How effective are modern radar systems at detecting low-RCS targets?

[Burke095]

the issue is not about an AWACs focusing "all available tracking energy" onto a single target, and considering the processing and sensor power on an E2D, that would be a spectacular and ignorant misuse of a system

"Why is this a major advance? It turns out that continuous scanning across the full 360 degrees limits power applied in any one direction. To keep the scan revisit rate relevant, the radar can only spend a brief instant on each degree of arc before sweeping around again. That is usually more than enough to pick up a target and establish its track. But what if the target is especially hard to see – i.e., stealthy? Or what if it is flying low in ground clutter? In that case, what’s needed is a focused beam that dwells longer, sending more energy in a specific direction. Increased energy transmitted out produces more energy received back and a sharper radar return.

The E-2D for the first time combines both modes in a naval platform. Electronic scanning enables the radar to function both as a rotating beam generating 360-degree coverage, and as a staring beam that can pour radar energy into tracking even the smallest, stealthiest targets. As a result, the E-2D radar is so flexible that its crew can rapidly switch between three main modes of operation. First is the classic rotating beam, ensuring the strike group has no blind spot. Second is a mode which continues the rotation but carves out a 45-degree slice, for example, where power is enhanced. The crew can focus the beam at the direction of a known or cued threat and boost the power while the beam is pointing that direction. It’s the equivalent of scanning the horizon but pausing briefly to stare especially hard at the area of interest. Finally, the E-2D can temporarily turn off the rotating function and funnel all its considerable radar energy at a target."

From what I'm reading, it says that the E-2D has the ability to temporarily funnel its entire energy onto a single target, in order to "see" it better. The (vastly) increased energy being projected onto a single location seems like it should be able to generate a strong enough return to form a track.

Of course, the AN/APY-9 on an E-2D cannot be used this way in a general search. Like you said, it would be a spectacular and ignorant misuse of the system -- you would be able to focus on one single area, but leaving the other 359 degrees of the circle unobserved. Because of this, it appears that the E-2D would use its radar in the normal method while searching. As a LO target entered range of the E-2D, it would show up as a weak/intermittent target. Just like you said, although the target would be detected, it would be too weak to generate a return or guide a weapon. In order to generate a track, the E-2D would use its electronically scanned array to focus all of its energy on a single target, improving the strength of the return enough to generate a track.

Also, I realize that the RCS figures of the J-20 and PAK FA are not known. However, since there is no other information about their RCSs, the various estimations give us some sort of idea what their RCSs may be. Obviously, no one knows the actual RCSs.

 

[Todjaeger]

"Why is this a major advance? It turns out that continuous scanning across the full 360 degrees limits power applied in any one direction. To keep the scan revisit rate relevant, the radar can only spend a brief instant on each degree of arc before sweeping around again. That is usually more than enough to pick up a target and establish its track. But what if the target is especially hard to see – i.e., stealthy? Or what if it is flying low in ground clutter? In that case, what’s needed is a focused beam that dwells longer, sending more energy in a specific direction. Increased energy transmitted out produces more energy received back and a sharper radar return.

The E-2D for the first time combines both modes in a naval platform. Electronic scanning enables the radar to function both as a rotating beam generating 360-degree coverage, and as a staring beam that can pour radar energy into tracking even the smallest, stealthiest targets. As a result, the E-2D radar is so flexible that its crew can rapidly switch between three main modes of operation. First is the classic rotating beam, ensuring the strike group has no blind spot. Second is a mode which continues the rotation but carves out a 45-degree slice, for example, where power is enhanced. The crew can focus the beam at the direction of a known or cued threat and boost the power while the beam is pointing that direction. It’s the equivalent of scanning the horizon but pausing briefly to stare especially hard at the area of interest. Finally, the E-2D can temporarily turn off the rotating function and funnel all its considerable radar energy at a target."

