Is Russia safe from F-22 and Β-2?

Those articles sounds ridiculous. I can't see how those are the news at all because the common sense says you should look or ask both sides if you want to get the truth out.
I am wonder for those guys flying around in invisible F22, how do they know they are invisible for Russians in Syria? Just can't take for granted statement one of the pilot who just says - They can't see me at all and I have an God's eye over them! Maybe they don't want you to know you are tracked or seen on the screen of some flying or ground system Russian use for air space observation over Syria?

So I briefly read over the articles and I'm confused.

So how does the pilot know he wasn't being tracked? Actually, he didn't say he was never tracked at all. But I'm more curious as to what engagements were had because apparently there were none. But load already said, he doesn't know if he was or wasn't. Second of all, L band radar would pick him up and most passive sensors would have trouble picking up location of said radar. Hence why anti radiation missiles do not work well against a L band radar.

For all we know the Russians were tracking it and stayed silent. They have done this multiple of times already in Syria unless the US did something real stupid then they would say something.

And if they were using the raptors in Syrian airspace in full stealth, then that gives Russians a lot to learn from, same was from tomahawk launch.

The other issue I thought of as well is when the F-22 would turn on its radar, it will light up to most radars due to the radiation. So unless the F-22 flies around with nothing but passive sensors, then it really isn't fully stealth

miketheterrible wrote:So I briefly read over the articles and I'm confused.

So how does the pilot know he wasn't being tracked? Actually, he didn't say he was never tracked at all. But I'm more curious as to what engagements were had because apparently there were none. But load already said, he doesn't know if he was or wasn't. Second of all, L band radar would pick him up and most passive sensors would have trouble picking up location of said radar. Hence why anti radiation missiles do not work well against a L band radar.

For all we know the Russians were tracking it and stayed silent. They have done this multiple of times already in Syria unless the US did something real stupid then they would say something.

And if they were using the raptors in Syrian airspace in full stealth, then that gives Russians a lot to learn from, same was from tomahawk launch.

The other issue I thought of as well is when the F-22 would turn on its radar, it will light up to most radars due to the radiation. So unless the F-22 flies around with nothing but passive sensors, then it really isn't fully stealth

The best proof of the usability of air defence systems against the f22/f35 is the procurement of S400 systems.


If the f22 is not possible to shoot down then make more sense to buy long wave radars and interceptor jets.

The S400 units are not cheap, each of them cost as much as five-ten interceptor jet.

Is Nebo-M in Syria? Curiously enough. Cause that will detect that F-22 at long ranges.

Regarding this topic I would like to know what you think about the potential use of a bi-static benefit of SARH guided missiles against stealth. I posted this a while back on keypub but the reactions were not of much use:

There is a seemingly unusual notion which the Russians have with their SAMs and AAMs which results in the use of SARH/SAGG missiles, although ARH seekers are available.

I will concentrate on SAMs here because the developments there make the case more clear.
Russians have developed various active radar seekers for their SAMs, especially the BUK series and their very long range S-300 with 200km+ range missiles would be candidates for ARH seekers.
However, they stick to SARH seekers even for their new century designs, the S-400 and BUK-M2/-M3, where others like the French, Japanese went for ARH seekers (Aster, etc). One exception would be the naval S-400 variant with ARH being developed but here the anti-cruise missile over-horizon effect should be the reason.

Either their ARH perform bad, or the illumination power of their engagement radars offer still more RF energy on target or there are other benefits for a SARH seekers.


Stealth designs rely on deflection rather than absorption as the key physical effect for their VLO performance. Systems like the e.g S-300/-400 work in a bi-static mode with their SAGG/TVM guidance, means that the RF signal receiver is at a different position and at a different angle than the attacking illumination radar. The deflected RF energy may would not reach the emitting radar, but a bi-static SARH receiving seeker in the SAM that can attack from angle below the VLO target or above it and perform angle search pattern would have better chances to catch deflected RF energy, enabling a lock on the stealth target. This method would decrease the biggest problem with missile radar seekers, namely that they have to work in X-band, for which stealth designs are optimized and no effects like aircraft feature size can be used for improved performance (VHF-band).

