Sir, Please clarify if I've missed understood any.
1. Ballistic Missles in these days have sep ranging from 50 mts to 10mts. If they are supposed hit targets 50 km away, the'll adjust their path in endo atmosphere through terminal guidance. This is applicable for all kinds of RVs i.e., MIRV and MaRV
2. Even a ballistic missle alters its path just to hit 50 km away target, then I am sure that it will not escape the range of PDV.
3. Lets assume, the warhead has escaped PDV and AAD is supposed to take care of it.
3a)Let's assume a city in the form of circle radius of 50km for our convenience, 4 AAD batteries on 4 corners to cover 100% of the city with max protection.
3b)Assume an IRBM is fired, PDV missed the warhead, warhead is coming at mack 10 speed, AAD to intercept this warhead at 10 km height. We need to fire multiple PDVs and AADs to destroy incoming warhead
3c) Mack 4 Ashwin AAD missile will take 21secs(20 secs, but for my convenience I've taken 21) to reach the point(which is 25 km from the AAD battery)to hit the warhead.
3d)During this 21 secs warhead(IRBM travelling at mack 10 would go 70 km, ICBM travelling at mack 25 would go175km)our IRBM warhead will travel 70 km. It means at 80km altitude, just after PDV misses its target AAD Missles should be launched.
4. My point is even if we have an AAD missle with 100 km range, there is no point because we may not use it to full range of AAD, in my view if we could use it to the full extent of 25 to 30 km that would be great.
Contradiction with your (
@Scrutator) statement
1. AAD can only be used with range of 25 to 30km at max, even if AAD has more range it will not serve the purpose.
2. If warhead changes its target just by 50 km, it will be in PDV's range, and PDV's range is higer(read somewhere that it could be close to 200 km radius) and terminal guidance and re targeting a BM is no joke
Conclusion:
1. AAD is only for IRBMs not for ICBMs.
2. AAD is only at max range of 25 km.
3. For 1 warhead, we need multiple PDVs and AADs.
4. If 10 or more warheads fired at single target, atleast one will hit.