From what I'm reading, it says that the E-2D has the ability to temporarily funnel its entire energy onto a single target, in order to "see" it better. The (vastly) increased energy being projected onto a single location seems like it should be able to generate a strong enough return to form a track.

Of course, the AN/APY-9 on an E-2D cannot be used this way in a general search. Like you said, it would be a spectacular and ignorant misuse of the system -- you would be able to focus on one single area, but leaving the other 359 degrees of the circle unobserved. Because of this, it appears that the E-2D would use its radar in the normal method while searching. As a LO target entered range of the E-2D, it would show up as a weak/intermittent target. Just like you said, although the target would be detected, it would be too weak to generate a return or guide a weapon. In order to generate a track, the E-2D would use its electronically scanned array to focus all of its energy on a single target, improving the strength of the return enough to generate a track.

Also, I realize that the RCS figures of the J-20 and PAK FA are not known. However, since there is no other information about their RCSs, the various estimations give us some sort of idea what their RCSs may be. Obviously, no one knows the actual RCSs.

There seems to be a fundamental disconnect in part of what current LO aircraft do (how they are LO...) and how most military surveillance radars work.

Many radars are able to detect very small RCS targets, weather radars for instance, are often keyed to look for the very small RCS of clouds, moisture and air pockets. When detected, there might be many small RCS returns over a scanned area. The radar would not be able to identify precisely where the detected cloud or air pocket is, and in fact there would likely be many such detected phenomenon within the scanned area.

Many military radars are tuned to ignore such returns, as the sheer number and imprecision in tracking can overwhelm a surveillance system.

With an AESA or MESA and aircraft like the E-2D could potentially focus on beam energy at a specific questionable contact, to attempt to determine what it was and establish a track for it. However, the E-2D still has the problem of detecting the questionable contact and deciding to investigate. Without some additional supporting systems and/or using more energy, the E-2D would have a difficult time determining if a questionable contact was something natural like a whisp of cloud, or a hostile LO aircraft. If the contact was a LO aircraft, and the E-2D decided to investigate further and concentrate a beam, then the situation could work as described above. However, if the E-2D has four such contacts, would it have sufficient time to investigate all of them? How about if there were a hundred such contacts?

To get a good graps of what I am talking about, look at an electronic map with a weather radar overlay, particularly when stormy, rainy or windy day is predicted. Those areas where demarcation lines are to indicate some sort of weather activity are more or less where weather radar systems detect returns. They generally cover a rather broad area, and the radar operator would need to try and decide is the swarm of contacts weather, or a LO aircraft, or perhaps even both...

-Cheers

 

[mAIOR]

Isn't that assuming clouds will have the same speed as a LO target? because the doppler shift from both would be quite different. You may have LO features but if you're fast, you could stand out in the middle of the clutter.

 

[Burke095]

There seems to be a fundamental disconnect in part of what current LO aircraft do (how they are LO...) and how most military surveillance radars work.

Many radars are able to detect very small RCS targets, weather radars for instance, are often keyed to look for the very small RCS of clouds, moisture and air pockets. When detected, there might be many small RCS returns over a scanned area. The radar would not be able to identify precisely where the detected cloud or air pocket is, and in fact there would likely be many such detected phenomenon within the scanned area.

Many military radars are tuned to ignore such returns, as the sheer number and imprecision in tracking can overwhelm a surveillance system.

With an AESA or MESA and aircraft like the E-2D could potentially focus on beam energy at a specific questionable contact, to attempt to determine what it was and establish a track for it. However, the E-2D still has the problem of detecting the questionable contact and deciding to investigate. Without some additional supporting systems and/or using more energy, the E-2D would have a difficult time determining if a questionable contact was something natural like a whisp of cloud, or a hostile LO aircraft. If the contact was a LO aircraft, and the E-2D decided to investigate further and concentrate a beam, then the situation could work as described above. However, if the E-2D has four such contacts, would it have sufficient time to investigate all of them? How about if there were a hundred such contacts?

