R-27EP

[Fri13]

What I have found is same that the R-27P can be launched totally passively by just using the missile own seeker, allowing to do stealthy surprise attacks without target knowing missile was launched at it, it cant be targeted via radar etc.

 

But as targeting system is classified...

[fixen]

I just found out that this missile existed today. I always wondered why there is no passive radar seeker on a air tot air missile. Searched for a topic on this missile on the forums.

 

Advantages:

No launch warning

No radar required

 

Disadvantages:

Can only be fired in head on engagements with the bandit being nose hot

If the bandit makes a turn or goes defensive the missile will lose lock.

 

I still think this missile would be quite effective with the disadvantages though.

Even if the reciever can't find the radiating bandit at long range you could guide it to target without him getting a launch warning. When we fire an aim-120 at a target in TWS it is also guided in the first stage without getting a launch warning right?

The missile only has to be guided in the general direction, that does not require an STT lock. Once the passive seeker is picking up radiation it can go "pitbull". This would mean it can not be targeted accuratly though. It would just head towards the first airborn radar emittor.

 

But all that aside, the passive seeker probably does have quite some detection range.

 

Maybe we will get more of these missiles in the future. When a fighter gets equiped with something like an ELINT pod used on the SU-25T but then for air to air use wich can determine the position of bandits relatively accurate, I could see it work. The missile could get radio guided in the first stage by info from the ELINT pod. Once the seeker sees the target itself it goes "pitbull".

[GGTharos]

Advantages:

No launch warning

No radar required

 

Neither of those is necessarily true.

 

Disadvantages:

Can only be fired in head on engagements with the bandit being nose hot

If the bandit makes a turn or goes defensive the missile will lose lock.

 

Also not necessarily true.

 

I still think this missile would be quite effective with the disadvantages though.

 

Which is exactly why everyone is building and equipping them! .... :) ... not.

 

Even if the reciever can't find the radiating bandit at long range you could guide it to target without him getting a launch warning. When we fire an aim-120 at a target in TWS it is also guided in the first stage without getting a launch warning right?

 

So? The AMRAAM platform is built to operate that way. The SU-27S is most certainly not built to operate that way. Later variants maybe ...

 

The missile only has to be guided in the general direction, that does not require an STT lock. Once the passive seeker is picking up radiation it can go "pitbull". This would mean it can not be targeted accuratly though. It would just head towards the first airborn radar emittor.

 

Can it even reliably target a radar that isn't in STT or similar mode?

 

Maybe we will get more of these missiles in the future. When a fighter gets equiped with something like an ELINT pod used on the SU-25T but then for air to air use wich can determine the position of bandits relatively accurate, I could see it work. The missile could get radio guided in the first stage by info from the ELINT pod. Once the seeker sees the target itself it goes "pitbull".

 

No, we won't. No one's making these types of missiles regardless of how much blah-blah has been written and spoken about it. All AAMs are pretty much (S)ARH or IRH, because they are most accurate.

 

Why do you want a radar-homing missile on your pylons instead of an active or a heater anyway? It gives you zero advantages over the others, and in fact it degrades combat capability since you can strictly use it against targets that are constantly radiating. It's even worse when those targets employ ECM/ECCM, the poor thing will get seriously confused.

[combatace]

Only disadvantage I see in this missile is that if you launch it on a pair of jets, and if the jets are flying close seeker will not know which jet to engage and can engage any one of them.

[fixen]

Neither of those is necessarily true.

Why do you want a radar-homing missile on your pylons instead of an active or a heater anyway? It gives you zero advantages over the others, and in fact it degrades combat capability since you can strictly use it against targets that are constantly radiating. It's even worse when those targets employ ECM/ECCM, the poor thing will get seriously confused.

 

First let me say that i am no expert at all. But i can still see advantages:

1. No radar required, thus no warning (depending on range ofcourse, outside MWS range)

2. Heaters have quite a range limitation due to the nature of the seeker

3. More and more aircraft are getting stealth capability's, if you can use the signal they are emitting you don't need to break their stealth.

 

Maybe we will never see them, maybe the technology just isn't refined enough and we will see them in the future. I just don't think you should discard it so easily.

[GGTharos]

First let me say that i am no expert at all. But i can still see advantages:

1. No radar required, thus no warning (depending on range ofcourse, outside MWS range)

 

Yes it is, if you want a long ranged shot. Otherwise you're pretty much stuck with 'revenge shooting' against a target in STT. Which is a luxury you just won't have any longer, since all your opponents are using ARH missiles (so they can turn away before your missile reaches them), and LPI radars (so your missile will probably not track them anyway). That's if they're using STT at all.

