SAM "home on jam" ?

Hello everybody,

Sorry if this subject has been previously answered but I was wondering what are the risks to use the jammer pod all the time. I guess it's possible for a more or less recent SAM system to home on the active jamming device. My questions are:

-IF ANY, wich SAM systems can do that?

-will turning jammer off for some time (how much?) make the missile loose it's target for a moment or will it simply immediatly switch to another tracking mode?

Thanks for your help.

NeFFertitties.

Quick google search yielded this study: APA-Engagement-Fire-Control.

For the SA-6 it states: "A Home-On-Jam (HOJ) capability is cited by Russian sources".

In principle, while jamming the enemy radar has only angular information (bearing and elevation). You throw off any distance and velocity measurement. That is until burn through occurs (this is the point at which the radar is able to filter out its own return signal from the jamming noise you are producing).

Because the enemy can only indirectly estimate your position, they have to guess whether you are in their engagement envelope or not. Plus fire control of the missile in flight cannot use an optimal trajectory because your velocity is unknown. Basically, the missile can use proportional navigation, which requires only angular information, but against a maneuvering target the trajectory will be quite sub optimal. Finally, time to go is unknown. This is one of the most important variables in missile guidance control. These factors add up to the fact that HOJ has a much lower PK (probability of kill).

I don't know to which degree this is present in DCS. At least some AA missiles have HOJ capability and exhibit some degraded performance, so it might be modelled for SAM as well.

EDIT:

From the same site (APA-Legacy-SAM-Upgrades):

Technical Note #4 Anti-Radiation Seekers for SAM Upgrades

 

Avtomatika L-112E anti-radiation seeker. This family of seekers employs a characteristic gimballed multiple baseline interferometer design which uses a cluster of seven wideband hemispherical spiral antennas, providing for pitch/yaw steering outputs and ambiguity resolution in both axes. The design is a credible candidate for larger SAM airframes such as the 48N6E series and 5V28 series (© 2009 Vitaliy V. Kuzmin).

 

The installation of anti-radiation seekers in SAM airframes is not a new idea. The PLA's FT-2000 anti-radiation SAM was built with a wideband anti-radiation seeker. Narrowband Home-On-Jam (HOJ) capability has been installed in a range of semi-active and active homing radar missile seekers, primarily intended to discourage active jamming of the missile seeker. The MIM-104B ASOJ Patriot variant is credited with such a capability.

 

There are no open source reports of dedicated anti-radiation seekers being installed in recent Russian SAM designs. A narrowband passive anti-radiation capability is likely in more recent semi-active and TVM capable seekers, as this capability exists in supersonic anti-shipping missile active radar seekers of similar size.

 

There are no fundamental technical obstacles to the retrofit of a wideband anti-radiation seeker to larger Russian SAM airframes, such as the 48N6, 9M82, 9M83 or legacy 5V28. Existing seekers such as the Avtomatika L-111E/112E/113E series used in subtypes of the Kh-31 / AS-17 Krypton anti-radiation missile are geometrically and volumetrically compatible with these SAM airframes. Guidance adaptations would not be particularly challenging where the missile employs midcourse command link / inertial guidance, the principal aim being to fly the missile into a viable acquisition basket for the seeker, and cue the seeker to acquire the intended emitter. Modern anti-radiation missile seekers are usually capable of autonomous target acquisition, or re-acquisition should an emitter go silent transiently.

 

The technology is certainly available to inexpensively equip any number of recent Russian SAM airframes with anti-radiation seekers. Passive targeting capability via emitter locating systems such as the 85V6 Vega / Orion or Kvant 1L222 Avtobaza presents no difficulty, both designs have been integrated with the S-400 / SA-21 fire control system. The CONOPS for such a system would involved passive angle tracking and ranging on an emitter, with the SAM round flown out under command link control to a geometrically optimal position, upon which the anti-radiation seeker would acquire the target and terminal homing would be performed. Existing control laws for terminal homing in HOJ modes would be viable.

 

Until terminal homing is initiated, a defending aircraft will have no easy means of determining whether an inbound SAM is fitted with an anti-radiation seeker. This will complicate defensive countermeasures scheduling and defensive tactics. A salvo of two SAMs, one with an anti-radiation seeker, and one with an active or semi-active homing seeker, will present similar difficulties to those seen with the use of mixed seeker types in Beyond Visual Range (BVR) AAM attacks.

Seems like I had some reasons to worry then! Can someone tell us how this is modelled for DCS SAM systems?

i love the fact that some of the testing i did recently in DCS world has proved that not all SAMs are stupid.. i put some tunguska's in between the block in city..so they were hidden.. and after A-10 shoot maverics and failed and tried bombs and failed i saw the Tunguska respond by repositioning itself to a safer location or at least away from previous location.. still it doesn't do the best optimal move but at least it moves when under fire)) ..

about SAM's in general..yeah much more needed to simulate them..

From what i understand, ECM effects are barely modeled, if at all. For the longest time, the -131 on the A-10 didn't do anything other than look pretty. I don't know if that has changed, i haven't tested it much. I still do a couple flashes before beaming for an incoming SAM, but i think that's more of a good-faith gesture than anything else..lol.

In regards to leaving an ECM pod on all the time, there are many drawbacks to doing so. The biggest one, is the fact that you broadcast your presence to anyone in the area with an air search radar.

Radar systems can pick up a transmitting ECM pod farther out than they can see an actual aircraft. They might not be able to track you specifically, but they definitely know you are there.

Radars all have a 'burn-through' range as well(distance varies by radar type), which means that inside a certain distance, the radar is able to over-power your ECM and lock you anyway.