To get a good graps of what I am talking about, look at an electronic map with a weather radar overlay, particularly when stormy, rainy or windy day is predicted. Those areas where demarcation lines are to indicate some sort of weather activity are more or less where weather radar systems detect returns. They generally cover a rather broad area, and the radar operator would need to try and decide is the swarm of contacts weather, or a LO aircraft, or perhaps even both...

-Cheers

It would seem that much of the clutter you mention could be rejected with pulse-Doppler look down/shoot down radar. Pulse-Doppler basically detects the speed of different objects, and rejects those that do not fit in with the parameters typical of a hostile target. Because cloud cover is quite different speed-wise from a jet aircraft (i.e. -- cloud cover doesn't have a cruising speed of 600+ miles per hour), it would be rejected. If I'm not mistaken, most of the low-RCS clutter that could hide a target would be rejected because of this feature.

As far as having multiple targets, that does present a genuine problem. Being as the E-2D has a peak power output of 450 kVa (apparently this level can be maintained for a period of three hours), it is definitely possible that it could focus its energy on several individual targets (using its electronically scanned array). Of course, this wouldn't allow as much energy to be radiated at each individual target, but with so much energy to utilize, a sufficient portion could remain for the E-2D to deal with several targets at a time. The ability to tailor the radar beams to radiate towards a specific set of targets seems to be a huge advantage AESA radars have over their mechanically-scanned cousins.

Of course, if what I'm saying is complete garbage, please feel free to bluntly tell me so. :tomato I tend to not mind when people tell me my observations are hogwash -- it allows me to learn more than I would if I was not told which observations are valid and which are not. I'd say I've learned quite a bit from this thread alone.

Because of the valuable learning experience your answers have given me, I'm happy to thank all of you for the responses!

 

[gf0012-aust]

It would seem that much of the clutter you mention could be rejected with pulse-Doppler look down/shoot down radar. Pulse-Doppler basically detects the speed of different objects, and rejects those that do not fit in with the parameters typical of a hostile target. Because cloud cover is quite different speed-wise from a jet aircraft (i.e. -- cloud cover doesn't have a cruising speed of 600+ miles per hour), it would be rejected. If I'm not mistaken, most of the low-RCS clutter that could hide a target would be rejected because of this feature.

depending on the target, look down radar/sensors can be spectacularly ineffective. simple shifts in sea state can alter return integrity, so there's no assumption that an AWACs on cruise missile alert will be able to sift and sort with confidence.

The algorithms to do these "simple" sorts vary in quality and capability.

As far as having multiple targets, that does present a genuine problem. Being as the E-2D has a peak power output of 450 kVa (apparently this level can be maintained for a period of three hours), it is definitely possible that it could focus its energy on several individual targets (using its electronically scanned array). Of course, this wouldn't allow as much energy to be radiated at each individual target, but with so much energy to utilize, a sufficient portion could remain for the E-2D to deal with several targets at a time. The ability to tailor the radar beams to radiate towards a specific set of targets seems to be a huge advantage AESA radars have over their mechanically-scanned cousins.

the principle advantages of a digital system are about concurrent and selective steerage - and the capacity to pull feeds from a number of other sources in useful timeframes - it still has to sort the dross, and thats no mean feat

 

[gf0012-aust]

Isn't that assuming clouds will have the same speed as a LO target? because the doppler shift from both would be quite different. You may have LO features but if you're fast, you could stand out in the middle of the clutter.

1) track management does not necessarily translate to target lock (eg SR71 and hypersonic PGMs)
2) track management is about multiple verifiers to give confidence that something actionable can occur
3) a fast mover does not necessarily mean that the target you seek is the target you are shooting at

objects can appear on a screen that are completely bogus - the capacity to do this has been around for 50+ years and only becomes more finessed as each year passes.

