would have trouble.

These new Kh-31s, like the updated Kh-25s (NATO codename AS-12) and Kh-58s (NATO Codename AS-11) now have broad band seekers so one missile deals with any radars you might come across.

Excellent. This will give great SEAD capabilities to all new Migs and Suhois.

Does Russia have a S-300 based surface-to-air ARM missile - that can be employed against AWACS and such?

I've heard it doesn't :L

flamming_python wrote:Does Russia have a S-300 based surface-to-air ARM missile - that can be employed against AWACS and such?

I've heard it doesn't :L

Unlike IC guided S-300 missiles that where in development but never got operational I think Russians has full Passive guided long range S-300 missile and if all goes terribly wrong with strong electronic counter measures you can always go nuclear.

flamming_python wrote:Does Russia have a S-300 based surface-to-air ARM missile - that can be employed against AWACS and such?

I've heard it doesn't :L

Well i heard there were 5V55VM and 5V55PM Anti radiation variant for S-300PT.

Ive always wondered if the kh-58 and such are superior to the HARM...

KomissarBojanchev wrote:Ive always wondered if the kh-58 and such are superior to the HARM...

I have read that HARM is now modified in a way that if signal is lost HARM goes to the last location it had on GPS guidance. Dont know if something like that has being done with Kh-58 but that does not sound to difficult to do.

Does Russia have a S-300 based surface-to-air ARM missile - that can be employed against AWACS and such?

I've heard it doesn't :L

Using TVM guidance if the target is emitting enough radar energy to track it then I don't see any reason why it couldn't just use that signal to home in on... if it could detect it... of course it is not the most reliable signal to home in on because if the radar turns off on the ground... you can still damage it on the ground if your missile lands nearby, but with an aircraft travelling at 600km/h+ then that isn't going to happen.

Ive always wondered if the kh-58 and such are superior to the HARM...

Different weapons, different performances.

The HARM was fairly ineffectual in that when the target turned off it had nothing to guide it and generally didn't hit anything of importance. It was however relatively cheap and you could pretty much fit it to any fighter bomber fairly easily.

The Kh-58 was more complex and required a pod to use on most aircraft that used it. The pod was used to locate the actual physical location of the target so that if it turned off there was still a good chance of damage. Only a fairly limited array of aircraft could carry the pod and therefore also the missile, but it should have been rather more effective in real use than HARM has been.

Note for the SEAD mission both weapons are fine... in fact Kh-58 is probably overkill... the Suppression of enemy air defences just means you have to get the enemy SAM operators to shut down their radars for certain critical periods of an attack.

Both missiles have been seriously upgraded and likely HARMs performance has improved to the point where both can probably be used for the DEAD, or destruction of enemy air defences mission.

GarryB wrote:

Does Russia have a S-300 based surface-to-air ARM missile - that can be employed against AWACS and such?

I've heard it doesn't :L

Using TVM guidance if the target is emitting enough radar energy to track it then I don't see any reason why it couldn't just use that signal to home in on... if it could detect it... of course it is not the most reliable signal to home in on because if the radar turns off on the ground... you can still damage it on the ground if your missile lands nearby, but with an aircraft travelling at 600km/h+ then that isn't going to happen.

I don't know much about missiles, but if the AWACS turns its Radar off once it realises its being homed in on, the missile could by that stage already be close enough to be able to track just the aircraft itself (if its active radar homing).

S-300 doesn't have such missiles though AFAIK.

I don't know much about missiles, but if the AWACS turns its Radar off once it realises its being homed in on, the missile could by that stage already be close enough to be able to track just the aircraft itself (if its active radar homing).

S-300 doesn't have such missiles though AFAIK.

Few dedicated ARMs or anti radiation missiles also have active radar homing heads.

In other words HARM has a passive radar seeker that is not the same as the active radar homing seeker of an AMRAAM for instance.

This means that when the radar source turns off the missile becomes blind.

There was some talk of a combined ARM (passive radar seeker) and an IR seeker on an air to air variant of the Kh-31, where if the target is an AWACS aircraft if it turned off its radar such a large radar generates enormous amounts of heat during operation so without radar energy to home in on the missile could switch to home in on the heat signature.

Equally an active radar homing missile could be launched at the AWACS aircraft just homing in on the active emissions of the AWACS and if it shut down it could go active and continue the interception.