So, by leaving your ECM on all the time, all you are doing is broadcasting your position to any nearby enemy units who then just have to relay that info to the closest fighter. He will then close on your position very quickly, get to burn-through range, and give you a nice missile to the face. Or, if he's carrying some HOJ equipment, you'll be dead even faster because he doesn't have to close with you as much.

Best practice for the ECM is to leave it off until you really need it. If you get launched at by a SAM:

1)Flash the ECM a couple times (on/off/on/off in quick succession) while dropping chaff

2)Turn to put the missile (or SAM site if you can't see the missile) on the beam (your 3/9 line)

3)Wait until you can see the missile is actually a missile and then slice hard into it while dropping a couple more packs of chaff.

4)Pray ;)

Remember, the -131 only works in arcs in front of, and behind, the aircraft. It doesn't do anything to the sides. So there's no point in having it on unless the locking radar is directly in front of, or behind, you anyway.

Has anyone done any significant testing with ECM's in DCS lately? Does it work any better than it used to or is it still, pretty much, non-existant?

It's modeled by your jammer not really doing anything - in other words, right now there isn't much to electronic warfare. It might be expanded some time in the future :)

Seems like I had some reasons to worry then! Can someone tell us how this is modelled for DCS SAM systems?

Most jammers carrier by fighters are deception jammers. Their representation in-game is incorrect since they don't carry channel and bandwidth information, so those jammers jam 'everyone' (if everyone is a player) in all modes, like a noise jammer.

What they should do is break STT track on radars that are targeting them, and even then they can deal with a limited number of radars at the same time (which is why they wouldn't be jamming radars in search mode).

Remember, the -131 only works in arcs in front of, and behind, the aircraft. It doesn't do anything to the sides. So there's no point in having it on unless the locking radar is directly in front of, or behind, you anyway.

I don't quite understand what you are replying to in the quote there but i was under the assumption that it was capable of doing both. Either, generating a type of 'noise' blanket or using a RGPO type STT deny.

Now, granted, i didn't do any work with the -131's when i was in the service so all that might just be hearsay i picked up over the years...lol.

OK so if I understand well, I have a useless an/alq-131 that I shouldn't turn on and there are no HOJ sams? (not bitching, just asking :))

OK so if I understand well, I have a useless an/alq-131 that I shouldn't turn on and there are no HOJ sams? (not bitching, just asking :))

You got it.

Well, thank you all for the info. :thumbup:

Yup, this goes for the Frogfoot as well, they are useless right now, except if you want to jam air targets, then yes, but against SAMs, no.

OK so if I understand well, I have a useless an/alq-131 that I shouldn't turn on and there are no HOJ sams? (not bitching, just asking :))

I cannot quite agree with that. You can use your jammer to extend your range into the radar's threat zone without getting locked. That's pretty much it, but it's not "useless". As far as HOJ goes I don't know about SAMs, but in the old FC the F15 could home its AIM120 on jam. But I don't know the status on that in the current FC3.

jammer in DCS merely gives false range, and should burn through if you're very close to SAM, becoming ineffective with reduced range. at least that is what I believe how it works in DCS.

I cannot quite agree with that. You can use your jammer to extend your range into the radar's threat zone without getting locked. That's pretty much it, but it's not "useless". As far as HOJ goes I don't know about SAMs, but in the old FC the F15 could home its AIM120 on jam. But I don't know the status on that in the current FC3.

You're wrong Donglr IF you are referring to SAMs. Jammers work-ish on air targets though at a distance, till you burn through it.

I have tested it out. ED testers have CONFIRMED this with me.

Jammers DO ABSOLUTELY NOTHING IN DCS AS OF RIGHT NOW against every single SAM in DCS, short/medium/long. They are a paper weight and a waste of precious ammo space on your A-10.

Jammes (currently) DO NOT let you:

-Get closer to the SAM

-Avoid lock for longer from SAM

-Shorten firing range of SAM

-Break lock of incoming missile from SAM

HOWEVER!!!!

Flying "Below" radar DOES get you closer to a medium to long range SAM. I have been able to get VERY close to a SA-10 range, and attack ships with long range defense missiles by flying BELOW 30 meters. Though in reality you have to be below 20 meters in the game. 14-17 meters is a successful height. Any higher than that and there are no guarantees at all.

You're wrong Donglr IF you are referring to SAMs. Jammers work-ish on air targets though at a distance, till you burn through it.

 

 

I have tested it out. ED testers have CONFIRMED this with me.

 

 

Jammers DO ABSOLUTELY NOTHING IN DCS AS OF RIGHT NOW against every single SAM in DCS, short/medium/long. They are a paper weight and a waste of precious ammo space on your A-10.

 

 

Jammes (currently) DO NOT let you:

 

-Get closer to the SAM

-Avoid lock for longer from SAM

-Shorten firing range of SAM

-Break lock of incoming missile from SAM

 

Hmm, I must admit you are right. I tested it just now in a clean environment, just me and a Tunguska. I could indeed not break the lock with the jammer. It is indeed useless against SAMs.

Which is strange, because contrary to popular belief, I'm not a mean ass bastard who want to screw you, but I remember a flight where I said to myself "I never used the jammer, I'll try it this time". And I'm pretty sure that the locking tone from a Tunguska was gone after switching on the jammer. I saved that event in my memory under "jammer can extend range into SAM threat zone". But now I'm not sure what really happened back then.

Anyways, I'm really considering not carrying a jamming pod around anymore. Jamming not being modelled for ground attacks really is a blowback in my optinion for this sim.