 

[Todjaeger]

Isn't that assuming clouds will have the same speed as a LO target? because the doppler shift from both would be quite different. You may have LO features but if you're fast, you could stand out in the middle of the clutter.

AND

It would seem that much of the clutter you mention could be rejected with pulse-Doppler look down/shoot down radar. Pulse-Doppler basically detects the speed of different objects, and rejects those that do not fit in with the parameters typical of a hostile target. Because cloud cover is quite different speed-wise from a jet aircraft (i.e. -- cloud cover doesn't have a cruising speed of 600+ miles per hour), it would be rejected. If I'm not mistaken, most of the low-RCS clutter that could hide a target would be rejected because of this feature.

Not quite...

Pulse-Doppler relies upon multiple radar pulses being emitted and returned back to the radar antenna. The avionics package associated with the radar then analyzes the returns using an algorithm to essentially sort through what came back from various returns to decide what was stationary, what was moving, how fast, etc.

Now with a LO target, the radar antenna might only get one, or a few pulse returns off the LO object. Depending on the computing power available attached to the radar and the quality of the algorithm, that might well be insufficient for the radar to determine that the LO object was there, nevermind that it was the same object, or be able to provide any sort of vector.

A way to think of radar is to imagine it like using a stop-motion camera, then having someone analyze what objects are the same and what are different across the various frames. With a high enough sample rate, things can look like they are in motion, even though in each of the photos taken, the objects are stationary on the film. This is actually where something like AESA can come into play for radar, allowing a much faster refresh rate than a mechanically steered radar antenna aboard the E-2C or E-3. Now an example where something like a LO object could come into play, would be in a 30 second long stop-motion video. At the standard frame rate of 24 frames (images on film) per second, there would be a total of 720 discrete frames/images, which when played together gets assembled by the brain to look like a motion video, instead of all those different still pictures. Where this is applicable for LO objects would be if out of those 720 different frames, a dozen of them had managed to capture the LO object, the viewer would only see the LO object if all dozen frames were right next to each other, and the viewer would only see if for a half-second. If the dozen frames were evenly distributed across the total video, then the viewer would likely not even see the LO object at all. Some good examples of the phenomenon would be for people to get some of the old black & white Walt Disney or Warner Brothers cartoons, and go frame by frame. Some of the videoes have the cartoon characters looking and doing things distinctly different from what one sees watching the cartoon in motion.

What the current set of LO technologies and techniques seeks to do, is allow so little information to return to the sensing system that the system then rejects the LO object as being a 'false positive'.

-Cheers

 

[Bonza]

That's a fantastic analogy Tod. I hadn't visualised it in that way before. Cheers very much for the explanation and adding to the discussion.

 

[colay]

That's a fantastic analogy Tod. I hadn't visualised it in that way before. Cheers very much for the explanation and adding to the discussion.

Seconded.
Taking it further along the kill-chain, signature management measures will be similarly detrimental to RF missile seeker effectiveness, if not more so, given power and size constraints.

 

[mAIOR]

What the current set of LO technologies and techniques seeks to do, is allow so little information to return to the sensing system that the system then rejects the LO object as being a 'false positive'.

-Cheers

Brilliant, thanks a lot for this analogy. It's permanently stored in my brain. Bloody brilliant mate.

Still, an AESA will have advantages when compared to PESA or others in detecting LO targets won't it?

Apparently the best way to detect a LO target is to have a guy near the airport where they're stationed who rings you when they are taking off and tells you their approximate heading.

Cheers

 

[Todjaeger]

Seconded.
Taking it further along the kill-chain, signature management measures will be similarly detrimental to RF missile seeker effectiveness, if not more so, given power and size constraints.

Yes and no. It sort of depends on who the opponent is and what sort of supporting systems they have and can utilize. The seeker(s) in the inbound AAM are of necessity going to be smaller and lower-powered that what is available to be mounted in aircraft, surface vessels or ground stations, but...

