AIM-7M sparrow & the RWR
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IRL again : selectivity, measurements accurancy, signal processing. In the lribray, if the signal carateristics are “too narrow” (to avoid ambiguities) it is possible that the measured signal doesn’t match the radar spec/missile link signal enough to trigger the Launch alarme (which is not always an evidence of launch, but, depending on missile type, could be only a, a/c radar precific signal/rate/freq/PRI … For a given missile type and launch plateforme, it is possible that the Launch alarm will be trrigered in one case, and not in the other.
fine, but you’re telling me that the act of pulling a split -S will disturb these criteria?
theorycraft: an F-4E is on your tail and fires a sparrow at you. your RWR notices an increase in activity and matches the radar’s activity state and precision and angle and intensity etc to it’s profile that determines “this is what an F-4E launching at you looks like” it warns you by flashing some lights etc, saying counter et cetera. this “activity state” (a measure of radar intensity, estimated range, precision, refresh rate, etc etc.) does not change after you pull your split S.
after the split S, the intensity state is exactly the same at the same range, of course more intense if closer, and less intense if further. but if you were at the same range, it would be exactly the same.
would it scream warning in both cases, logically as it uses the same criteria? if your RWR senses an incoming launch state it should warn you in both cases. just because the missile host is “temporarily in your blind spot” should not mean anything, should it? once you pull out of sensor occlusion the enemy radar activity should register as a launch state. the incoming activity is the same, and the RWR criteria is the same. is this not the case?
in the ideal world, it would be possible to be fired upon without a launch warning. so in the example being fired upon from behind with no sensor occlusion your RWR could fail to detect a launch state. and then if you do pull a split S then your RWR can still fail to warn you, but not BECAUSE of the maneuver (unless you stay in the ‘blind spot’ until the missile hits you) but because the RWR failed, and not because at some point the source was occluded for 2~ seconds.
like i said, i’m fine with it being muddy, uncertain etc. but what it is now is not uncertain, as far as i can tell if you do lose the RWR contact they will 100% always have a passive missile on you. it is actually infallible in the opposite direction it usually is. it is literally impossible to get a launch state, even though the launch criteria is definitely fulfilled.
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@Cik:
apples and oranges is fair.
by the way, they can totally fire multiple sparrows and guide them all. i’ve seen it at least 10 times just in about 30 minutes of testing.
use 7 “incoming missile camera” (only as a test, in the campaign it’s megacheating) you will often see 2+ sparrows maneuvering against you from the same plane. load up dogfight, choose a single F-4E and maneuver into WEZ. it will sometimes choose to fire 2 missiles at you. uh, it might be a uniquely F-4 problem though; i don’t think i’ve ever seen MIG-23s for instance double tap SARH missiles (they will sometimes shoot two AA-7s, but those are those crazy russian heat seeker variants) test it yourself if you don’t believe me. the ACMIs bear it out. they can do it.
(note: i’m not sure which ACMIs you’re talking about because in at least one an F-4 ripples two sparrows within about a second of each other and they both track and slam into the same aircraft about a second apart. i’m not sure if they’re supposed to do that; maybe it’s possible for them to guide multiple sparrows at the same target; i just mention it because i’m not sure.
Ripple firing multiple AIM-7D/Es at the single target was done a lot in Vietnam - when they actually left the rail……
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With out wanting to sound daft or anything but the F4 has always been able to ripple fire its entire load of AIM7’s and guide them against a single target. what it can’t do is guide against multiple targets. This isn’t unique to the F4, all SARH missile equipped aircraft can do it. You need to learn how an SARH missile homes to a painted target. All the carrier aircraft is doing is painting the target with the radar. The missile then homes on the reflected radar energy. The carrier aircraft has NO contact with the missile once launched. Read some books on air combat in Vietnam and you’ll see examples of ripple firing of SARH missiles.
i’m interested. i’ve never been sure if it was possible; in hindsight it makes sense.
nobody knows everything man. if you have any recommended reading though i’ll definitely check it out.
to be fair it’s pretty much irrelevant on the current topic; this happens even if there’s only one missile in the air.
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@Cik:
fine, but you’re telling me that the act of pulling a split -S will disturb these criteria?
Of course.