One key element for this method to work, is a blind illumination capability of a portion of airspace (without actual track) based on coordinates from a radar system that actually detects the target. There is much debate about this; Russians say that VHF band radars can see smaller stealth designs such as the F-35 like any other radar. Some pro US stealth friends might say the F-35 has the same pea size in VHF-band as in X-band. We can take something in between, but a highly advanced IADS like the Russian one has assets such as the "Container" OTH system for early warning and coarse location, as well es high power static line of sight systems with very large apertures such as the Voronezh and Resonaz systems, with systems like the mobile Nebo-M acting at lower tiers. There is more, such as passive means, EO, IR, multi-static "trap" radars networks.
There must be rough target coordinated available for such a bi-static SARH engagement, with a accuracy as provided by multi-band systems such as the Nebo-M or single VHF-band Nebo-SVU, otherwise the RF energy of the illumination radar wont be sufficiently accurately concentrated on target (airspace portion).
The S-300/400 SAMs have robust missile up- and down-links, hence they would work with course updates via VHF-band target coordinates until terminal phase where the SARH seeker would try to catch illumination RF energy deflected to different directions by the stealth design.
The addition of satellite positioning systems to the engagement radars of S-300PMU2 and S-400 could be a hint for the use of this method.

Hence I have the feeling that this described bi-static method directly benefits from the main function of stealth designs, RF-energy deflection, and could be the main reason why even the S-400 is still old fashioned SARH and possibly why the R-27 soldiers on.

Counter measures like a change of aspect or direction of the VLO asset would not change to overall situation. First there is the question whether it would be worth the risk to change direction after the attack has been detected by sensors and the most optimized face (front) has been directed to the threat emitter.
Even a all aspect VLO asset would still be optimized to deflect waves away from the bore sight of the threat radar. If we assume that the biggest portion of the radar waves are deflected in a bore sight range of 15° to 90° in all directions, a limited degree portion can be determined from the bore sight of the threat radar where the SARH seeker has to search for deflected RF energy. However I'm no expect on RF wave behavior hence this deflection angle band could differ.
More so; if the VLO asset changes aspect relative to the bore sight of the threat illumination radar to change the direction of deflected radar waves, to decrease chances for the bi-static SARH seeker to pick up RF energy, this would force it to expose a less optimized face to the bore sight of the threat radar. So if the SARH seekers lock on the target is broken, the redundant SAGG/TVM system could switch back to command guidance mode as it now has got a own track of the VLO asset.
You may be thinking about a sudden maneuver that would suddenly break the lock of the SARH seeker. But any change would just reduce the amount of deflected RF energy e.g if the VLO asset exposes its least optimized face to the threat emitter, so that more RF energy is sent back to the radar and hence less is deflected to the bis-static positioned SARH seeker.
Advanced SARH missiles with missile up- and down-links + advanced autopilots only make use of the SARH seeker in terminal phase, not like the HAWK or S-200 which had to catch the RF energy at great distances while on the launcher. Hence they need much less of reflected or deflected RF energy. The deflection angles of VLO assets are confined and there should be enough RF energy deflected to that angle band to allow for terminal phase SARH guidance.

Back at Keypub, there was the arument about the penalty on kinematics a bi-static position maneuver would require.


Finally here is a graphics of the effect described in a very adverse form in favour for the stealth assets:

It doesn't matter really.

The SAM X band radars doesn't have to "see" the target aircraft, the missile seeker has to see it on the last few kms.

If there are multiple X band targeting radar around the aircraft then all of them can illuminate the target, so there is quite high chance to have reflection from at least one radar.

Traditionally, there is the opportunity to scatter passive illuminator controlled by the NEBO-M.


I think if sameone can found a deployment map of a full S-400 battalion then it can give clue how they want to use them.

Actually, as I think about it the lack of passive X band illuminators controlled by the S band radar ( like on the aegis ships) showing that the Russian military is quite confident it can hit the stealth planes with the current configuration .

Either their ARH perform bad, or the illumination power of their engagement radars offer still more RF energy on target or there are other benefits for a SARH seekers.

Assuming you're talking about S-400, the GRAVESTONE engagement radar offers higher energy and ECCM potential than what you can put on the missile. SARH is also cheaper than ARH but considering latest Russian AESA development, they're slowly getting there; some S-350 missiles use ARH now.