AFAIK the S-300 has a TVM capability, which means the ground radar acts like an aircrafts radar in a Semi Active Radar Homing intercept like with an R-27ER1 attack where the ground radar paints the target and the missile homes in on the reflected energy. The main difference is that with a SARH missile it is the missile that works out where it is in relation to the target and determines what flight manouvers it has to perform to intercept the target. With TVM or track via missile the missile has a radar receiver and a datalink and transmits the information it detects back to the ground station for processing. The ground based processing will be much more efficient and powerful because it can be as large and as expensive as you need it to be. It wont be destroyed everytime the missile is launched. An advantage of TVM is that the target has little idea of whether it has been engaged or not... it can just detect the lock. There could be ten missiles climbing up to intercept it... or none.

From the tracking perspective the missiles radar wont be huge or particularly impressive, but as it gets closer to the target it should eventually get to be much more effective than any ground based radar... this is good for small targets like cruise missiles. In a net centric environment you could have airborne AWACS aircraft tracking aerial targets flying very low and fast and use TVM with the A-50Us marking the low flying cruise missiles and launch the S-300 missiles high up so the AWACS could transmit command guidance orders via a datalink and engage missiles behind hills or mountains that the SAM site the missiles are launched from never even see the targets their missiles are killing...

GarryB wrote:AFAIK the S-300 has a TVM capability, which means the ground radar acts like an aircrafts radar in a Semi Active Radar Homing intercept like with an R-27ER1 attack where the ground radar paints the target and the missile homes in on the reflected energy. The main difference is that with a SARH missile it is the missile that works out where it is in relation to the target and determines what flight manouvers it has to perform to intercept the target. With TVM or track via missile the missile has a radar receiver and a datalink and transmits the information it detects back to the ground station for processing. The ground based processing will be much more efficient and powerful because it can be as large and as expensive as you need it to be. It wont be destroyed everytime the missile is launched.

Almost. We referred to the S-300P's guidance mode as SAGG, to differentiate it from TVM. TVM is simpler. In SAGG, the missile does work out guidance commands, but they're not acted on like in SARH, they're datalinked to the radar. The radar computes its own guidance commands based on target reflections, then analyzes both sets to determine the optimum course to target, and sends these back up to the missile. In general this means more expensive missiles, but also means more accurate missiles.

GarryB wrote:An advantage of TVM is that the target has little idea of whether it has been engaged or not... it can just detect the lock. There could be ten missiles climbing up to intercept it... or none.

You still need to "lock on" during endgame with TVM or SAGG. Up to that point, the radar generates midcourse guidance commands based on target reflections and sends them to the missile to put it close to the target for TVM or SAGG to function during endgame. The advantage is that you can wait to "lock on" until very late in the engagement process. With a Mach 6+ missile that still pretty much eliminates the concept of reaction time.

You still need to "lock on" during endgame with TVM or SAGG.

A lock on in this case constitutes the seeker in the missile detecting the reflected energy from the target... the missile wont care where that energy originated from... whether it was a ground radar, or an airborne one.

The target will not know what radars are receiving the energy bouncing off its airframe, it will know it is being painted, but it wont know if one missile is coming up to engage it, or ten, or none.

Up to that point, the radar generates midcourse guidance commands based on target reflections and sends them to the missile to put it close to the target for TVM or SAGG to function during endgame. The advantage is that you can wait to "lock on" until very late in the engagement process. With a Mach 6+ missile that still pretty much eliminates the concept of reaction time.

So what you are saying is that a discrete tracking of the target to first detect it and then the occasional pulse to determine it is still going where they estimate it is going is used to direct the missile to a general interception point and then when it is a few seconds away the target will be painted with a radar beam and the intercepting missile or missiles will home in on that reflected signal.

So there is no lock as such that the target could recognise... it would detect the original scan and then ranging pulses, and then after a period it will be painted with a continuous beam for a few seconds till missiles start impacting it.

As opposed to an ARH missile like R-77 where the initial scan and ranging pulses would be detected, and then the radar signal from the R-77 scanning and then locking onto your aircraft and guiding to impact.

The difference is that with SAGG, if there are 2 missiles coming there is only one guidance beam marking your aircraft. If there are two R-77s using ARH then each missile will direct a radar beam at the aircraft as it homes in terminally.

Hey... how about this... fire an R-77 and an R-27EP at the same target with a short interval with the R-77 second.

The R-27EP will arrive first and start passively looking for an active radar emission... and then the R-77 will arrive and scan for and then paint the target with its own radar. I wonder if the R-27EP could then home in on the reflections of the active radar from the R-77?