It is possible that the missile might also employ a datalink, so that it can be directed by an offboard sensor to the LO aircraft, if the sensor system is able to track/target the LO aircraft of course. It also might be possible if the AAM has a multi-mode seeker or multiple different types of seekers, for the onboard sensor system to be able to collate sufficient return data to target something, especially if there is also offboard help.

As for AESA and PESA being more effective... They certainly have the potential to. Part of this stems from such systems being able to re-scan a given area much faster than a mechanical array could. However, the computers which process the return data can still end up filtering out contacts. Where some of these ESA's start to come into their own is in either rapidly re-scanning or maintaining an area scan, giving the potential for more anomalous returns to come back and not get rejected as a false contact.

The system might still be able to tell the operate SFA what it is, but there could then be the potential for an operator to start to concentrate some of the array resources on ID'ing the anomaly, which could then lead to tracking/targeting. Or it might lead to having a fighter flight be sent into an area to take a closer scan and/or look.

-Cheers

 

[mAIOR]

Yes and no. It sort of depends on who the opponent is and what sort of supporting systems they have and can utilize. The seeker(s) in the inbound AAM are of necessity going to be smaller and lower-powered that what is available to be mounted in aircraft, surface vessels or ground stations, but...

It is possible that the missile might also employ a datalink, so that it can be directed by an offboard sensor to the LO aircraft, if the sensor system is able to track/target the LO aircraft of course. It also might be possible if the AAM has a multi-mode seeker or multiple different types of seekers, for the onboard sensor system to be able to collate sufficient return data to target something, especially if there is also offboard help.

As for AESA and PESA being more effective... They certainly have the potential to. Part of this stems from such systems being able to re-scan a given area much faster than a mechanical array could. However, the computers which process the return data can still end up filtering out contacts. Where some of these ESA's start to come into their own is in either rapidly re-scanning or maintaining an area scan, giving the potential for more anomalous returns to come back and not get rejected as a false contact.

The system might still be able to tell the operate SFA what it is, but there could then be the potential for an operator to start to concentrate some of the array resources on ID'ing the anomaly, which could then lead to tracking/targeting. Or it might lead to having a fighter flight be sent into an area to take a closer scan and/or look.

-Cheers

Yeah so, LO platforms will still win the awareness battle for some time to come. As in, they'll know what is out there before the out there knows where or how many LO platforms there are.

 

[Todjaeger]

Yeah so, LO platforms will still win the awareness battle for some time to come. As in, they'll know what is out there before the out there knows where or how many LO platforms there are.

Most likely yes, given the current work being done on the F-35, but not necessarily.

In the Situational Awareness (SA) battle, there are essentially three components, which themselves fit into the overall battlespace.

These can be described as harvesters, comms, and actionable assets (or shooters). In a proper system, platforms themselves will contain more than one of these components.

Using the F-35 as an example, it can act as a harvester using the APG-81 AESA with LPI, the EODAS and EOTAS to given the pilot a fairly comprehensive picture of what is in the air and on the ground.

With the comms systems built into an F-35, the information gathered can also be relayed to other assets. In a fully datalinked air-ground battle, that is something which can ruin an enemy tanker's day. Not do they need to worry about hostile ground troops armed with AT weapons, and the potential for air attacks from helicopters and fast jets, but now ground weaponry could be queued to targeting data from aircraft. Imagine how a tanker might feel if suddenly a few artillery shells start bursting within a few metres of their position...

Lastly, the F-35 can take action upon what it 'sees' or gets via datalink.

The LO portion of the F-35 (and the F-22, B-2, F-117, etc) was all to degrade the opposing platforms/systems ability to 'see' the shooter asset. It in and of itself does not increase the asset or system's SA. The F-117 itself is a fairly good example of this. The LO treatments meant that under normal, proper (and properly planned) combat ops, the F-117 was very difficult for a hostile force to engage, because the hostile force knew SFA where the F-117, or even if one was present. At least until bombs started dropping and going off anyways. However, the F-117 had basically no onboard sensors for it to detect or target things on its own, and did not have a way to send or receive targeting information from offboard assets.

