Forum: General F-35 Forum

ESM = Electronic Support Measures = Another word for RwR, EW (Electronic Warfare) equipment, etc.

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delvo wrote:

maus92 wrote:

Depending on the platform and the munition, an ASM could be launched without a precise location. The munition flies a search pattern, and then uses its on board sensor(s) to find a target.

That only helps if you know there's a target somewhere out there to find, or don't mind wasting missiles by using them merely as probes that get launched to search for something that turns out not to be there. The former gives no inherent advantage to either the ship or the plane, because our hypothetical scenario has to start by positing which one does or doesn't know that the other is somewhere around in the first place. The latter would be slightly less ridiculous for the ship because it can carry more missiles and thus can afford to lose/waste more, and because a single hit would probably be enough to destroy the plane.

The aircraft's ESM fit detects a hostile emission and provides a bearing and a rough range. Depending on the sophistication of both the platform and the munition, the attacking aircraft can launch an ASM without knowing the precise location of the target. The munition does its own terminal targeting.

and gets blown away by CWIS

Which is why we are designing more advanced ASMs with low levels of RCS in mind. The JASSM and JSOW both have LO features already.

I don't know how effective CIWS are anyway. Can LRASM-B or LRASM-A be air-launched? Those might be useful against a modern ship defense system assuming they enter service.

SpudmanWP wrote:

ESM = Electronic Support Measures = Another word for RwR, EW (Electronic Warfare) equipment, etc.

So what part of that group of equipment are we talking about detecting a stealth ship? What is emitted from the ship that the plane will detect? (And what would prevent the ship from picking up similar emissions from the plane, although size is an easy answer there)

Are we talking about electromagnetic radiation in a frequency not already covered by radar, electro-optical systems, and IR? What would that be? Microwave? UV? An otherwise unused band of radar/radio? Could it be a glitch in the local magnetic field? (I haven't heard of that being used to detect things from such a distance or heard that F-35s have such sensors, but if it could, that would be in a plane's favor, with less mass to detect and more of it being things like carbon fibers and composites.) Physically, there has to be SOMETHING going from the ship to the plane in order for the plane to detect the ship. What is it, in the case of detection by ESM?

sprstdlyscottsmn wrote:

and gets blown away by CWIS

...which is why the latest anti-ship weapons are stealthy and can maneuver... which is why the latest defenses get developed with improvements in their ability to detect and track things that don't want to be detected and tracked... which is why a serious attack on a ship would need to involve not simply the most advanced missiles/bombs but also large numbers of them, in the hope of overwhelming the defenses with just too many to catch all of. Any fighter can only carry a handful of anti-ship weapons, so they'd probably all get stopped, whereas it's easy for a ship to carry more than enough firepower to destroy a single fighter (if it can track it). Just firing several anti-aircraft missiles in sequence means that a successful maneuver to avoid the first would be timed wrong for the second. So the firepower imbalance alone might make the question of which one detects the other first irrelevant in real life; being detected means destruction for one, while for the other it just means having to fire some guns for a few seconds. The only way to give both sides the same stakes is to change the question so that it's a group of multiple fighters, each of them armed with as many anti-ship weapons as they can carry and spread out pretty wide so the weapons would approach the ship from various angles. And that's not a scenario that would happen unless the mission they were flying had been planned from the start as a ship-hunting mission.

There are three main sources of EM that the F-35's ESM gear (called the AN/ASQ-239 'Barracuda') will home in on. These are the ship's radar, the ship's comms, and leaky electronics on board the ship.

SpudmanWP wrote:

There are three main sources of EM that the F-35's ESM gear (called the AN/ASQ-239 'Barracuda') will home in on. These are the ship's radar, the ship's comms, and leaky electronics on board the ship.

And cabling...

Covered under "leaky" Wink

It would be interesting to see how an LRASM-B's maneuverability can screw up a Phalanx's gun lead solution considering its flight profile.

High speed maneuvering ASMs is one of the reasons that you see US ships transitioning to a SeaRAM type solution.

Fight a maneuvering missile with a maneuvering missile.

http://www.raytheon.com/capabilities/products/searam/

SpudmanWP wrote:

There are three main sources of EM that the F-35's ESM gear (called the AN/ASQ-239 'Barracuda') will home in on. These are the ship's radar...

It seems like a ship called a "stealth" ship would have to have some way of handling that already, like F-22's & F-35's "LPI" features. If not, why not, and what's the point of a stealthy structure & skin if using the radar gives it away? That's like wearing camouflage and a set of the brightest lights you can carry. And does a ship's radar normally run all the time, and would the same still be true of what was supposed to be a stealth ship with a non-LPI radar? (F-117 flew in radar silence for this reason; LPI radar hadn't been invented yet.)

SpudmanWP wrote:

...the ship's comms...

I'll have to treat this as meaning its communications with the outside world; internal communications between parts of the same ship, I'll group with the other things below.

It seems like it should be much easier for a ship to maintain communications silence than radar silence, except for brief check-in periods every few days that wouldn't be long enough enough to track it by or predictable enough to count on observing at all, and maybe not even that if it was sailing under hot conditions where it could expect airwaves to be monitored. If they don't/wouldn't, why not? What is there that a ship needs to keep constantly informing the outside world of, even when it's in airspace that the enemy flies?

SpudmanWP wrote:

...and leaky electronics on board the ship.

maus92 wrote:

And cabling...

OK, and these emit what? Waves in the radio frequency range? I'm thinking of the static a TV/radio can get depending on how close another electrogadget is to it and in what direction. I've never heard of that having any effect for dozens of miles away instead of just a few feet, or maybe a few dozen yards if you drive your car by one of those huge towers that hold lots of power cables up. I suppose detecting it from so far could be a matter of having specialized sensors that focus on picking it up on purpose, and the empty background of an ocean helps, but I still don't get why it wouldn't be absorbed by the radar-absorbing ship's skin.

...unless you're talking about emissions in some other frequency range that I didn't know electorgadgets emitted in.

A truely stealth ship is a submarine?

Ships of the sort I posted in the OP use LPI radars. The domestic European ship radars appear to be more advanced than their aviation radars, being AESA.

Forum: General F-35 Forum

F-35 and stealth destroyers?