India has to come up with its own solution to its own unique threat from Pakistan. The west like US/Israel or our friend Russia have come up with products for their own threats. With a range of 600 kms the S-400 radar networked with AWACs, Aerostats and a must have satellite based missile launch early warning system will enable the 400 km range 40N6 from the S400 to get to any Pakistani missile launch. We do need 40N6 surely which have an effective range of 215 nautical miles which is approximately 400 km (398.18 km to be precise)
12 S-400 batteries placed at a distance of 100 kms apart will cover the entire border from Srinagar to Kutch with overlapping and a very tight net of coverage making it very difficult to penetrate expecially for CMs. Also the inside indian airspace coverage helps us a lot.. Another 15-18 at a distance of 200-250km apart each can cover rest of the country much better including key installation coverage. Frankly India needs not 12-15 to cover the whole Subcontinent rather approx 30 for a very sound and accomplished coverage PAN India and another 2 in Andaman & Nicobar so a total of 32 systems for around 16-17Billion dollars.So in all we need at least 8 regiments plus preferably 10 regiments of S-400.
Over time we must get the HTK missiles of S-500 particularly the 77N6 N/N1 missiles and see what can be upgraded in S400 to more of S500 standard. If possible procure out of 30 some 10 systems of S500 standard and deploy few of such systems in central, southern, eastern and one in Andaman & Nicobar too.
Simulations will have to be run to ensure that the 40N6 accelerates fast enough to intercept Pakistani missiles while still in the boost phase or in the early mid course phase preferably before they deploy countermeasure and decoys but with a maximum intercept altitude of 185 kms it should be capable of intercepting these short range missiles even during the mid course of their relatively short flights. Even if say like Shaheen 2 is given higher apogee with 1/3rd range, we have a much better chance to intercept such threats too.
THE 40N6 MISSILE
The second missile added to the S-400 is the new 40N6, a long range weapon with a cited range of 215 nautical miles, equipped with an active and semi-active homing seeker, intended to kill AWACS, JSTARS and other high value assets, such as EA-6B/EA-18G support jammer.
The range improvement to around twice that of the 48N6E2 suggests a two stage weapon, or a much larger motor casing with a larger propellant load.
To date no images of the 40N6 missile, launcher container or TEL have been made public.