Semi active A-A missiles

[Ardillita]

Clarify me something please: a semi active radar is guided all the way to his target by the plane´s radar who lauched it.

 

So, if it is the plane´s radar who is guideing, and if this radar never loose its lock onto the target, why is the missile fooled by a chaff decoy? if the radar is always locked onto the target and never locks the chaff, why the missile can be fooled by the chaff decoy?

 

If the radar would loose his lock... that would be a different story, by my question is in the situation of never looseing look onto the target.

[D-Scythe]

Clarify me something please: a semi active radar is guided all the way to his target by the plane´s radar who lauched it.

 

So, if it is the plane´s radar who is guideing, and if this radar never loose its lock onto the target, why is the missile fooled by a chaff decoy? if the radar is always locked onto the target and never locks the chaff, why the missile can be fooled by the chaff decoy?

 

Cause the radar ISN'T guiding it. The missile guides itself. The radar just acts like a flashlight that lights up the target so the missile can see it. Doesn't mean that the missile won't be fooled by all the smoke/mirrors the target throws out to confuse it though.

[GGTharos]

Because the chaff reflects radar energy, and the missile's seeker sees it.

 

The missile is NOT guided by the launching aircraft's radar. The missile is guided to the REFLECTION of the launching aircraft radar's beam from the target, and has it's very own lock on that reflection.

[Ardillita]

ahaha

 

haha, perfect, thanks!

[D-Scythe]

Ha, beat you GG :p

[GGTharos]

#(*($* D-Scythe ;)

 

Darn that guy! ;)

[JaBoG32_Prinzartus]

Should a semi active radar A2A missile, then not guide actively to a jammer emitting target?

 

Because it would recieve the radar emissions of the jammer, though in different strenghts and different wavelengths, making the missile's interception course hard to estimate, but it should at least "see" in what direction the target is, even if it is not "enlighted" by radar.

 

Maybe there is still apossibility to get hit if the target does nottur of jammers...

 

Maybe this is implemented already, because I have noticed 27ER-missiles hit planes after I got shot. once or twice...

[Force_Feedback]

What if they could ake a missile with an accurate INS and gps-like system, and an acurate INS+gps-like system, then letting the missile be guided through radion commands, while the radar of the launcher tracks the target. the missile could be lighter, as no seekers are needed, allowing for a bigger warhead. Buy maybe it's not ECM-resistant.

[GGTharos]

You wouldn't hit anything ;) There's a reason why these things are equipped with seekers. It's ok to use gps-corrected INS against a non-moving target, but even then you have several meters of CEP.

[D-Scythe]

What if they could ake a missile with an accurate INS and gps-like system, and an acurate INS+gps-like system, then letting the missile be guided through radion commands, while the radar of the launcher tracks the target. the missile could be lighter, as no seekers are needed, allowing for a bigger warhead. Buy maybe it's not ECM-resistant.

 

Unless the missile has a small tactical nuclear warhead, such a weapon would be useless. At least with current technology.

 

Just think - a JDAM has a CEP of about 9 m against a stationary building. How big do you think the CEP is gonna get when the target is a 3 dimensional, supersonic moving target? It's just not feasible at the moment.

 

Because it would recieve the radar emissions of the jammer, though in different strenghts and different wavelengths, making the missile's interception course hard to estimate, but it should at least "see" in what direction the target is, even if it is not "enlighted" by radar.

 

Think of an SARH missile as an ARH missile. Their seekers are basically the same - it's just that a SARH missile cannot transmit its own radar emissions to track a target. However, the way they *basically* recieve radar waves bouncing off the target is the same - it's just that these radar waves simply came from a different source.

[Force_Feedback]

Guess I overestimated the current state of technology (that we know of), thought we had powerful computers and laser gyros, capable of calculating billions of floating point calculations per second. Oh well, they can at least make consoles for stoner meets (I suck at rolling blunts).

[tomcat1974]

man the JDAM has 10 m CEP accuracy by INS only . With the GPS aids it is under 3 m.

[GGTharos]

3m against a -non moving- target. Less accurate than an LGB in fact.

 

Not good enough for air to air work, at all.

 

Not to mention target coordinates are never updated ... while using your radar to track the target also imposes a significant CEP, and you need a rapid-update datalink to your weapon for it to actually track successfuly, meaning STT lock.

[D-Scythe]

man the JDAM has 10 m CEP accuracy by INS only . With the GPS aids it is under 3 m.

 

For what kind of target? Come on! You know the answer...these targets are big and on the ground and most importantly, NOT moving...well, at least not moving in 3-dimensions.

 

FYI, the 3 m CEP is only attainable AFTER an upgrade. Current JDAMs have the 9 m CEP, EDIT, nope apparently a 13 m CEP with GPS. Without GPS, CEP balloons to 30 m.

 

And before anyone says that JDAMs can hit moving ground targets, lemme just say that one, laser-guided bombs are still preferred, two, targets are moving only in two-dimensions, and three, JDAMs have a 500 lb, 1000 lb or 2000 lb warhead. Which makes it okay to miss a little.