Search into the Electronic Warfare Fundamentals the chapter about RWR and limitations. (Chap17 If I remember correctly)
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there is no blind spot, that’s horse shit. i’ve been shot from directly under me and above me before and got a perfect launch warning.
It seems to me that the launch warning in BMS is not reacting to this blind zone (you can get it with a -temporary- naked RWR while maneuvering), but there is a blind zone for everything else.
Adding a bias in RWR pseudo distance measurment would totaly break this “cheat”.
Hope to see this one day
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IRL again : selectivity, measurements accurancy, signal processing. In the lribray, if the signal carateristics are “too narrow” (to avoid ambiguities) it is possible that the measured signal doesn’t match the radar spec/missile link signal enough to trigger the Launch alarme (which is not always an evidence of launch, but, depending on missile type, could be only a, a/c radar precific signal/rate/freq/PRI … For a given missile type and launch plateforme, it is possible that the Launch alarm will be trrigered in one case, and not in the other.
Indded … this is “passive cheat”. Because not enough “random” in missile models and RWR behavior … and … hunderds of “trainings” in game (default of the simulation)
Adding a bias in RWR pseudo distance measurment would totaly break this “cheat”.
THIS , just please add this for next update
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Of course.
Search into the Electronic Warfare Fundamentals the chapter about RWR and limitations. (Chap17 If I remember correctly)
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its all very well talking about the realworld limitations (which we all hope are modelled better in BMS one day) but its not really relevant to the discussion which is about BMS and how it works in BMS.
for what its worth, the article you link indicates that manouvering will cause your RWR to display wrong azimuth locations and to display the wrong number of threats, but if he is being CW spiked, it should be aware of that - despite the inaccuracy in the system. it has to be considered a little bit strange that an F4 spikes him the entire time, and that the RWR drops the threat entirely. if the processor was able to recognise the spike and CW in the first place, it shouldn’t just drop it entirely, regardless of manouvering. it might lose it in the blindzones if he stays there, and sure, it might display multiple F4 spikes or an inaccurate azimuth for a few seconds, but once he stabilises again, the RWR should regain some of its accuracy. eitherway the plane is supposedly being painted. the RWR should recognise this. We know the RWR is overmodelled - there is thus no reason for it to behave this way, unless it is explictly modelled this way. perhaps it would be more constructive to have someone that is familiar with the RWR modelling in BMS (not how it works in RL) to answer.
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It seems to me that the launch warning in BMS is not reacting to this blind zone (you can get it with a -temporary- naked RWR while maneuvering), but there is a blind zone for everything else.
Hope to see this one day
read further in the thread. it will; though it’s probably technically impossible to stay in blind the whole time the missile is tracking (you’ll hit the ground) if you are fired upon while they are in blind you will get no warning. you probably won’t see the plane either (in this case ^4) generally it’s not going to happen though, you’d have to purposefully time your maneuver to coincide with the enemy launch which is tricky.
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Cik
A radio “antenna” is a tunned and directional passive receiving device.
Its physical dimensions determine its ability to harmonize to a bandwidth of interest. in this case those frequencies we call “Radar”
Its an analogue practical device not a theoretical digital receiver, its performance is relative to a number of variables. It is fallible.Two basic types that you will be familiar with.
First a “Whip” antenna found and used everywhere from Car AM/FM radios, CBs, hand held 2way, aircraft ect, is a single element conductor mounted perpendicular against a ground plane (second element). It harmonizes with (sensitive to, receives) radiation from a source at right angles (perpendicular) to its orientation.
If it points “up” it will receive from transmitters in any direction on the ground surface 360deg around it.A two element antenna for example a TV receiver or those “T” ribbon type ones you get with your home Stereo Radio/Theatre Systems you stick on an inside wall.
These are mounted horizontal and at right angle to the transmitter source. ( For a TV you point it at the tower on the hill over there)The whole point of this post it that ALL antennas are directional and this is what Falcon tries to simulate in its RWR receiver.
One might say lets mount a few more antennas to cover those blind spots. But there’s only so much room of the F-16 and it already has another half dozen or more radio system on board and antenna placement is an “art” for an aircraft that is expected to travel above the speed of sound and not effect other systems.
And again a split S is not a good manoeuvre if your trying to become invisible to a Radar Transmitter/receiver like a threat aircraft. It will place your RWR receiving antenna in a direct radial line pointing at the source (no received signal) for a period of time.