In regards of bistatic SARH, I agree with Singular_Transform. S-400 will never act alone but a part in greater IADS. We can look at what's known on S-400 air defense regiment where they have three batteries and each battery have a GRAVESTONE radar to direct the TELs after getting initial data from BIG BIRD. So within S-400 itself, you have three (three, not one!) engagement radars that can look at the same target. One can emit while other two listen. It won't be a bistatic situation but a multi aspect one.

The super VLO F-35 (or so they claim) can fool one GRAVESTONE but it won't be fooling the other two hidden and listening engagement radars. There is also BIG BIRD whereby by collaborating BIG BIRD track with GRAVESTONE, you can know you're dealing with a stealth bird as BIG BIRD gives high reading but the latter give low reading.

This also didn't account for other assets that will support the S-400 like forward deployed Pantsir-S2, Tor-M2, Sturna bistatic early warning radar, Vega passive ELINT, A-50U AWACS and Nebo series complexes to provide additional sources of radar energy and observation from other directions that are not within the mythical low RCS, low aspect angle zone of the threat aircraft. Western experts only considered phantasmal one-on-one VLO engagement but the ugly truth is that, there won't be one GRAVESTONE or radar watching.

By the way, it is technically impossible to have the same tiny X-band RCS in VHF as EM absorption quickly changes with lower frequency. I am pretty sure you are aware on why, thus reasoning posited by american stealth 'expert' is dead wrong.

I also read your post on keypub on your idea PeeD; it astounded me that they're mostly talking about one-to-one interception. Russian high level SAMs don't work one-to-one. They are straight up multi aspect, even within single operational SAM regiment. You can see the trend even with Buk-M 1 to 3 where every TEL have their own radars.

That means they're prepared to deal on not only when their main engagement radar was taken out but also high confidence detection as you can learn more of the target when you see it from different directions. Granted this arrangement is very expensive when it's scaled up to S-400 level but even then they don't simply have one engagement radar but multiple. They are further supported by other radioelectronic units.

We have to talk and think about X-band SARH guidance performance of "stealth" assets. We have two driving parameters on electromagnetic waves that can be perfected to various degrees, airframe deflection shaping and RAM/RAS absorption. Naturally we assume the worst case because X-band stealth is easier feasible and SARH systems are mostly operate in that band. So the suggested operation regime is not suggesting that it is even necessary against current threats F-35/-22/B-2 but for a scenario where X-band stealth performance is so high that illumination becomes ineffective.

Singular_Transform, your passive illumination concept you say to be in use with the Aegis system would be the method I suggest to enable SARH illumination of a invisible target. I further suggest to additionally exploit the bi static seeker position to make use of deflected RF energy (caused by stealth shaping).
I also think that such a operation mode could be already implemented in S-300PM/S-400 as there is no real hardware change necessary.
I can even go further and ask if a, as you call it "passive illuminator" with no active receive function could work at a higher transmission power level.

Singular_Transform and Enera, your concept of multiple CW illumination would proportionally increase the RF energy on the target. It is a valid point of course, more so because the illuminator is a electrical steered array that can almost instantly switch between targets. Such a operation mode should be built into the overall system. The multi-directional illumination should of course vastly improve the system performance.

In total we have all this potential effects of SARH missiles which a ARH concept would lack. The most important effect could be the bi-static seeker position effect for deflected RF energy, but I seem to be the only one talking about this potential effect. Carlo Kopp of APA just went so for as to suggest command guidance based on Nebo-SVU position information.
In my view this operation would be the lowest tier back-up mode --> "blind"/passive illumination the main method --> off-set bi-static seeker positioning to catch deflected RF energy the "stealth-relativising" effect (feasibility questioned) --> multiple, multiposition illumination the brute force final backup for successful engagement.

I'm not a friend of command guidance, it should be only a back-up in modern systems.
I suggest a hidden Soviet/Russian wisdom, not technology for the use of SARH systems. The S-350 could be ARH because it is lower tier than S-400 and has a mission such as the interception of cruise missiles in an over horizon mode, same as naval S-400.

Isos wrote:http://theboresight.blogspot.fr/2016/07/the-end-of-primacy-russian-federation.html

Rumors of a Russian Su-30 Sm detecting F-22 at more than 40km in Syria.

Interesting link but it stopped a year ago.

