AIM120 HPRF/MPRF signature in your RWR
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Hello again, does any Dev have a start of an answer about these questions ? thx
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Hello again, does any Dev have a start of an answer about these questions ? thx
I’m not best qualified to answer fully, but the AI does not rely solely on his RWR to begin executing defensive manouvers - it is a lot smarter than that.
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The AI is able to take defensive action far before detecting the missile in his rwr depending on his assessment of the tactical situation
It is also able to visual detect trails by day and missile flame by night
The AI does not have a super rwr and does not detect aim120 emissions before MPR
That’s for the theory
We are not immune to bugs though
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These are some observations after “calibrated” tests in Dogfight / Match play of a F16 block52 against a “cooperative Human” F16 Block 52. The purpose was to investigate “signature” of the AIM120 in the enemy’s RWR based on different RCS selection.
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Depending of RCS selection of the AIM120, the MPRF radar mode will activate at roughly 12 nm slant range of the target in LARGE and 8nm in Medium/small. However, the target can observe the <m>on its RWR roughly when the missile is at 8 to 7 nm from him. In case the fox3 shoot is made in RCS=LARGE, i would have expected to see a <m>sooner as the MPRF mode is actively tracking since 12 nm slant range.
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If you snip the target shortly after launch (snip was made by turning radar off to ensure AMDL was no more effective and missile could only use guidance from HPRF -I hope this is simulated like this ….), you can observe HPRF mode is actively tracking the target at slant range as long as 18 nm. This was evidenced on TACVIEW when seeing the missile turn toward the manoeuvering target at 18 nm while the target initiated the turn only AFTER the AMDL was interrupted. However, the target RWR does display the <m>ONLY when the missile switches to MPRF. No <m>is displayed on the target RWR while my missile is tracking in HPRF phase.</m></m></m></m>
These seem like possible issues - might be worth tracking at https://bmsbugs.blu3wolf.com/
If you do, there are some instructions on filing an effective report here: https://www.benchmarksims.org/forum/showthread.php?40871-BMSBugs-A-public-third-party-BMS-bugtracker
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- Depending of RCS selection of the AIM120, the MPRF radar mode will activate at roughly 12 nm slant range of the target in LARGE and 8nm in Medium/small. However, the target can observe the <m>on its RWR roughly when the missile is at 8 to 7 nm from him. In case the fox3 shoot is made in RCS=LARGE, i would have expected to see a <m>sooner as the MPRF mode is actively tracking since 12 nm slant range.</m></m>
I’d like to stress that your RCS selection is NEVER changing anything for the missile. The missile turns its radar on based on its algorithm and the resulting wake-up point. What changes with the RCS selection is the displayed information in your pit. Truly, the A-Pole, M-Pole indicated in the pit are only calculated/ assumed points as your pit can only do some maths (knowing the behaviour and the algorithm of the 120). Whether or not your missile really is HUSKY or PITBULL, only the missile knows! There is no backwards DL from the missile telling the F-16 “hey i am at pitbull”, not in the versions implemented!
If you snip after launch (cheap-shot), the missile flies to the preset wake-up point and then (if you are lucky) tracks the target that should be there.
Enemy is indeed AFAIK behaving after assessing the situation and by knowing the enemy. I guess also you know about the enemy and are working with DR/MAR rather than waiting for an incoming “M”.
stingray
S
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Bug identified
AI reacts to aim120 turning HPRF
Thanks for the report
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Truly, the A-Pole, M-Pole indicated in the pit are only calculated/ assumed points as your pit can only do some maths (knowing the behaviour and the algorithm of the 120). Whether or not your missile really is HUSKY or PITBULL, only the missile knows! There is no backwards DL from the missile telling the F-16 “hey i am at pitbull”, not in the versions implemented!
Didn’t we get an <m>on RWR as soon as an inbound Aim-120 is in HPRF active stage? (4.34 and prior) Since, according to the docs, it’s the first state in which it starts emitting with its own RDR. - Assuming the calculated timings from the MMC for each RDR stage are on point, and are matching the MOI conditions. (It probably never will, but only theorically speaking)
If that is still the case, it makes perfectly sense that the AI shows at least some sort of reaction as a consequence.</m>
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The purpose of the original post was to highlight some kind of extra-capability in the RWR of AI-operated aircraft.
Tests revealed that :- the RWR of an aircraft operated by human will not display a <m>until the incoming AIM120 is roughly 8 Nm from the target, that is most probably in MPRF/Pitbull active guidance
- the RWR of an AI-operated aircraft seems to detetct an incoming AIM120 much farther, as far as 19 Nm. This was the distance indicated in the HUD where the AIM120 was supposed to go HPRF/Husky during the cheap shot.
This is not really “fair” => The same RWR should have the same capability wether the aircraft is operated by human or AI.
I don’t know what the bug was and how it was corrected, Mav-JP will probably tell us more, but i would expect :
- either RWR will display a <m>at some point of the HPRF active guidance, providing everybody (human AND AI) with a more sooner alert of the threat (not just only the AI)
- or RWR still behaves as in 4.35U1, indicating only the <m>when AIM120 is in MPRF for both human AND AI, which should in turn increase our AIM120 PK against lower levels of AI which will not be able to take advantage of their super-RWR to engage defensive actions</m></m></m>
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May be we have to think that AIs have disadvantage concerning the tactics part. It is certainly unfair to react at hprf state but consider that the AIs “do not know” what is MAR and their tactics are very basic.
