When entering terminal phase, the two seeker systems activate, the first is the monopulse active radar...
This is how a monopulse radar works...
Basically...A single signal is split into four and the target is supposed to be inside that shaded area. Less sophisticated ECM will not defeat a monopulse radar but who said the US is one of those 'less sophisticated'?
Article: Deceptive jamming against monopulse radars. - Journal of Electronic Defense | HighBeam Research - FREE trial
This three-part consideration of the deceptive jamming of monopulse radars ends with a discussion of the "cross eye" jamming technique. Several other deceptive techniques remain untreated, but those we have covered are representative. It is important to remember that chaff, decoys and denial jamming are also effective against monopulse radars.
RADAR WARNING RECEIVERS AND DEFENSIVE ELECTRONIC COUNTERMEASURES
Monopulse radars are notoriously difficult to jam and require more cunning techniques such as cross eye jamming. A cross eye jammer employs two deception repeaters which retransmit the impinging radar signal with set time delays. By situating the transmitting antennas at the extremities of the aircraft (eg out on the wings) and manipulating the time delays, the cross-eye jammer distorts the shape (and hence perceived direction) of the returned echo (wavefront). A monopulse track ing system aligns itself with the direction of the incoming return from the target and is thus driven off the target.
There are many other techniques to nullify a monopulse radar. The more sophisticated the electronics and avionics, the more robust and effective the ECM signals. For a monopulse radar, the target
MUST remain inside that shaded area and if one of the four receivers is deceived in any way, the monopulse system will believe itself to be out of calibration. The entire system then repeatedly reset itself, rendering the missile useless.
A sharp drop then happens, from 20-30 metres to 5-7 meters above the sea level, maintained by the radio or laser altimeter. This has the advantage of making it near invisible to the target ship because it is below the detection range, especially combined with the integrated jamming capabilities and low radar signature.
AWACS will detect the missile long before it reaches the fleet, probably detect the launch itself.
Third is the introduction of manoeuvring algorithms to make it harder for active ship defences to stop the missile. (9)
Which also limit its maximum range. Maneuvers
ALWAYS cost time and fuel.
So as long as the fleet's AWACS detect the missile, in less than five seconds, fleet defense, or even single ship defense for that matter, can launch chaff/flare defenses that will totally blanket the missile's sensors, even before the missile achieve what is called 'horizon break', that is the precise moment when a missile is supposed to catch the first glimpse of the a target. What happens is as the missile is happily cruising along and in an instant, it sees nothing but noise...That moment of detection of that noise is 'horizon break' when it sees something other than ocean surface. Same as if in that same instant it sees the target, which to its computerized mind, the target would look something like this...
All the surfaces and edges on a ship is recreated, hence those squares.
Rafael Anti-Ship Missile Defense System - Decoys
These lightweight chaff rockets are equipped with a programmable electronic timer to generate realistic targets, a few thousand of square meters in size, at ranges between 500 and 2000 meters from the ship.
A few chaff canisters can create an electronic blanket ten or more times the broadside area of a Nimitz class aircraft carrier, totally blinding the missile. Same for flare against IR sensors. So as long as the fleet is covered by AWACS, it will have ample time to deploy these defenses.