One S-400 regiment has three - four X band radar, one S (2HGz and bigger than AEGISSPY-1) radar .

Means the three X band radar will give to the rocket passive seeker illumination from three different point.


The S band radar OR a NEBO-M radar can direct the illuminators to the target.
The X band radars can be used as pencil beam illuminators, working 100% duty cycle.


The missile seeker head is closer to the target say ten times than the radars, means the stealth is quite useless even for passive mode rockets.

most are worried that command guided are easy to jam simply because the command module can be jammed. Which could render the whole complex useless because 1 system is effectively jammed or destroyed.

Russians use command radio guidance in systems which are short range. They are generally expected to be much less subject to jamming efforts as their normal enemies are cruise missiles and PGMs without EW capability. EW assets of the adversary will concentrate on the longer range systems threatening the carrier aircraft.

None the less command guidance was last used in the earlier S-300P variants and we should expect a Russian wisdom behind this. Command guidance was surely deemed as too fragile. In Iran for example, export Tor-M1 were soon upgraded with a separate indigenous command guidance antenna/channel because the system was already compromised via the Greeks. However Iran is likely to be forces to use the Tor-M1 against carrier aircraft because the state of it's IADS, Russia on the other hand has a IADS where the Tor-M1 could easily never face a carrier aircraft, just CM/PGM.

In my last point I counted the benefits of SARH/SAGG guidance plus a potential effect I think that exists. Neither ARH nor radio command guidance have those benefits for robustness.

Singular_Transform described the brute force method in which 3 radars illuminate the stealth target and hope for a lock-on of the SARH seeker once radio command guidance (feed by Nebo-M position data) has got it close enough to the target. At one point there must be a burn trough. In general the S-400 should be simply to strong to even successfully jam its radio up-link channel to disrupt radio guidance with current EW systems. SARH/SAGG potentially also have higher discrimination capability and it simply gets better and better the more it closes to the target.
The command link remains a potential weak spot, possible that the S-400 is by pure power strong enough to neglect that against current EW systems, but there must be a good reason why smaller/shorter ranged systems like the Buk family avoid it. If there is a bi-static effect against stealth as I described, the benefits of SARH/SAGG are even clearer.

PeeD wrote:Russians use command radio guidance in systems which are short range. They are generally expected to be much less subject to jamming efforts as their normal enemies are cruise missiles and PGMs without EW capability. EW assets of the adversary will concentrate on the longer range systems threatening the carrier aircraft.

None the less command guidance was last used in the earlier S-300P variants and we should expect a Russian wisdom behind this. Command guidance was surely deemed as too fragile. In Iran for example, export Tor-M1 were soon upgraded with a separate indigenous command guidance antenna/channel because the system was already compromised via the Greeks. However Iran is likely to be forces to use the Tor-M1 against carrier aircraft because the state of it's IADS, Russia on the other hand has a IADS where the Tor-M1 could easily never face a carrier aircraft, just CM/PGM.

In my last point I counted the benefits of SARH/SAGG guidance plus a potential effect I think that exists. Neither ARH nor radio command guidance have those benefits for robustness.

Singular_Transform described the brute force method in which 3 radars illuminate the stealth target and hope for a lock-on of the SARH seeker once radio command guidance (feed by Nebo-M position data) has got it close enough to the target. At one point there must be a burn trough. In general the S-400 should be simply to strong to even successfully jam its radio up-link channel to disrupt radio guidance with current EW systems. SARH/SAGG potentially also have higher discrimination capability and it simply gets better and better the more it closes to the target.
The command link remains a potential weak spot, possible that the S-400 is by pure power strong enough to neglect that against current EW systems, but there must be a good reason why smaller/shorter ranged systems like the Buk family avoid it. If there is a bi-static effect against stealth as I described, the benefits of SARH/SAGG are even clearer.

I forgot to mention this;PeeD, you need to make an introduction thread in the https://www.russiadefence.net/f6-member-introductions-and-rules as it's a forum rule.

I remember reading through RDF about command guidance. Command guidance is not easy to jam as you think since:-

1) The command is done through a narrow beam link which makes signal intercept difficult.
2) The missile would basically have its communication antenna to only look backward, to the command link device and ignore others coming from front. To disrupt this you need to be physically located between the missile and command device. By the time you're there (which is quite impossible if the missile is already on top of you), there are also short ranged defenses that can shoot you down.