Under such circumstances, if the opposing harvesters and comms were up to the task, a F-117 could have been shot down by a P-51 Mustang. With the way things are currently done, if two sides have equally good comms and harvesters, but one uses LO assets and the other does not (or not nearly as LO), then the side making use of LO will have an advantage, all other things being equal.

-Cheers

 

[mAIOR]

There was a good picture for that in the waypoint magazine article on Stealth.
http://www.harpoonhq.com/waypoint/articles/Article_021.pdf

Page 13 and 14.

So again, good SA is king. That example of artillery shells is like the one using AEGIS in which a dedicated command ship can use all assets in a fleet under it's command. It's very good policy in terms of resource management and should prevent overflowing by multiple contacts. Judging by the mass bomber and cruise missile attack present on Soviet doctrine, it's clearly a good way to counter it. CEC should further increase this capacity and it'll make an American Carrier battle group even more powerful than they are now. It's information like this that shows just how vast and complex military doctrines are and how it makes no sense arguing if this fighter is better than that.

Also, you can begin to understand why the Raptor is being given a run for it's money. I think it's the comms scenario where the Raptor shortcomings come to bear (basing myself on what was said here and with the German comments after RF2012 that it was hard to coordinate with the raptors due to incompatibilities with the data link systems). In a way, if I got this right, the F-22 resembles more the F-117 than a true 5th gen aircraft (or maybe the F-35 already is going beyond 5th gen aircraft).


Also, on the F-35 part, there's one more argument against Canadian acquisition of the CF105 (even though I have to agree with one of it's protractors that it's always better for a nation to develop their own weapon systems).

Also, how feasible is it to integrate 4+ gen assets into such a battle system? Can we expect Vipers with this kind of SA or is it just not worth the effort?

 

[gf0012-aust]

So again, good SA is king.

whoever sees first and sees the most gets the advantage in dictating the fight

 

[NobodyMinus]

I thought this was an interesting question, and did some math to try and get good numbers. the radar equation is extremely annoying to read in a forum that does not support latex, so bear with me.

R=(((Power Emitted)*(Antenna Gain)^2*(Wavelength)^2*(Radar Cross Section))/((Minimum power received)*(4pi)^3)))^(1/4)

Holding everything but range and RCS contant, and setting up a proportion, we get

(RCS1)/(Range1^4)=(RCS2/)(Range2^4)

Now, we can simply take the RCS/Range estimates of several modern radars and scale them to the RCS of our planes. We'll do it for SAM radars, AWACS radars, and fighter avionic radars. We're only going to use the F-22 and F-35 as targets because bringing up any guess at the J-20 or PAK FA's RCS always sparks an enormous and annoying debate.

Let's do the 91N6E radar of the S-400 against the F-35's RCS first.

Before anyone whines at me about it, yes I am aware of the radar shadow effect. The question was about the maximum detection range of such systems, not about whether or not they would be effective at those ranges during SEAD operations.

The claim I've hard most often about the 91N6E is that it can detect a 1m^2 target at a range of about 600km. The claim I've heard most often about the F-35 is a frontal RCS of about 0.001m^2. Plugging these numbers into our equation gives us a range of about 107km, which is quite a distance. Doing the same with the F-22's 0.0001m^2 gives us a range of about 60 km, still quite a ways away.

I can't find a good estimate for MEAD's range, so I'm excluding it.

Now let's move on to AWACS. I can't find a good estimate for the A-50's range so I'm excluding that and moving straight to the E-3

The American E-3 sentry carries a AN/APY-2 with a stated range of around 375.5km. This gives us the Lightning at a range of around 67km and the Raptor at a range of around 37 km.

Finally, let's address fighter avionic ranges.

The N050's supposed to have a range of about 160km against a 1m^2 target. This puts Lightning detection at around 28km and Raptor detection around 16 km.