 

2. Heaters have quite a range limitation due to the nature of the seeker

So does everything else. Heaters are equipped with data-links for today for BVR/LOAL shots. Look up MICA-IR for example.

 

3. More and more aircraft are getting stealth capability's, if you can use the signal they are emitting you don't need to break their stealth.

No, you can't, because it's probably an LPI radar, and on top of that he might be sitting quite far away and feeding data-link data to his buddies who are sneaking up on you. More to the point, this wasn't even done in an era where your opponents HAD to be in STT for their missiles to hit you ... never mind what's going on now.

 

Maybe we will never see them, maybe the technology just isn't refined enough and we will see them in the future. I just don't think you should discard it so easily.

Why? The air forces of the world seem to have discarded them. There's always loads of blah-blah about them, but nothing useful.

[Robin_Hood]

Note that I am not defending the missile or the concept, or (God forbids) its addition to DCS, but I am curious.

 

Just from a theoretical standpoint, why would a passive radar ARM need its target to be in STT ? I fail to see why it couldn't be launched at a scanning radar (RWR gets a signal, why wouldn't the missile? Probably wouldn't be as efficient without a rock solid signal, though). Besides, wouldn't STT from the target radar risk that the missile simply gets out of the radar cone and thus lose its homing source (cause in STT the enemy radar is centered on your aircraft). Actually, come to think of it, it seems in any case there may be a rather good chance for the missile to find itself out of the radar cone and in the dark.

 

By the way, I noticed that the website provided also mentions the following (in addition to what has been quoted earlier, and ignoring the typo for IR):

 

The R-27P1 and R-27EP1 unified medium-range air-to-air missiles with passive IR homing heads are designed to engage radio-emitting air targets by day and night, in fair and adverse weather conditions, in the front hemisphere, also against diverse underlying bachgounds and in cases when the enemy targets protect their aircraft with anti-radar active jamming.

It almost sounds like this is more of a specialized Home On Jam missile rather than a passive radar-homing (unless of course the website is once again unreliable). Would be even worse in todays environment in that case, I believe. Edited June 16, 2015 by Robin_Hood

[King_Hrothgar]

Any EM emission can be detected and tracked. There is no way even on a theoretical level to change this. As such, a missile that homes on a target's own EM emissions is possible. There are some practical concerns of course, but an air to air version of a HARM could certainly be done if one were so inclined. The type of radar the target aircraft uses is completely irrelevant. It can always be detected and tracked if it is emitting. The same is true of communications radios, datalinks and anything else that is actively emitting EM radiation. Additionally, approximate range information can be acquired via triangulation. Though not nearly as accurate as other methods, it is completely jam proof. In fact, attempting to jam someone doing this would only make their job easier, as it increases the signal strength.

 

I'm not making any claims on how practical such an air to air missile would be. Anti-radiation missiles work fine against slow moving or stationary surface radars. But trying to hit a jet fighter going 1000km/h or more would be much more difficult.

[Avimimus]

Any EM emission can be detected and tracked. There is no way even on a theoretical level to change this. As such, a missile that homes on a target's own EM emissions is possible. There are some practical concerns of course, but an air to air version of a HARM could certainly be done if one were so inclined. The type of radar the target aircraft uses is completely irrelevant. It can always be detected and tracked if it is emitting. The same is true of communications radios, datalinks and anything else that is actively emitting EM radiation. Additionally, approximate range information can be acquired via triangulation. Though not nearly as accurate as other methods, it is completely jam proof. In fact, attempting to jam someone doing this would only make their job easier, as it increases the signal strength.

 

I'm not making any claims on how practical such an air to air missile would be. Anti-radiation missiles work fine against slow moving or stationary surface radars. But trying to hit a jet fighter going 1000km/h or more would be much more difficult.

 

Not entirely, if the radar emission is turned off intermittently, or is highly directional, and changes its direction periodically... the missile would lose track.

 

IMHO, such a missile would work well as a deterrent against keeping a jammer on continuously. *If* it worked, it could have a tactical role (other than shooting down the target).

