[WAD + IMPR v1.11] Offensive Jammers Against ASM

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MBot
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[WAD + IMPR v1.11] Offensive Jammers Against ASM

Post by MBot »

What exactly is the application of ship-borne jammers? While the ASM's radar can be jammed, it can apparently track targets none the less.

The screenshot below, two AS-4 are attacking a container ship (under EMCON). A Virginia CGN behind is jamming with OECM. Both ASM are marked as being jammed, yet they track all the way to impact on the container ship (which is not home on jam, since the target is not jamming). Is this supposed to work like this?

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ComDev
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RE: Offensive Jammers Against ASM

Post by ComDev »

I don't remember if the missiles are HOJ capable but that's likely it.
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MBot
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RE: Offensive Jammers Against ASM

Post by MBot »

Yes, but the missile is striking its intended target at the right, a container ship, and not the jamming ship on the left. So radar guidance of the ASM seems to be unaffected despite being labeled as "jammed".
ExNusquam
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RE: Offensive Jammers Against ASM

Post by ExNusquam »

The effect of the OECM is to reduce the effectiveness of the radar. This usually means that the ASMs won't acquire a target until much closer. If the ships are moving, this can mean that the ships may be out side of the ASMs radar search area by the time they're close enough to acquire.

In the case you posted, the ships aren't moving, which means that at burn through, the ship will be exactly where the missile expects it to be.
Dimitris
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RE: Offensive Jammers Against ASM

Post by Dimitris »

"Jammed" does not automatically equate to "blinded". The only way to be absolutely certain you are indeed overwhelming the other guy's radar is to sail/fly right past him and have him fail to take a shot at you that he would otherwise take.

(And even then, it may be that he's just reloading...)
ComDev
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RE: Offensive Jammers Against ASM

Post by ComDev »

Hmmm and we also take main beam and sidelobes into account when calculating the thermal effects that the RF noise has on the antenna.

Can you upload a savegame?
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MBot
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RE: Offensive Jammers Against ASM

Post by MBot »

Here is a test scenario. Thanks for having a look.

I think the stationary nature of the ships plays no role. In the editor you can move the target ship around and the ASM will immediately track it despite being jammed. What I would have expected is that the ASM change to HOJ and attack the jammer instead.
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kneecaps
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RE: Offensive Jammers Against ASM

Post by kneecaps »

It's not an all or nothing situation. The usual situation is that a 'burn through' will eventually occur...

Also a container ship is going to have a massive radar return, the container ship is also nearer the missile that the jammer, so you have all kinds of inverse square stuff going on...

The AS-4 has about a 50-60 NM radar range if I recall...so at the distances possibly shown there is going to be significant radar energy coming back from the container ship also...I'd expect jamming to be almost useless in this situation..
MBot
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RE: Offensive Jammers Against ASM

Post by MBot »

ORIGINAL: kneecaps

It's not an all or nothing situation. The usual situation is that a 'burn through' will eventually occur...

Also a container ship is going to have a massive radar return, the container ship is also nearer the missile that the jammer, so you have all kinds of inverse square stuff going on...

The AS-4 has about a 50-60 NM radar range if I recall...so at the distances possibly shown there is going to be significant radar energy coming back from the container ship also...I'd expect jamming to be almost useless in this situation..

The situation can also be reproduced with a small fishing boat, AGM-84A with a small radar seeker and shorter distances between jammer and target. So far I could not find a situation where OECM has an influence whatsoever on ASM.
Luidzi
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RE: Offensive Jammers Against ASM

Post by Luidzi »

I've tried switching the container ship with a stealth ship, like Visby or Skjold, and tried different positions. I used BoA launch, so the missile is purely self-guided without any assistance from the aircraft.
Once missile starts homing at a particular target, it will never change targets unless the first one disappears from its FOV (is completely destroyed). However, I've found some strange behavior - the closest target will be always locked first, at maximum range (80nm), no matter if it's a cruiser, or a stealth corvette, or a life boat, even if the seeker is jammed. It seemed to me like the seeker of AS-4 completely ignored both jamming and target signature.
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RE: Offensive Jammers Against ASM

Post by ComDev »

Thanks guys [8D]

Re: the stealth corvettes and smaller boats, we fixed signatures and adjusted the clutter model for 1.09. Would recommend you switch to that version and also rebuild the scenarios with version 440 of the database.
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RE: Offensive Jammers Against ASM

Post by wild_Willie2 »

"So far I could not find a situation where OECM has an influence whatsoever on ASM"

I quickly ran a test scenario to test your statement using a DD1000 as a target verses several generations of SSN missiles and after five minutes I already have four SSN-2c's flying over the jamming target while all four hit the same target while it was not jamming.
* SSN-12 radars could detect the jamming target via radar, but could also have detected and hit it using it's IR sensor.
* SSN-19 radars could detect and hit a jamming target when I selecting the jamming target (all four missiles), but when I did a bearing only launch straight at the jamming target all 30 missiles missed while they should HOJ (This is weird and probably a bug??)
* SSN-22 radar could detect and hit a jamming target when I selecting the jamming target (all six missiles), and when I did a bearing only launch straight at the jamming target all missiles hit.
* SSN-3 radar could detect and hit a jamming target when I selecting the jamming target (all six missiles), but when I did a bearing only launch straight at the jamming target all 20 missiles missed while they should HOJ (This is weird and probably a bug??)

So while I could detect a significant effect of jamming on the SSN-2c's, no effect could be detected on the other SSN so you might be right, HOWEVER I did find a bug in the BOL launch functionality of both the SSN-3 and SSN-19 missiles. These will miss 100% of the time when in BOL mode against a jamming DD1000 and this is inconsistent with the results of the same missiles fired via manual launch at the same target.

I will upload a test scenario of this bug in the tech support section.
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magi
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RE: Offensive Jammers Against ASM

Post by magi »

This is interesting... For sure....
ComDev
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RE: Offensive Jammers Against ASM

Post by ComDev »

Answered here:
tm.asp?m=3939380

Thanks guys [:D]
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