I'm not sure why you heavily advocate bistatic SARH, PeeD. It's basically a downgraded SAGG or TVM and Russians have something better, which is SAGG and GAS/GAI. The missile would come from the top so any 'stealth' the F-35 in your picture have would be less useful as the radar beam would be diffracted upward which the SAM can pick up. Then the missile can tell the X-band radar that the readings from early warning radar is correct where there is a stealth plane. The X-band radar can then give command to the missile to get as close as it can, depending if it's TVM or SAGG, relying on updates from the missile to roughly gauge the target's position.

Depending on the guidance mode, the engagement radar don't even need to continuously illuminate the target for endgame but just a few pings to determine where is the target and set the optimum intercept solution. At the end of engagement, the X-band radar can do another brief signal but stronger so the missile knows precisely when and where to explode. As far as I know, S-300V operated that way where the intense CW is only done at endgame. No need to emit all the time since that will draw attention of HARMs.

Again I stress that you need to see this as a multi-aspect situation; Russian SAMs never operate alone but a part of network. One radar can emit and others listen. The command vehicle can get extra info from the listeners and then help the emitting radar to adapt to the target. Assuming it as one-to-one engagement which I perceived from your bistatic SARH idea isn't correct at all. They're more complex than you think.

ARH have its uses as you said, to intercept inbound cruise missiles. It can do fine for the job, the West don't have cruise missile as sophisticated as ancient P-700/1000 any time soon. For general work, ARH would be logically combined with command guidance.....which makes it a better version of SAGG since now the missile can know the target better as it can use LPI waveforms to burn through target's self protection jammers.

Please don't discount ARH concept in general either since Russians already have AESA through Agat (http://www.ausairpower.net/APA-Legacy-SAM-Upgrades.html#mozTocId705713) . While expensive than SARH, they can deal with advanced threats like Growler or an AWACS protected by DRFM jammers. If you want to know further on Russian SAM guidance methods, you can refer to http://stealthflanker.deviantart.com/journal/SAGG-TVM-and-GAI-Today-s-Modern-SAM-Guidance-335340027 . Majority of Soviet/Russian SAMs have datalink so even if the missile terminal guidance is broken for some reason, they can still fall back to command guidance through datalink if within LOS. At the time of S-300P creation, it have command guidance because it was the cheapest to apply. Appearance of Growlers and decoys in Iraqi wars provided impetus to further develop the system to include TVM and then SAGG; technology improvement didn't happen overnight.

@Enera

I neither do think that radio command guidance is easy to jam nor is my view on TVM/SAGG simplistic. The question is whether SAGG or radio command guidance is more robust. The former is more redundant and in total more robust (also more than ARH imo)

My bi-static effect is perfectly in line with SAGG+GAI, it's just a effect which occurs against stealth targets that I predict.
I have some doubts on the amount of RF energy scattered to the upper hemisphere due to stealth designs. They are basically divided in the horizontal plane (well visible by the radome). Hence it is possible that a great amount of RF energy is scattered downwards below the aircraft (but away from the emitter), leaving less for the top attacking SARH seeker. However this is a general problem, a bi-static engagement would work in top attack and in a below-attack maneuver.

GAI and illumination just in the last seconds is a given, any modern system with SARH method must have it otherwise no energy optimized trajectory can be flown etc.

To make it clear: this is a adverse condition analysis with a stealth target with the best physically possible shaping and RAM. I never claimed the use of a bi-static effect is necessary for the F-35/-22/B-2. The same adverse condition approach let me ignore the rest of the IADS network, just the S-300PM-S-400 battery and a Nebo-M should be sufficient for the scenario.

SAGG was no response to Prowlers over Iraq'91. I highly doubt special waveforms of a small ARH seeker is in any form superior in an EW environment than a high power, potentially multiple position illumination, and SAGG system to ranges of up to 300km.

PS: You linked a article by stealthflanker, if yourself are stealthflanker I have a interesting information for you. Let me know.

