Thing is though that the necessary countermeasures needed to defeat a swarm of LRASMs are also the same type of capabilities needed to defeat large drone swarms anyway, particularly in distributed detection and targeting capabilities of anti-aerial unit capable systems. Whether it be loitering anti-missile drones themselves, High-Powered lasers, extended range CIWS, enhanced ECM or combination of such systems these are the critical areas where Chinese R&D now has a decisive counterforce advantage over their US adversaries, even before taking into account possible long range counterfire options.
But it still needs to be detected.
Because the LRASM launch will occur over the horizon, it's difficult for the target to be certain it's under attack, especially since an aircraft like the P-8 or a Global Hawk can use passive sensors and may be out of radar range of the target ship. Not to mention American satellites equipped with synthetic aperture radars, which have the potential to designate targets for ships.
As for the LRASM's sensors to alert the target, it must use a combination of passive sensors and would only use radar in the event of bad weather or some infrared countermeasure. It has a passive ESM system that "listens" to radiofrequency radiation and classifies it.
For the missile to launch, the target must be detected with reasonable accuracy. There are three possibilities for target detection:
a) The target is detected by infrared emission or even visual recognition. b) The target is detected by a RWR because it is emitting signals, and again, it could be a P-8, a Global Hawk, an ELINT satellite, or whatever.
c) The target is detected by radar. It could be a P-8, a Global Hawk, a satellite like LaCrosse, a P-95, or whatever.
Let's look at each case individually -
a) Searching for a target at sea or on land using IIR or visual pre-scanning involves getting quite close to the target, we're talking about tens of miles. And a patrol aircraft or even a high-value UAV like a Global Hawk won't approach a TF at this distance to search for it with FLIR in times of war. Optical satellites don't search for ships.
The point is that this type of technique isn't for detection, but for recognition and identification. There's no way to achieve an IIR-based firing solution against a ship with area defense capabilities without exposing the platform to significant risks.
b) Yes, it is possible to locate a transmitter's position with an RWR at a distance of hundreds of miles, completely passively. The point is that what you see with this technique is "a transmitter," and this is different from finding a target.
You are the commander of a TF, with half a dozen ships, one or two of which are primary targets (aircraft carriers, landing ships, supply ships, area control), and the rest are escorts. What does the commander do? He places two or three escorts in open positions, 20 or 30 miles from the TF. These escorts conduct aerial searches over the TF region; they are the only ships transmitting and carrying the signals, and the only ones detected by the electronic reconnaissance onboard the patrol aircraft. In a coordinated manner, the escorts rotate at intervals of, say, 15 minutes. So, what the patrol aircraft sees are transmitters entering and leaving random positions. He knows that there is a TF in that region, but he does not know how many ships there are nor their precise location that would allow for a firing solution with anti-ship missiles.
c) The patrol aircraft, satellite, or whatever illuminates the TF with radar. By doing so, it knows the precise position of the ships (those that are transmitting and those that aren't) and also, depending on the radar quality, the type of vessel. This allows for a firing solution for an anti-ship missile.
The basic premise, then. Against a coordinated TF with area defense capabilities, a firing solution can't be easily achieved with IIR or just MAGE; you have to illuminate it at some point.
Now let's move on to the ship's CIC. You're there and realize that your ship has been searched, albeit briefly, by a radar (which could be in space, on a UAV, or patrol aircraft). We can even consider an LPI radar, which is simply more difficult to detect, but not "identifiable" as some believe.
Search by multiple measures (SIGINT) indicates that a missile attack is possible (although you don't know if it will happen). What does the ship's commander do? It accelerates to maximum speed and changes its course almost randomly, creating uncertainty between the position plotted during the search and the actual position minutes later, when the missile (if launched) will arrive in the target region.
This forces the attacking missile to search for it sooner, which in turn allows it to find it sooner.
The time between launch and arrival in the target region varies, of course, from missile to missile.
Let's assume that the ship accelerated to 25 knots as soon as it entered alert status with the radar search, which allowed the fire-to-fire solution.
LRASM: 600 km at Mach 0.95 gives about 31 minutes of flight.
In this time, the target can travel 23 km. The target may be within an uncertainty zone of 1,711 km2.
The LRASM's concept is likely to orbit the region and search for the target until it finally finds a firing solution and dives in for the final attack.
It has the advantage of being stealthy (but not invisible) and will hardly be able to hide from the ship's terminal defense during the final miles. Not to mention that while searching for the target, if it uses SAR, it will be detected, eliminating some of the tactical surprise.
These are different concepts, each with advantages and disadvantages.
I personally believe that the choice of an LRASM prioritized range for power projection situations over land, rather than classic anti-ship missions, which will still be fought at up to 200 miles due to the almost mandatory need for a fire solution and up-to-date for such long distances and such slow missiles.
