For anyone who's interested. This is an informative post from
@gambit
Is it possible to intercept Brahmos with a CIWS ?
Gambit's answer : Sure, but the problems of detection and tracking remains. You need to keep in mind that CIWS will be at ground level, therefore most susceptible to line-of-sight issues. When the Brahmos breaks horizon, the gun will have only literally seconds to reorient itself and fire. This short time span require equally precise radar information as if you are relying on a missile's radar to make its interception.
Question by me : lets say that the radar can track the target at distance of 8km but the gun can engage at 3 km, so can the target be intercepted when it's speed is 2 km/s ?
Gambit's answer : Assume radar tracking and gun reorient is perfect. It does not matter if target is supersonic. If the gun can engage at 3km, which in this case the assumption is head-on, then target speed is not an issue. The gun radar will calculate target speed, estimate when it will reach that 3km point, then fire just before the target reach that 3km point. If radar tracking and gun response are perfect, then bullets and target will meet at 3km distance out.
You should understand that in a head-on intercept, and continue to assume that tracking is perfect, the only reason why target approach speed is important is
IF you want to avoid shrapnel. Because the intruder is coming so fast, even if you successfully hit him, there is still forward momentum at supersonic speed for a lot of small masses, still capable of doing a lot of damages if not kill something/someone.
So if we return to that 3km engagement distance, if radar tracking and gun reorient is not as good as you like, even though your bullets may intercept the intruder, that interception may be at 100 meters instead of 3km, spraying you with supersonic shrapnel. But let us say that your AWACS alerted you to a supersonic intruder, your gun reorient to the indicated direction and your gun radar begin transmitting. The moment the supersonic intruder breaks your horizon view, gun radar will have a solution and you will have interception at 3km distance out.
If you are defending something else that the intruder is going after, then the gun solution will lead the intruder, in other words, the bullets will be at an estimated point
AHEAD of the intruder's flight and you still will have an interception at 3km distance out. In this situation, the lead depends on the off angle between you and whatever it is that you are defending.
Source:
https://defence.pk/threads/brahmos-cant-be-intercepted-in-next-20-years.258714/page-11#post-4425874
Brahmos isn't the first hypersonic AShM. Similar Russian systems have been around for some time and NATO has continued to rely on the usual Gun and Missile based CIWS for their interception.