PeeD wrote:@Enera

I neither do think that radio command guidance is easy to jam nor is my view on TVM/SAGG simplistic. The question is whether SAGG or radio command guidance is more robust. The former is more redundant and in total more robust (also more than ARH imo)

Well of course SAGG will be more robust but you need to see this in cost effective terms like GarryB explained; there are tools for specific situations. I already put my conjecture that command guidance was initially used in S-300P because it's the cheapest to do. At that time I doubt USSR have enough money and it was the shortest way to get the complex to service.

PeeD wrote:My bi-static effect is perfectly in line with SAGG+GAI, it's just a effect which occurs against stealth targets that I predict.

Okay. So I'm not sure what's to be discussed because it looked like you were trying to push a new concept? SARH missiles would home into scattered RF energy from the engagement radar's beam regardless so it's non-sequitur.

PeeD wrote:I have some doubts on the amount of RF energy scattered to the upper hemisphere due to stealth designs. They are basically divided in the horizontal plane (well visible by the radome). Hence it is possible that a great amount of RF energy is scattered downwards below the aircraft (but away from the emitter), leaving less for the top attacking SARH seeker. However this is a general problem, a bi-static engagement would work in top attack and in a below-attack maneuver.

It doesn't matter for Soviet/Russian SAMs as they're linked to each other and have lots of supporting listeners. Even if the engagement radar and/or the missile can't catch enough RF energy deflected by the target, other linked equipment can help advice them both on where the target is.

PeeD wrote:GAI and illumination just in the last seconds is a given, any modern system with SARH method must have it otherwise no energy optimized trajectory can be flown etc.

No comment.

PeeD wrote:To make it clear: this is a adverse condition analysis with a stealth target with the best physically possible shaping and RAM. I never claimed the use of a bi-static effect is necessary for the F-35/-22/B-2. The same adverse condition approach let me ignore the rest of the IADS network, just the S-300PM-S-400 battery and a Nebo-M should be sufficient for the scenario.

No, you can't ignore the rest of the IADS. The SAM complexes are specifically built to work together in a big ecosystem. You can make it singular case all you want but the way Russian SAMs work is that they become world's best by integration and networking with other systems at deep level. Remove that and you will have something resembling a slightly better Western SAM system. It would be by far, a decade more advanced than any Western system however.

PeeD wrote:SAGG was no response to Prowlers over Iraq'91. I highly doubt special waveforms of a small ARH seeker is in any form superior in an EW environment than a high power, potentially multiple position illumination, and SAGG system to ranges of up to 300km.

Different situation calls for different tools. SAGG can work with ARH too because SAGG is just that the missile and engagement radar work out an intercept solution. The missile can gain information from either the RF energy of the radar scattered by the target (SARH) or the missile actively detect the target (ARH) before committing to SAGG. Of course ARH would be the future because the missile is closer to the target than the engagement radar.

The target then need to deal with two kinds of RF source; the engagement radar and the missile seeker. If it tries to jam either one, the ADMS can triangulate where is exactly the target. If it wanted to jam both, it will be forced to distribute jamming power between the two, enabling both the radar and missile figure out they're being jammed because the jamming signal will be weaker.

PeeD wrote:PS: You linked a article by stealthflanker, if yourself are stealthflanker I have a interesting information for you. Let me know.

No, I'm not stealthflanker. stealthflanker is a member of RDF.

@Enera

So I'm not sure what's to be discussed because it looked like you were trying to push a new concept? SARH missiles would home into scattered RF energy from the engagement radar's beam regardless so it's non-sequitur.

It's not a new concept. It is a effect that I have not seen anyone mentioning. The trajectory can be optimized to exploit that effect.

It doesn't matter for Soviet/Russian SAMs as they're linked to each other and have lots of supporting listeners. Even if the engagement radar and/or the missile can't catch enough RF energy deflected by the target, other linked equipment can help advice them both on where the target is.

We talk here about a SAGG/SARH engagement, just knowing position would force the system to work in radio command guidance mode (which accuracy at 200km+ could be questioned). If a stealth design scatters 90% of illumination RF energy below the aircraft, a top attack trajectory could be inefficient. A "dive --> climb" engagement trajectory would be a solution to that problem if kinematic reserves are sufficient. In such a operation regime the bi-static seeker angle could be optimized to go for stealth design scattered RF-energy

No, you can't ignore the rest of the IADS. The SAM complexes are specifically built to work together in a big ecosystem. You can make it singular case all you want but the way Russian SAMs work is that they become world's best by integration and networking with other systems at deep level. Remove that and you will have something resembling a slightly better Western SAM system. It would be by far, a decade more advanced than any Western system however.

