In hindsight, the radar’s absence in Japanese carriers was the key. Ship-borne radars were yet to be introduced in these carriers. So, American aircrafts were able to bomb Japanese carriers undetected. But American carriers had been fitted with ship-borne radars, using which these could detect Japanese aircrafts beforehand and launch their aircrafts to defend in the nick of time.
Now, desperate Japan was looking to neutralise American carriers. To do so, some Japanese pilots rammed their aircrafts, fully-loaded with bombs and fuel, into American carriers, in what is called Kamikaze Attack. All these modes of attacks served as lessons for USN. When it started its ambitious carrier building and operating programme, air defence was given utmost priority.
Further to cement the importance of air defence, the USSR (of which the present Soviet Union was a part) entered into the picture as the newfound adversary of the USA to fight Cold War, a war fought without pulling a shot. The USSR sensed the challenging supremacy of the American carriers and fielded the deadly adversary of the carriers, the cruise missiles.
Having been developed inspired by Kamikaze aircrafts, cruise missiles offered a convenient means to attack a carrier. Earlier cruise missiles were just unmanned Kamikaze aircrafts.
From the cost perspective, a cruise missile costs a fraction of a carrier. But it is a very viable weapon, capable of being launched from bomber aircraft, warships and submarines. Incidentally, many of the early Soviet cruise missiles had nuclear warheads, sufficient enough to melt the entire steel present in the CSG.
The Soviet scheme was to simultaneously launch these missiles from submarines and bombers against the carrier from very long distances. Navigation computers of these missiles were programmed in such a way that all cruise missiles reached the carrier at the same time but from different directions. This was called the saturation cruise missile strike plan of the Soviet. Even if one cruise missile would hit the target, that would have been sufficient. This changed the situation in favour of the USSR.
Air defence warfare capabilities of the CSG have been on constant updates and upgrades all these years. Today, air defence systems of an American CSG can be termed as the most superior system in the world. Protecting the CSG from cruise missiles and cruise-missile-launching aircraft is called air defence warfare.
Air defence operations are carried out in four phases.
Phase I: Fighter aircraft and AEW aircraft combo
The first line of defence of the CSG is carrier-borne F-18 combat aircraft, which can operate far away from the carrier and shoot down enemy bombers before they launch cruise missiles. But these cannot find bombers quickly, because they do not know their exact location.
Onboard radars of F-18 aircraft can accurately scan specific sectors and specific altitudes but not all sectors and altitudes. To guide these towards incoming bombers, a dedicated airborne early warning (AEW) aircraft (also carrier-borne) is used.
These AEW aircraft, named E2, have huge radars. An inverted saucer-like structure on the top is the radome for the radar antenna. Radome is a structure made of radio-transparent material to protect the radar antenna from the environment. Inside this radome is the rotating antenna of the high-power UHF Doppler radar.
This radar can detect and track multiple threats on the sea and in the air. It can simultaneously and automatically detect and track 2000 targets, spread across the air and sea.
The aircraft keeps tab on an area of over twelve million cubic kilometres (three million cubic miles). Not only that, it can precisely track cruise missiles that fly low enough, as if skimming the water surface. Being a crucial component for the defence of the carrier, this radar is highly capable of resisting the jamming efforts of the enemy.
These aircraft maintain a surveillance patrol far away from the carrier and act as a command-and-control (C2) station. These see what the radars of the CSG cannot see. If AEW aircraft detect any enemy bombers at a long range, these communicate the same to the carrier through a data link. Immediately, F-18 combat aircraft from the carrier are scrambled. These take off and race towards incoming enemy bombers to intercept and stop these from launching deadly cruise missiles. When F-18 aircraft reach their area of responsibility, AEW aircraft vector these towards the threat. F-18s intercept and shoot down bombers. There are four such AEW aircraft on a carrier.
Phase II: Air search radars and fighter aircraft combo
Air defence operations relying on this combination is a grave scenario. It occurs when the AEW aircraft itself has been shot down. This scenario is very much possible if the incoming enemy aircraft force is large. In this case, CSG radars are the only means to detect enemy air targets. For this, the carrier has two air surveillance radars: a 2D radar and a 3D radar.