[Alfa]

Clarify me something please: a semi active radar is guided all the way to his target by the plane´s radar who lauched it.

 

No at the initial stage of engagement, the aircraft radar is guiding the missile towards the target by transmitting "ready-made" guidance commands directly to the missile´s onboard navigation system. At terminal stage of engagement - i.e. at the point where the small antenna of the missile seeker can pick up the aircraft radar´s return signals(bouncing off the target), it will take over and generate its own guidance commands.

 

A semi-active radar seeker has, as the term indicates, sort of half a radar - it has a small antenna to pick up target return signals and a processing unit to turn them into guidance commands for its onboard navigation system, but it doesnt have an emitter to generate them in the first place.....hence the need for the aircraft radar to maintain lock and bombard the target with a radar pulse and thereby provide the return signals for the seeker to home on.

 

An active radar seeker, on the other hand, has a complete little radar with its own emitter and therefore no longer needs support from the launching aircraft by the time the missile reaches a point where the seeker can see the target by itself.

 

So, if it is the plane´s radar who is guideing, and if this radar never loose its lock onto the target, why is the missile fooled by a chaff decoy? if the radar is always locked onto the target and never locks the chaff, why the missile can be fooled by the chaff decoy?

 

Because when the missile seeker can see the target by itself, it "overrides" the guidance commands sent by the aircraft radar.....so if the seeker is fooled to believe that chaff is the target, it will steer the missile towards that.

 

The purpose of a missile seekerhead is to provide a target homing device in close proximity to the target - capable of reacting to target movement and thus update steering commands for the missile´s navigation system with the split-second reaction time necessary for the missile to intercept the target.....so the guidance commands generated by the seekerhead will take preference over those generated by the launching radar(in this case the aircraft radar).

 

Cheers,

- JJ.

[Sleek]

Because the chaff reflects radar energy, and the missile's seeker sees it.

 

The missile is NOT guided by the launching aircraft's radar. The missile is guided to the REFLECTION of the launching aircraft radar's beam from the target, and has it's very own lock on that reflection.

then why the hell do i allways get downed online in my old Hog lol :D

 

in fact don't answer this..coz i think i know what's comming hehe

 

EDIT: p.s i forgot to mention i release shiat loads of chaff flare after launch

[GGTharos]

... Yeah ;)

 

1. Drop Chaff and flares

2. Cuss out your top cover for not being there.

[D-Scythe]

then why the hell do i allways get downed online in my old Hog lol :D

 

in fact don't answer this..coz i think i know what's comming hehe

 

EDIT: p.s i forgot to mention i release shiat loads of chaff flare after launch

 

It also depends on where/when you release your decoys. If you absolutely have to evade a SAM, the best time to release decoys is when you're facing it or if it is directly behind you (not so IRL, but in LOMAC it is). Focus on dumping your decoys then.

[ARM505]

Just out of interests sake, (and for one day when LOMAC has it right ;) ), when is the best time to release chaff for defeating radar guided weapons?

[D-Scythe]

Read the post above ;)

 

Specifically, the answer to your question is head-on or tail-on, to the missile. Let me state that this is completely wrong for modern radar missiles.

[Kula66]

I remember a discussion ages ago where the idea was discussed. The concensus seemed to be get the chaff between you and the missile ... or as near as possible. So chaff dumped behind you is no good for a missile coming at you from head-on.

[GGTharos]

In addition to what D-Scythe said ...

 

Against Radar guided missiles, you want to dump decoys when they are are within 15km/7nm - that's when their seekers take over from the datalinks. Any time before this, and your chaff will simply be ignored.

 

Against IRH, you want to have flares out before they're even launched ... the possibility that tehy will lock onto a flare before launching is much greater than them locking onto a flare after they have locked on to YOU!

[D-Scythe]

I remember a discussion ages ago where the idea was discussed. The concensus seemed to be get the chaff between you and the missile ... or as near as possible. So chaff dumped behind you is no good for a missile coming at you from head-on.

 

Nope, new consensus. Idea now is to notch incoming missile and release chaff, so your aircraft can get lost in the clutter (i.e. chaff). Monopulse radar missiles like AMRAAM ignores stuff that don't really produce doppler (i.e. chaff). Thus the best way to fool an AMRAAM is to not produce doppler, by notching, thus disappearing into clutter (i.e. chaff) ;)

[GGTharos]

Actually Kula's also right, in the sense that you can hide in a chaff corridor ... unlike ground clutter, the chaff -can- get between you and and the seeker, which will down your return out even more (basically you're creating a gain/noise issue. You can fliter all you want, it really don't matter since your seeker is becoming saturated and the fliter is done -after- the reflection is received) ... so chaff corridors would still be useful.

 

HOwever! It's not likely, IMHO, that a single fighter can produce a useable chaff corridor. That's lef tto dedicated chaff drones used to mask bomber formations etc.

[nscode]

Read the post above ;)

 

Specifically, the answer to your question is head-on or tail-on, to the missile. Let me state that this is completely wrong for modern radar missiles.

 

He was asking what would it be IRL.