Now you might say lets put a better Signal processor on the F-16 to keep track of possible threats ? Shore you could and improve other system while your at it.
But how heavy do you want it to be. Even now the current Blks are reported less agile then their predecessors. So we end up with a fighter devoid of the design characteristics that made it so beloved.I’m not trying to talk down to you and I don’t think your stupid, so as Gyro would say take it or leave it.
Regards……Shad
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you’re explaining the principles of something i already know.
you aren’t even addressing anything in my post at all, just talking past me.
your comment about the split S for instance is entirely superfluous in this discussion.
i’m pointing out a fault in the RWR’s handling of receiving a launch state. if it receives a launch state it will warn you. in this circumstance, due to a faulty handling of blind spots, it will not warn you even if the missile is on you for an arbitrary amount of time. that missile could be in track for 20 minutes, the F-4 pinging the merry hell out of you from ANY direction, front left back right whatever. it will NEVER register a launch state, even though one is continuous and ongoing for however long. are you saying that this is how the real plane functions? that’s totally nonsensical. dee-jay himself said that the RWR does not update every second, but it DOES UPDATE. eventually it will realize “hey i’m being shot!” and warn you again. it doesn’t. if it took 20 seconds to do so and that was how the real thing functions, i would be fine with it. the fact that it never does is clearly out of whack. to replicate this in real life the RWR would have to:
receive radar ping
analyze activity
fit to criteria
warn pilot of launch state
lose contact
receive radar ping (again)
analyze activity
fit to criteria
DECIDE NOT TO WARN PILOT OF LAUNCH STATEit’s not that the enemy plane is even INVISIBLE. it is receiving a constant hammering by the F-4s radar. it even shows up on the RWR! the RWR knows the plane is there. it knows it’s being hardlocked and fired on because it’s matching the signal to criteria. it chooses not to warn you because it’s handling is BROKE.
does that sound like something that would be built into a plane? what? it makes no sense.
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@Cik:
WARN PILOT OF LAUNCH STATE
This exact “feature” is totally wrong in Falcon, due to lack of specific knowledge (back then).
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This exact “feature” is totally wrong in Falcon, due to lack of specific knowledge (back then).
source?
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Cik
Please explain too me why you would or should get a launch warning from a F-4 firing a Aim-7
Please do……
PS: I’m not much help to you, am I.
Aim 7 is a dumb weapon it emits no radiation of its own (except maybe its proximity fuse, I don’t remember if its magnetic or radar).
The F-4 must maintain SST on the target continually “painting” while the missile is in the Air.
The F-4 has no data link with the missile so nothing changes during or after launch. There is no hand off to a separate tracking radar as with some Sam systems.
Its similar to a heater except for the illumination source and its spectrum.PPS:
“The launching aircraft will illuminate the target with its radar. In radars of the 1950s these were single target tracking devices using a nutating horn as part of the antenna. This caused the beam to be swept in a small cone. Signal processing would be applied to determine the direction of maximum illumination and so develop a signal to steer the antenna toward the target. The missile detects the reflected signal from the target with a high gain antenna in a similar fashion and steers the entire missile toward closure with the target. The missile guidance also samples a portion of the illuminating signal via rearward pointing waveguides. The comparison of these two signals enabled logic circuits to determine the true target reflection signal, even if the target were to eject radar-reflecting chaff.” Wiki -
source?
This has been analyzed twice in the past in other threads, so not going to say much more here. Some facts to remember:
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Current Falcon / BMS simulates APG-68(v)5~7, with minor features from next versions added to this
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APG-68(v)9 on the Blocks 50/52 (in production as the standard radar version the last decade almost) and with MMC-5000 as also the standard computer has different features than previous configurations, some analyzed in older thread discussions
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MMC-7000 new computer installed to the latest “+ Advanced” birds (e.g. Block 50+ Advanced of THK and 52+ Adv of HAF, Poland, and the last couple of countries that ordered the viper recently) gives additional features to the radar
PS: The above have little to do with the thread’s main question. It is interesting though since it is similar in relation to the old Mirage 2000’s firing the Matra-530 missile against a viper, which is a valid scenario to this part of the world…
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This has been analyzed twice in the past in other threads, so not going to say much more here. Some facts to remember:
-
Current Falcon / BMS simulates APG-68(v)5~7, with minor features from next versions added to this
-
APG-68(v)9 on the Blocks 50/52 (in production as the standard radar version the last decade almost) and with MMC-5000 as also the standard computer has different features than previous configurations, some analyzed in older thread discussions
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MMC-7000 new computer installed to the latest “+ Advanced” birds (e.g. Block 50+ Advanced of THK and 52+ Adv of HAF, Poland, and the last couple of countries that ordered the viper recently) gives additional features to the radar
PS: The above have little to do with the thread’s main question. It is interesting though since it is similar in relation to the old Mirage 2000’s firing the Matra-530 missile against a viper, which is a valid scenario to this part of the world…
none of that has any relation to the the F-4 radar locking the F-16 though. Unless you are saying that all radars in BMS work like an APG-68?
