Patrol aircraft, AEW aircraft, high-altitude patrol drones and possibly stealth drones, aerostats, among others.
This update of the carrier's location cannot come from the ASBM missile launcher, because due to the curvature of the Earth, it is not in a direct line of sight with the OTH target, which implies that this update would have to start from a platform that is in direct line of sight of the target.
This platform needs to be in direct line of sight with the target and connected directly to the missile. The fact is that this platform would have to remain "on station" until the ballistic missile is able to take over and acquire the target on its own. And this in an extremely challenging environment, which is being inside the defensive bubble of a CSG that has at least 5 to 6 Aegis destroyers and cruisers, plus the aircraft carrier itself, plus about 70 to 80 aircraft, including fighters equipped with AESA radars and long-range air-to-air missiles, AEW also equipped with long-range AESA radars and some specialized electronic warfare aircraft (EA-18G) that can act defensively, circling the CSG and jamming enemy communications, including satellite communications.
In other words, Iran or any country that truly has a full ASBM capability necessarily needs a complete dedicated ISTAR system.