[fixen]

Any EM emission can be detected and tracked. There is no way even on a theoretical level to change this. As such, a missile that homes on a target's own EM emissions is possible. There are some practical concerns of course, but an air to air version of a HARM could certainly be done if one were so inclined. The type of radar the target aircraft uses is completely irrelevant. It can always be detected and tracked if it is emitting. The same is true of communications radios, datalinks and anything else that is actively emitting EM radiation. Additionally, approximate range information can be acquired via triangulation. Though not nearly as accurate as other methods, it is completely jam proof. In fact, attempting to jam someone doing this would only make their job easier, as it increases the signal strength.

 

I'm not making any claims on how practical such an air to air missile would be. Anti-radiation missiles work fine against slow moving or stationary surface radars. But trying to hit a jet fighter going 1000km/h or more would be much more difficult.

 

This... you can simply track the emisions of the radar and get an aproximate position.

I can see problems with accuracy because of the fast movement of jets though.

This is where 2 forms of tracking would be required (wich is as metioned in this topic is not really done yet). Final stage could be IR tracking to get the high accuracy required for a hit. This way it would still be a silent yet long range missile. RWR can recieve radar signals before they have a chance to lock you up. Then you just have to shoot a missile in that direction and when in range the missile switches to IR mode.

 

By the way, i was not suggesting this missile to be added to the SU-27. Just liked the idea of the missile.

 

Not entirely, if the radar emission is turned off intermittently, or is highly directional, and changes its direction periodically... the missile would lose track.

 

IMHO, such a missile would work well as a deterrent against keeping a jammer on continuously. *If* it worked, it could have a tactical role (other than shooting down the target).

 

That could indeed be a problem. What if the missile just keeps going in the expected position of the aircraft (the enemys path and speed is known afterall) until it gets an update again of the enemy's radar. This would not work against highly manouvering targets ofcourse. Final stage of the missile in IR mode and the enemys radar is not needed anymore.

 

Edit:

I have been reading about the LPI radar. That would indeed complicate things.

Edited June 16, 2015 by fixen

[King_Hrothgar]

Not entirely, if the radar emission is turned off intermittently, or is highly directional, and changes its direction periodically... the missile would lose track.

 

IMHO, such a missile would work well as a deterrent against keeping a jammer on continuously. *If* it worked, it could have a tactical role (other than shooting down the target).

 

That's why I stated very clearly and repeatedly that it only works if they are actively emitting. From a practical standpoint, the obvious way to go about it would be to use anti-radiation until IR or ARH lock.

[Alfa]

 

.. It almost sounds like this is more of a specialized Home On Jam missile rather than a passive radar-homing

 

Well it definately has a passive-radar homing head, but you may be right about it having been intended as a specialised "home-on-jam" weapon in supplement to the SARH version for situations where this is less effective/cant be used - i.e. in much the same way as with the -ET.

[GGTharos]

Just from a theoretical standpoint, why would a passive radar ARM need its target to be in STT ? I fail to see why it couldn't be launched at a scanning radar (RWR gets a signal, why wouldn't the missile? Probably wouldn't be as efficient without a rock solid signal, though).

 

Because you want to hit the target. More specifically, STT gives you a constant radiation source, so you can constantly update the flight trajectory like a heat seeker.

 

I would guess that a scanning radar will increase the missile's miss distance, and if you really think about it, it only needs to miss by about as much as your wingspan. Even if you're not maneuvering, and your antenna is coming around as fast as every 2 sec (APG-63 in TWS mode), you're still correcting once every 2 sec WITHOUT feedback after the correction as opposed to say ever 1/20th of a second. So now you have to deal with seeker settling times and INU drift.

 

Besides, wouldn't STT from the target radar risk that the missile simply gets out of the radar cone and thus lose its homing source (cause in STT the enemy radar is centered on your aircraft). Actually, come to think of it, it seems in any case there may be a rather good chance for the missile to find itself out of the radar cone and in the dark.

 

Depends on the target radar. Most have significant sidelobes. Some very modern radars ... don't. :)

 

It almost sounds like this is more of a specialized Home On Jam missile rather than a passive radar-homing (unless of course the website is once again unreliable). Would be even worse in todays environment in that case, I believe.

 

Yep, it could work nicely to attack some sort of noise jammer. :) SAMs certainly employ their missiles with such capability in mind, though SAMs also tend to do slightly more complicated things.

[GGTharos]

In that case you'd be shooting a SARH and ARM ... you may as well shoot SARH and IRH, your payload is overall more effective.

 

At least that's my opinion after seeing how some of this jamming works - and with ecm+chaff these days, not to mention towed decoys, ARMs probably become next to useless.