From my understanding (hardly an expert one at that) the ALR-69 determines the launch state of SARH missiles by the detection of CW radar energy.
Im not certain how those facts are meant to affect this.
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Cik
Please explain too me why you would or should get a launch warning from a F-4 firing a Aim-7
Please do……
PS: I’m not much help to you, am I.
because a SARH missile (due to lack of a ARH seekerhead, as contained in the AIM-120 and R-77) requires a very accurate fix on an enemy aircraft, and to obtain a very accurate fix on an aircraft, you have to ‘scan’ (probably not the correct word) very aggressively. whereas to just realize it’s there you don’t have to be as ‘aggressive’ as you don’t need terminal guidance. you just need know if there’s a metal object flying somewhere within a small area.
you could technically design a radar that could terminal without a very aggressive fix, however you’d miss all the time because your “echolocation” would have said the plane was for instance, a small distance away from where it actually was.
effectively, you can’t guide a missile directly onto target without a very aggressive ‘ping’ the RWR has a collection of profiles, so ideally (not all the time, of course) it knows that it’s being illuminated by a certain type of plane (due to it’s profile, strength at range, scan characteristics etc etc) and where it is (which direction the energy’s coming from; probably not very precise) and in what activity state it is in (fast, slow, intense, nonintense) the RWR can recognize a low activity from a high activity, and once it detects high activity it triggers a warning on the (probably pretty good) guess that you’re being shot.
of course, in real life i’m sure it fails all the time. and that’s cool; if BMS wants to model RWR failure i’m all for it. but this isn’t really RWR failure, or at least not in a way that makes any sense. it’s i guess kind of a ‘reverse exploit’. it’s not an advantage of course, but the fact that something disappearing on your RWR for one second allows it to guide a missile towards you at full hardlock without a warning for an arbitrary length of time is not modelling reality correctly. in theory, there should be no difference between a rotate-through-blind hardlock and a regular hardlock; it’s not in blind, it’s hardlocking you, it should be detected (if indeed the RWR does not fail)
say 4.33 comes around and the RWR is modelled to fail. you are in merge with a SARH carrying fighter; the fighter fires at you. RWR detects the launch, you pull a split S which rotates you through blind. you pull out, you are out of blind. RWR should pick up the energy hitting you again just as it would if you have never done the maneuver at all; the energy is still hitting your plane and the RWR should have a chance to detect it. if it then FAILS due to the RWR being fallible, there is no problem. you could do that maneuver again and this time it might not work. or it might. who knows. maybe you’ll never detect the launch at all and die. that’s OK though, because it’s due to the fallibility of the RWR and not this really weird issue wherein the RWR just fails to warn you, even though it has no reason not to know it’s being hardlocked, at the least.
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when guiding a sparrow (and many other missiles), the radar must use a specific type of radar emission, known as a continuous wave. it is the detection of this type of radar signal that triggers the launch warning.
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when guiding a sparrow (and many other missiles), the radar must use a specific type of radar emission, known as a continuous wave. it is the detection of this type of radar signal that triggers the launch warning.
trufax? neat.
i do need to read more stuff about early missile combat.
also i did always wonder how it picked out a launch from just a run of the mill hardlock. i wasn’t sure if the launch was more intense, or what.
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Some HUD tapes/audio seem to suggest that STT locks or even GCA radar can trigger launch warnings IRL. But I may be completely wrong, or may be on older generation systems
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thats because STT locks use CW energy… it cant tell if you launch or not, but it can tell if you STT them - and as thats required for (older) missile launch, its a reasonable assumption that a missile launch is associated with it.