Certainly it is worth it anyway as the approach of two missiles, one active radar and one not would likely cause the target to scan for threats to work out where those missiles came from... and the act of scanning would attract the R-27EP.

(BTW Thanks for the corrections Sean)

GarryB wrote:The target will not know what radars are receiving the energy bouncing off its airframe, it will know it is being painted, but it wont know if one missile is coming up to engage it, or ten, or none.

"Lock on" is identified based on the frequency, PRF, and latency of the radar signal hitting the target. I'm speaking from the perspective of the guy getting shot at, and what his onboard RWR/RHAW gear is going to tell him, because for the purposes of an engagement that's what is really important.

GarryB wrote:So what you are saying is that a discrete tracking of the target to first detect it and then the occasional pulse to determine it is still going where they estimate it is going is used to direct the missile to a general interception point and then when it is a few seconds away the target will be painted with a radar beam and the intercepting missile or missiles will home in on that reflected signal.

So there is no lock as such that the target could recognise... it would detect the original scan and then ranging pulses, and then after a period it will be painted with a continuous beam for a few seconds till missiles start impacting it.

As opposed to an ARH missile like R-77 where the initial scan and ranging pulses would be detected, and then the radar signal from the R-77 scanning and then locking onto your aircraft and guiding to impact.

Maybe a bit more detail is in order to sort out the EW/EA ramifications of the engagement. The way it works is like this:

ACQUISITION PHASE

1. Target track data is received by the 30N6 (we'll assume an S-300PM). This can come from either a) a 64N6 downlink, b) a 36D6 downlink, c) an EW network downlink, or d) the 30N6 itself acting in its limited search capacity.

2. Battery personnel look at each other, each raising a single eyebrow, the universally recognized signal for "is this guy serious?"

3. Once the target enters engagement range, which is determined by target and/or firing doctrine, target position data gets uploaded to a pair of missiles. This is generated by the 30N6, which begins scanning the sky near the target; this can be especially important if you got track data from a 2D source, as you'll need height (the missing "D") to tell the missile which way to point immediately after launch and accurately guide the missile during midcourse.

4. The pair of 48N6s are cold-launched, ignite, and head towards the target, briefly inertially guided based on the uploaded target data.

INITIAL FLIGHT

5. After stabilization, the 30N6 acquires the missiles and begins tracking, preparing to deliver guidance commands during midcourse. The target is also intermittently tracked. As an aside, radar capability and missile stabilization time are your major drivers for minimum range. Faster systems and better electronics mean you can get this going quicker, giving a smaller minimum range.

MIDCOURSE PHASE

6. While in-flight, the 30N6 periodically monitors the target and missile positions, uplinking course corrections to the missiles to keep them going in the right direction. This is simply command guidance. From an EW perspective, this is basically ops normal for the 30N6, and doesn't indicate a launch. However, if the S-300PM battery belongs to someone who does not employ the 30N6 in search mode, or keeps them offline until required to hide them from ELINT snoopers directing SEAD/DEAD strikes, 30N6 emissions can obviously indicate an active engagement. Plus, if your RWR/RHAW gear says "30N6 is online that way, and it's scanned our airspace at least once", you're going to take what precautions you can regardless.

TERMINAL PHASE

7. Upon reaching the terminal phase, the seeker in the missile activates. The 30N6 begins painting the target continuously using a narrow beam. At this point you know that you've been fired on, the CW signal from the 30N6 amounting to a "lock on". It's not that your RWR/RHAW gear is ignorant of a "lock on", it's that the SAGG system is delaying true "lock on" until the last possible moment to reduce the target's ability to evade.

8. The missile basically has a modified SARH seeker, and a set of guidance systems. The missile receives reflected energy from the target, and generates guidance commands. Except that these are not acted upon, and are instead downlinked to the 30N6.

9. The 30N6, operating in CW mode, generates its own set of guidance commands based on the reflected energy it receives and the position of the missile it is still tracking.

10. The two sets of guidance commands are compared and used to generate a final set, which is uplinked to the missile for action. The missile then makes the course correction required.

11. At endgame, the proximity fuze detonates the warhead. The missile airframe executes a roll prior to detonation to align the directional warhead with the target for maximum effect. At the same time, the second missile (forget about him?) does the same thing.

12. Airplane confetti. Almaz-Antei and Fakel patent the concept of overkill following the second missile detonating.

13. 30N6 scans the area to ensure the target has been eliminated, this is referred to as shoot-shoot-look; fire two weapons, see if you killed the target.