 

Well it definately has a passive-radar homing head, but you may be right about it having been intended as a specialised "home-on-jam" weapon in supplement to the SARH version for situations where this is less effective/cant be used - i.e. in much the same way as with the -ET.

[Weta43]

I can't see that there's a need for a dedicated (edit - to be clear - medium range) PARH missile - for a searching BVR radar to be able to detect a relatively small RCS target the signal at the target is orders of magnitude greater in strength than the return signal at the emitter, the seeker in any ARH or a SARH MRAAM is going to be capable of detecting the output of the searching radar while still well into what would be considered 'BVR', provided it has the processing power and software to find the signal - it's essentially only the same trick as using the SARH /ARH head to do HOJ.. (the frequency is in the same ball park as the reciever on the missile is designed to recieve, all you need is processing power, and processing power is cheap, light and doesn't use as much battery as an ARH head.)

To the best of my knowledge you don't neeed an M-link to fire HOJ - the missile just flies a dumb course at the emitter on a trajectory based on range (which you could get through simple triangulation from a couple of data-linked aircraft) set at launch - IR missile missiles do it without range data...

That means no launch warning, and no reason to turn off the emitter (particularly as ignoring Hz jumping etc - just plain physics says you can see the radar before the radar can see you).

If the target were to turn off its radar or turn away, you could then revert to a more conventional guidance system - STT / datalink / ARHTG...

 

As an asside - the US did try the concept using a modified AIM-7 & it seemed to work against fighter sized targets..

 

"The first test firing of the Brazo missile was conducted in April 1974, with the missile, launched from a USAF F-4D Phantom II, successfully shooting down a BQM-34 Firebee drone; four follow-up tests over the following year continued the missile's successful record, with none of the test shots failing despite difficult test conditions"

Edited June 17, 2015 by Weta43

[GGTharos]

Why not quote the rest of the article that points out that all attempts at making such a missile were cancelled in the end?

 

And that's the point.

[Alfa]

In that case you'd be shooting a SARH and ARM ... you may as well shoot SARH and IRH, your payload is overall more effective.

 

No I meant "supplement to the SARH version" as in shooting an ARM instead of a SARH in some conditions(when the radar is being jammed) in the same way as picking an IRH for a receedig target instead of a SARH :) .

 

Personally I think the claim that it was standard procedure to launch a SARH followed immedeatly after by an IRH for increased PK is nonsense - the performance characteristics of SARH and IRH seekers are virtually reversed, so its a little difficult to see a situation where that would work and I suspect the idea might stem from the earlier false assumption that the R-27T/-ET has INS/radio correction.

 

At least that's my opinion after seeing how some of this jamming works - and with ecm+chaff these days, not to mention towed decoys, ARMs probably become next to useless.

 

Possibly, but then the -EP version isn't a new entity - we just haven't heard about it until recently.

[GGTharos]

I think it's the same case as elsewhere: It has been thought of, possibly tested/evaluated and then left behind.

 

Some modern concepts were trying to create a sort of AMRAAM/HARM hybrid from a functionality perspective, but that missile also got cancelled.

[Alfa]

Why not quote the rest of the article that points out that all attempts at making such a missile were cancelled in the end?

 

And that's the point.

 

Well there could be other reasons than performance issues for that - such as carrying specialised AAM versions for particular purposes making payloads less mission versatile.

 

As I see it, with the development of the AMRAAM the US instead went the "multirole" route with a single weapon for all types of BVR engagements.

[GGTharos]

Yep, I know. That's one reason why there's no reason to have such a weapon at this time.

[Svend_Dellepude]

Personally I think the claim that it was standard procedure to launch a SARH followed immedeatly after by an IRH for increased PK is nonsense - the performance characteristics of SARH and IRH seekers are virtually reversed, so its a little difficult to see a situation where that would work and I suspect the idea might stem from the earlier false assumption that the R-27T/-ET has INS/radio correction.

 

Could be from the early days of MiG-21 and -23 when missiles had shorter legs and ranges of SARH and IRH didn't differ that much.

[Weta43]

Why not quote the rest of the article that points out that all attempts at making such a missile were cancelled in the end?

 

Because I didn't think it added anything to the discussion.

 

We've all agreed that there's little call for a dedicated PR MRAAM, but I thought it was worth noting that as a weapon type, the US have demonstrated that they can be effective (even with 70's technology).

 

That said, as a dedicated weapon there are more useful things to carry, & with better processing power modern MRAAMs would probably be capable of performing this function at some level anyway.