APG-77 and 81 should detect around 42km for the Lightning and 24km for the Raptor.

Keep in mind that these numbers are based off of incredibly rough math, and what at best can be called estimates of numbers. Also note that they do not account for loss at range, which is a fact that's hard to estimate without knowing more about the radar

 

[Guynumber7]

What about passive systems such as Kolchuga?

And what about modern russian ground based radars such as the S-400s radars?

 

[Todjaeger]

What about passive systems such as Kolchuga?

And what about modern russian ground based radars such as the S-400s radars?

What about them?

Kolchuga is a distributed ground-based ESM system which is dependent on RF emissions from a source being detected by multiple receiver systems. Given the limits imposed on any ground-based system (curvature of the earth, etc) and the fact that EMCON reduces what is available for Kolchuga to even try and detect... more seems to be getting made about it than is really warranted.

As for the radar systems in an S-400 unit, they also run into limitations by being ground-based. More powerful antennae and processors can help boost the radar range and ability to 'see' through clutter, but the advantages still remain with LO aircraft.

-Cheers

 

[mAIOR]

well, the advantage remains with the one who has a more effective integrated system. SEAD missions against a IADS with S-400 will be no walk in the park. Even S-300s present a big threat to nowadays assets. Still, looking from another angle, imagine how much harder it will be to tackle those systems with assets that are not LO or VLO. their survivability will drop considerably. Also, VLO platforms will increase the cost of a system that is meant to stop them simply because their effectiveness goes from 600 Km to 100. You'd need 6x more S-400s to properly cover the possible ingress route of an F-35.
One simulation APA could try to run would be to calculate the attrition rate of a Super Hornet vs an F-35 when tackling such a system. Heck, I have Harpoon 3, I can do it myself

 

[Todjaeger]

well, the advantage remains with the one who has a more effective integrated system. SEAD missions against a IADS with S-400 will be no walk in the park. Even S-300s present a big threat to nowadays assets. Still, looking from another angle, imagine how much harder it will be to tackle those systems with assets that are not LO or VLO. their survivability will drop considerably. Also, VLO platforms will increase the cost of a system that is meant to stop them simply because their effectiveness goes from 600 Km to 100. You'd need 6x more S-400s to properly cover the possible ingress route of an F-35.
One simulation APA could try to run would be to calculate the attrition rate of a Super Hornet vs an F-35 when tackling such a system. Heck, I have Harpoon 3, I can do it myself

Not quite.

A strike package can use some assistance from other assets (ISR, EW, etc) but with a properly mapped out route to the target, the need for integration from other assets is reduced.

A GBAD system however needs to have a significant amount of integration and cross communication to attempt to track and engage an inbound strike package. Especially if that package is LO and/or uses standoff munitions.

A good example of what I mean relates to the use of LACM's. Something like a TacTom flying at ~15 m cannot be detected by a radar array with a 10 m antennae until the TacTom is only ~29 km out. Depending on any irregular and/or intervening terrain features (ridges, hills, trees, etc.) the actual accuracy of the radar and processors, and the skill of the operators, that range can be further reduced.

Assuming the S-400 system was the target (which it could be, being a theatre-level SAM system) the S-400 would have at maximum ~2 minutes to detect, engage and destroy the inbound TacTom, before the S-400 would get damaged, disabled, or destroyed.

The only way to increase that 2 minute window would be to have radar systems positioned to allow detection further way than 29 km. Use of additional S-400 systems would not really help, because they still would only have a detection range of ~29 km give a TacTom's flight profile, and they would also be subject to being targeted.

Now if one were to consider the application of deploying a newer generation of standoff munition where efforts have been made to reduce the RCS and munition signature like Scalp, Storm Shadow, JSOW, JASSM, etc... Then the radar operators will have even more difficulty in detecting the munitions so that attempts can be made to engage them.

-Cheers