TVM differs in steps 8-10. In a simpler TVM system, target position data from the missile seeker is sent to the radar, which uses it to generate guidance commands, sending these back up to the missile. SAGG is more complicated, but that's a good thing: varying perspectives allow for more efficient flightpaths and better ECCM characteristics. Back to EA/EW, you aren't sure you've been fired at until step 7.

That's probably as detailed as I can get without an unplanned relocation to Kansas. Suffice it to say that when the S-300P series was fully realized with the SAGG S-300PS, it became evident that the USSR for damn sure knew what it was doing when designing a truly modern SAM system (remember that the S-300PT/5V55K was relatively pointless except for familiarization, as it had comparatively short range and relied solely on command guidance). When Gen. Jumper commented that the worst possible move Milosevic could make was to miracle an "SA-10" into downtown Belgrade, he was not being sarcastic or overreacting.

GarryB wrote:Hey... how about this... fire an R-77 and an R-27EP at the same target with a short interval with the R-77 second.

The R-27EP will arrive first and start passively looking for an active radar emission... and then the R-77 will arrive and scan for and then paint the target with its own radar. I wonder if the R-27EP could then home in on the reflections of the active radar from the R-77?

Certainly it is worth it anyway as the approach of two missiles, one active radar and one not would likely cause the target to scan for threats to work out where those missiles came from... and the act of scanning would attract the R-27EP.

Won't work. A reflected signal is not the same thing as an emitted signal. Otherwise your R-27EP is technically acting as a SARH weapon, not a passive homer. Seeker design and functionality for the two guidance modes are very different. A passive seeker is looking for the source of the emitted energy. It might sound similar but in practice and design they are very different concepts.

Now, whether or not you could calibrate an R-27ER seeker to home on reflections from an R-77 seeker head...that's another story entirely. It that case I imagine it'd depend on the strength of the emitted signal from the R-77, and the magnitude of the reflected signal able to reach the R-27ER.

Thanks Sean.

So basically the main advantages of SAGG would be it combines the advantages of enormous ground radars, with having a radar in the nose that might start off a long way from the target but as it gets closer its quality of data increases rapidly, plus of course the processing power that a ground network can provide.

The talk of AWACS aircraft controlling AAMs and SAMs for the terminal part of their flight could make it quite interesting for countries with lots of mountains like Iran...

Regarding you comments aboutR-27EP, you are quite right, but I seem to remember a Russian nose mounted sseker array that included both ARH with a range of 50-60km and a passive radar seeker for ARM use that could lock on to signals up to 200km distant. From memory it was a large array... and I think it might have been aimed at the Kh-31/Kh-58 sized missiles.

It would certainly be interesting for use against shipping where an emitting ship could be launched upon and if it shuts down it could revert to active radar homing. (note I think the 50-60kmlock on range was for ship sized targets... not aircraft).

Such a seeker would be interesting for an RVV-BD type missile or perhaps even a new Kh-31PD with a flight range of 250km... perhaps more if all high flight profile.

TVM basically combines command and SARH. SAGG takes TVM and gives it a bit more accuracy and ECCM capability at the cost of making it a bit more complicated and therefore expensive. The best way to explain TVM is that it's command guidance, but the receiver array is in the nose of the missile for better perspective. Remember that TVM predates SAGG by a bit, as the Patriot SAM-X program began in the 60s, so it's not suprising at all that the USSR made some logical evolutionary improvements.

An AEW&C platform could be used to control a SAM or AAM at endgame, sure, but it'd need a phased array radar capable of putting out a powerful, narrow beam for target illumination (assuming TVM, SAGG, or SARH...or even GAS/GAI, which is another guidance method altogether). Plus, the missile would need to be compatible with the illumination signal as well as the ground-based radars. Not an issue, but likely only really workable for large, long-range weapons.

A large seeker for both ARH and PRH is certainly doable, you could use a phased array and share it out for the different tasks, or even use the array for ARH and flush side or fin-mounted receivers for PRH, or if you've got enough diameter use separate arrays for either role.

Here's a proposed active (MMW)-passive radar seeker: http://www.google.com/patents/US6806823 There's also an AGAT active/passive seeker here: https://www.russiadefence.net/t1621p45-meteor-versus-rvv-bd-long-range-a2a-missile#13752

GarryB wrote:Thanks Sean.

So basically the main advantages of SAGG would be it combines the advantages of enormous ground radars, with having a radar in the nose that might start off a long way from the target but as it gets closer its quality of data increases rapidly, plus of course the processing power that a ground network can provide.

