Sir, Let me explain
General Note
S400 is for every aerial threat right from a missile to a jet to awacs to drone. The idea is complete aersopace supremacy over the intended range of operations (400 km radius with 600km detection). Of course it has limitation of intercepting ICBM class which Russia is trying to counter by Prometheus (S-500)
Quasi BM, CM and all aerial threats
S400 can encounter Iskander M (QBM) (The Russian Iskander-M cruises at hypersonic speed of 2100–2600 m/s (Mach 6–7) S400 also engages Yakhont/Onix as part of its strategy against CMs and was always planned as countermeasures against Iskander/Yakhont type missiles (even in S300 later variants stage and a regime where Russia had supplied the missiles and say west getting hold and reverse engineering it and using it against Russia). Now Iskander follows a very very flat path and is a dangerous quasi ballistic missile and other ones are cruise missiles. The quasi ballistic missile flies at a different path than a typical BM and thus harder to track and engage. It also is manouverable and may posses decoys of some sort.A Yakhont interception takes care of Brahmos part. On top if S-400 misses, the multi tier system allows Barak 8 (Normal and extended range) Land version as part of Indian BMD plan to take part and stop the supersonic CM. And i dont think we have seen something like that in South Asia as of yet (Both QBM and Supersonic CMs).
Also, S-400 Triumf are intended to destroy opposing stand-off jammer aircraft, AWACS/AEW&C aircraft, reconnaissance and armed reconnaissance aircraft, cruise missile armed strategic bombers, cruise missiles, Tactical, Theatre and Intermediate Range Ballistic Missiles, and any other atmospheric threats, all in an intensive Electronic Counter Measures environment.
The popular idea of shooting cruise missiles, anti-radiation missiles or standoff missiles at the battery, assuming its location is known, is only viable where such a weapon has a sufficiently low radar signature to penetrate inside the minimum engagement range of the SAM before being detected - anything less will see the inbound missile killed by a self defensive SAM shot.
The current Russian view of this is to sell Pantsir S1/S2 / SA-22 self-propelled point defence SAM systems as a rapid reaction close in defensive Counter-PGM system to protect the battery by shooting down the incoming missile if it gets past the SAMs. It comes as standard unit in one S400 unit with 4 in numbers as part of a single unit price of S400. On top, we will also deploy Akash, Spyder and other multilayered shield when integrated with Indian BMD). It implies if india buys 12 units of S400 we may have 48 Pantsir units too.
In case threat emerges the command post will based on its calculations wake up specific batteries, their numbers, select the missiles and give them orded to fire. Afterwards SAM systems will change their positions while being guarded by other ones in "sleeping" mode. Enemy will have huge problems locating SAM systems and guiding their fighters and CM to its targets because IAF fighters will roam the skys keeping on distance .
For Decoy detection
Signature analysis. combining data from its sensors, compare it with available target model, make decision then attack. (implying a robust command center and high quality radar for detection)
Now for ABM role
First thing: The new 40N6 missile guarantees a direct hit on a target at a range of 400 kilometers and
at heights of up to 185 kilometers – effectively near space.
Russian S-300 missile systems capable of targeting near space 'enter service' — RT News
That said, that 185 kms altitude is probably of the domestic version. Export version maybe less too.
Second thing,
There are three places you can intercept a ballistic missile... at launch... which is easiest as all the warheads are together so even if the missile carries 20 warheads it only takes one hit to take them all down.and of course the target is easy to spot as it has an enormous ball of fire at its base as it climbs.
The second place to intercept is between the target and launch pad for a mid course intercept, this is harder because the target is at full speed but not burning rocket fuel so harder to spot and flying high. The advantage is that you don't need to operate within enemy territory to take the shot.
And finally you can locate interceptor missiles near the target for terminal interception... for 20 warheads you have 20 targets, and they don't start glowing till they enter the atmosphere, but it is your air space and with plenty of warning you have the advantage that they are coming to you.
Third Thing,
S-400 again is (like later new S-500 ) designed to intercept high altitude for high end IRBM type targets. (a mid course interception step 2)
S-500 was always designed for High Altitude terminal defense of ICBM targets and mid-course for IRBM targets.
S-400 and alike Russian AD systems are meant to simultaneously work with ECM systems meaning enemy radars are supposed to be blinded anyway as 40N6 and 48N6 steam rolls its way towards the target. From the official Almaz-Antey leaked about the existence of the passive guided S-400 missiles
and many other things about the S-400 missile system remains a secret till this day but one thing is for sure, Russian generals are extremely happy about it.
A likely scenario would be that the S-400 is a high-tier anti-IRBM system when put into service but designed to evolve into a lower-tier anti-ICBM system (just under higher tiers S-500)
Now this fits Indian ABM perfectly and let us have a sound system clearly countering present threat from western border and have an aerial superiority via a combination of IAF jets and supremacy platforms like S400
SAm against SAm is for having a similar system to counter indian aerial threats..Aster is a good system and is also heavy cost. pak will need at least 5-6 such systems and i am sure not everything can be bought with price negotiations and line of credit. perhaps a better option would be Chinese HQ series due to line of credit availability as well as quicker deplyment.
Now officially i have never heard in any open source that say aerail threat from Pak is getting targeted at say 400 km range in Pak/India border airspace and 40N6 is fired and Aster 30 radar lights up (unlikely due to strong ECM measures) and aster 30 SAm fires a missile and takes 40N6 out...
That i feel needs a field testing... not heard before..
thats called Anti SAM btw
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