What is NS? What is north point?

NS as in naval system?
But i really dont get what north point is...

See the link in my signature.

If you took two AWACS, broadly speaking, one on passive and one on active, the active one would pick up the passive one because it is looking for it, and the passive one would pick up the active one because it is broadcasting its radar. So you need a balance. Plus AWACS can turn their radars on and off very quickly, which will give them a bit of both aspects.

Radar satellites: Commonly known as RORSATs; Radar Ocean Reconaissance Satellite, these are satellites in low earth orbit that use a radar to scan the ocean from space. Unfortunately, their resolution is very low, to the point where, like OTH radars, they may not be able to distinguish a cruiser from a tanker. Radar satellite technology is improving, but I don't rate its resolution or its reliability. It is certainly not what most RPers use it as, i.e. "Oh I found you with my satellites." Radar sats are definetly better than optical sats for doing this, but they're still not perfect, because there's no real way to distinguish what it is that you're looking at (contacts come up as pixels on a radar screen; on a high-resolution radar, an aircraft carrier could be 1000 pixels and a destroyer 100, but on a low-resolution radar, they both might be even 1 pixel) or even what nation's flag its flying under. They're also pretty much defenceless and can be shot down with ASATs within the opening days of a war.

Using EW equipment to scramble the lock of a missile. An anti-ship missile with an active radar that has a lock on your ship can be scrambled and so is likely to miss. Largely useless against missiles with inertial or IR terminal guidance

Chaff. Designed to spoof radars into believing there are hundreds of targets in the air so it locks on to one of them instead of the ship. Largely useless against missiles with inertial or IR terminal guidance.

2. Protection; The battleship is well protected with a lot of armour. It takes a large and powerful missile to penetrate the belt or deck armour of a well defended battleship.

Carriers on the other hand, are usually unarmoured, and for good reasons (it detracts too much from hangar space, and damage takes much longer to repair). A hit with a missile might just bounce off a battleship but might severely damage a carriers deck. While this seems crucial, its meaningless. The carriers deck is vulnerable. The battleship's sensor suites, its radar and targeting systems, are also vulnerable. They cannot be protected because you can't shield radar behind inches of steel. One missile hit to the superstructure might knock out the radar permanently and force the ship to withdraw or else go blind. So all that armour is absolutely wasted.

Once you turn your AEW radar off and on, you need to rebuild the picture of the battlespace, which takes time. Lots of time, on the order of tens of minutes

Technically correct, but ignores that satellites can be tracked, and are on mostly fixed paths, and thus can be avoided if there are only one or two.

Stuart Slade likes to point out how modern radar sets in missiles notice when something isn't behaving like a ship should (and Chaff clouds don't).

No it doesn't. The rule of thumb is that a well designed penitrator can punch through 6 times its diameter. For a small 12" warhead, that's 6 feet of steel. When I'm done that battleship will be swiss cheese.