Are you implying that 48N6 can guide itself in terminal phase in case link with radar is broken for some reason?

48N6 has some kind of seeker



Described by Almaz-Antej as semi-active radar.

The missiles have a seeker, it is just that they are not ARH seekers like an R-77, they are passive radar seekers like R-27ER missiles.

Basically the huge powerful ground based radar antenna of the S-300 are used to paint or mark the target aircraft in the last part of the interception. The radar antenna in the nose of the missile doesn't transmit anything, it just tries to capture a signal from the ground radar directed at the target and reflecting off the target in all directions.

It is a bit like a laser guided bomb... the laser guided bomb doesn't have a laser on it, just an optical device that can detect laser light. If you shine a laser beam from a laser target marker onto a target that a LGB is falling towards and it is calibrated to the bomb, then when the bomb detects the laser energy reflecting from the target it will activate its control surfaces and manouver to try to fly towards the laser reflections.

It is the same with the S-300 missiles, except instead of laser light it is radar beams.

Are you implying that 48N6 can guide itself in terminal phase in case link with radar is broken for some reason?

What the missile needs for the interception are two things... a radar beam illuminating the target, and a datalink passing it accurate course information to tell it where to fly.

From what Sean has said it could calculate its own manouvers if needed, so it is possible that a future AWACS platform like A-100 might be able to take over control of an intercept, presumably by illuminating the target and providing a datalink connection to complete the interception.

Of course as Sean points out it is only in the terminal phase where the target is illuminated so it is perfectly possible... I guess that the AWACs aircraft could handle the target painting role...

Why I hear you ask.

Even with specialist radars on poles the performance of radars on the ground is effected by the curve of the earth and of course those bumps we call hills and mountains.

With an AWACS or indeed even an airship flying at 30,000m those hills and mountains are no longer blocking any direct line of sight signal like a radar beam.

A SAM battery could be located in a deep valley concealed by the very mountains that would normally make such a system placement stupid... why place a 150km range SAM somewhere where the mountains around it block the view of any enemy aircraft more than 10km from it except those at 20,000m or higher.

With its sensors turned off, or simply listening for emissions with a large airship operating above at 30,000m able to see every nook and cranny for 800km in every direction and able to guide dozens or hundreds of missiles at a time... could that be the future of air defence?

Every other valley could contain S-300, S-400, and S-500 missile batteries, their radar vehicles on top of mountains listening quietly.

And of course a nearby airbase with PAK FA and Su-35s to protect and when needed attack enemy air threats.

Of course I am very interested to see the Kuznetsovs upgrades. If it gets nuclear propulsion... which is most likely, and EM cats (which is also quite probable) I wonder what sort of AEW aircraft they will use. A Hawkeye type aircraft would be very useful... with a fixed wing aircraft and plenty of fuel I would hope they could put some serious processing power on board and come up with a very capable aircraft that could perhaps becomes an export success. I am sure lots of countries with a lot of empty space would find such an aircraft to be a very useful gap filler. Russia, Iran, India, Canada, Indonesia. Even New Zealand could use something that could fly out and locate missing yachts, or vessels in distress.

I don't think an S-300P round can guide itself. It uses what is basically a SARH-type receiver antenna, so if it isn't getting radar returns it can't find the target unless it has a HOJ capacity, and the target is jamming. What it might be able to do is continue onward using the guidance commands it generates if the uplink is broken but the 30N6 is still painting the target. This seems a bit redundant though, as the missile is command-guided using midcourse updates during the majority of its flight. If the uplink goes down there, the missile has nothing to do.

Also, AWACS midcourse updating is one thing, but not really that big of a deal. The game-changer will be if they incorporate a midcourse update capacity allowing signals to be received from the Nebo-M radar. You could either do it directly, or have the signals transmitted from Nebo-M to the 91N6 or 92N6 for processing and uplink. That will give you a legitimate counter-VLO engagement capacity to hang your hat on.

As for the future of air defense...if I was going to try and speculate, I'd think that we'll see two things. 1) Space-based EW assets. Survivable, and you'd be able to paint something like a B-2 easily, removing the one platform that will give the Nebo-M true fits. 2) Non RF-based detectors. I can see LADAR or advanced optics being employed, the latter especially eliminating any sort of advantage an LO platform possesses. Getting any of these to work at the level required to take over from traditional RF-based sensors is obviously a long way off, however.