Sure it is integrated. Point is, if my prediction of the bi-static effect is true, shaping stealth can be countered by a S-300PM+Nebo-M only, without any hardware change (potentially already there). So for a analysis of the case all other systems can be excluded.

Different situation calls for different tools. SAGG can work with ARH too because SAGG is just that the missile and engagement radar work out an intercept solution. The missile can gain information from either the RF energy of the radar scattered by the target (SARH) or the missile actively detect the target (ARH) before committing to SAGG. Of course ARH would be the future because the missile is closer to the target than the engagement radar.

The target then need to deal with two kinds of RF source; the engagement radar and the missile seeker. If it tries to jam either one, the ADMS can triangulate where is exactly the target. If it wanted to jam both, it will be forced to distribute jamming power between the two, enabling both the radar and missile figure out they're being jammed because the jamming signal will be weaker.

There is a certain envelope where SARH/SAGG will always be superior to ARH and a limit at which ARH becomes stronger than SARH illumination.
So no, ARH would not be the future. With a aperture size and power output of a S-300PM it is well possible that at up to 200km it is literally always stronger than ARH in terms of on-target RF energy. It's RF source is also 200km away which makes jamming harder.

ARH RF-energy is always limited to SAM diameter/battery power and even with a GaN AESA aperture its power will only be superior to a S-300PM class system at a long range. So it's about envelopes and yes at some range, ARH becomes certainly better than SAGG/SARH.

The future could be a hybrid ARH seeker that works with own illumination at very long ranges or over horizon engagements and goes for SARH in cases of jamming and stealth targets. Against stealth targets the multi radar illumination could proportionally increase RF-energy for the SARH seeker and/or the proposed bi-static effect neglect shaping stealth.

About the topic. The stealth asset I have the biggest respect of is the B-2.

Reason is that I find it convincing that its bottom surface area is smooth almost monolithic with feature sizes large than metric VHF-band wavelenght. All its features like cockpit, intakes and exhaust are on the upper half.

If we exclude assets like space based sensors, OTH radars, AEW aircraft and high performance long range high altitude interceptors like the Mig-31 and only consider ground based assets, we might have troubles with it. Such a scenario is not unlikely in a nuclear war where static assets like airfields and OTH radars are not operational anymore.

Mindstorm posted very useful professional analysis of stealth asset RCS estimation. But in the mentioned scenario a horizontal RCS would not be representative. At operationally relevant angles of ground based radars, the upper, half of the B-2 with the smaller feature sizes could be completely blocked.

There are still plenty other sensors left such as IIR with emerging performance levels, "radar traps" such as the Barrier series and the complete passive and ESM/ELINT world.

However it's the large B-2 which could neglect the benefits of VHF-band systems. A Nebo-M could have just small range penalty against F-22/-35 and -117 stealth, mainly due to the VFH asset of the system but a much larger penalty against the B-2.

A possible counter-VHF effect due to size/feature size for the B-2 would also explain why the Americans went for the B-21.

I'm aware that OTH radars can detect B-2 size shaping stealth, at least HF wavelength has no potential feature size effect in the same way VHF has no problems with smaller feature sizes of F-22/-35/-117.

However the problem with OTH radars is that they are static. A massive saturation attack by Tomahawks up to nuclear ballistic missile attacks could take these vital systems off. This is the nature of any static, large system, it's survivability is limited and in a serious conflict you just try to keep it alive as long as possible. We all know how potent the Russian IADS is, but here the determination of the opponent counts, if it is ready to spend 300-600-1000 Tomahawks for a single vital object, there isn't much that can be done. Furthermore there are limitations in scan rate and 360° coverage with OTH radars.

IR spectrum is another way but with the assumed cooling and sub-sonic speed, the ranges should be limited to 100km for cost effective TI sensors.

Maybe I overestimate the feature-size wavelength problem of the B-2 and e.g the gaps between the control surfaced are sufficient for VHF-band scattering. But maybe it has a stealth operation regime that makes it effective against VHF-band and hence the decision for the B-21.