Think that you have a human and not an AI. The human player would react much more further than 8 miles due to MAR consideration. If this can simulated with the AIs then it is right to change AIs’ RWR but if this is not possible i think that it would be very easy to kill non human players.
So we may consider that this “bug” can simulate a basic human reaction from the AIs.
Just an idea. Devs know better and they can run tests too or release a beta to certain people in order to be tested in a larger scale (a campaign may be).
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May be we have to think that AIs have disadvantage concerning the tactics part. It is certainly unfair to react at hprf state but consider that the AIs “do not know” what is MAR and their tactics are very basic.
Think that you have a human and not an AI. The human player would react much more further than 8 miles due to MAR consideration. If this can simulated with the AIs then it is right to change AIs’ RWR but if this is not possible i think that it would be very easy to kill non human players.
So we may consider that this “bug” can simulate a basic human reaction from the AIs.
Just an idea. Devs know better and they can run tests too or release a beta to certain people in order to be tested in a larger scale (a campaign may be).
After what Mav-JP did with AI tactics, I’m not too worried about introducing MAR, if not done already, or tweaking it. What I believe more is that he wouldn’t be satisfied with a bug mimiking reality. That really doesn’t sound like his style. At the moment, we have AI mimiking peeps who need to RTFM the A/G section of the manual, and I think this is clearly not the standard he wants to stop at on a longer term.
Now, everyone do what they can with what they have. -
For your information the issue is not only the hprf/mprf thing
There are issues with AI detecting players missiles in MP, it’s known since November last year
This will take a little bit more than 3/4 weeks for the fix to come to you guys
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the hprf/mprf thing
I’ve been trying to follow along here but I feel like I don’t understand what HPRF is. Why should it not register on RWR?
Are there any unclassified resources (docs or vids etc) that describe HPRF and MPRF at a technical level (frequency bands, wattage, etc)?
All I gather is it’s a mode tuned for high-aspect / closure-rate… and ostensibly higher pulse repetition frequency.
Is it just a quirk of the ALR-56 that it doesn’t pick it up… but what do we know about other planes, esp. Russian, Chinese, etc. I suppose there’s probably a matrix of what planes can detect which other planes/missiles. (eg. older block Migs or even Iranian F-14s etc may not even know what an amraam looks like, hprf or mprf.)
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Linking this thread from 2018 with some good insight, from folks who sound like they know … but still not clear why HPRF would be invisible on RWR.
https://www.benchmarksims.org/forum/showthread.php?34452-HPRF-MPRF-amp-RWR-Symbols&highlight=hprf+mprf+rwr -
Would suggest there is not a lot useful in that thread… At least, for the case of 4.5th generation fighters with western avionics/EW.
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I’ve been trying to follow along here but I feel like I don’t understand what HPRF is. Why should it not register on RWR?
Are there any unclassified resources (docs or vids etc) that describe HPRF and MPRF at a technical level (frequency bands, wattage, etc)?
All I gather is it’s a mode tuned for high-aspect / closure-rate… and ostensibly higher pulse repetition frequency.
Is it just a quirk of the ALR-56 that it doesn’t pick it up… but what do we know about other planes, esp. Russian, Chinese, etc. I suppose there’s probably a matrix of what planes can detect which other planes/missiles. (eg. older block Migs or even Iranian F-14s etc may not even know what an amraam looks like, hprf or mprf.)
HPRF is a much weaker mode than mprf
Should it be seen by alr56 is totally unknown
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Well, imho, every xmit has its “burnthrough” range where it can be picked-up by listening eq. , in this case , the rwr. (which is a pretty good/sophisticated listening device, given the use case)
“burnthrough” = i didn’t mean jamming burnthrough here , but the range when rwr picks-up something, when db’s/mW are sufficient to detect even classify as “painting equipment” , you know, the brushWe can assume that all radars are heard at 1/4 further then their effective range (or more) , so we can “hear” them pretty much further then they can “see” us, give return.
While HPRF is maybe quiet, given low-power xmit, small radar, but it’s not oh so quiet as it close up our rwr ,… while I could believe that maybe it has some logic that controls xmit pwr , maintaining the return picture , contact… while keeping xmit power at the minimum required … SciFi … but not impossible…
Eg… As the sub/ship uses active sonar, eg… you want bigger range , you pump up the source kW … more kW = more nmi , better returns … and more dead whales/doplhins … eheh , and heard by everyone in vicinity , ~50nmi ??
So is it HPRF detectable., yes I believe so … at what range … ??? Probably before impact/miss in any case., when close enough. - its not the frequency/band/repetition pulse, but dB’s/mW of “known” noise which are listened for…
If H(arm)AS can pick-up 10-30kW at more then its range , why RWR couldn’t pick up 10W at 5-10nm … - that power is sufficient for radio/modem comms at even longer ranges
…just sayinCheers
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HPRF is a much weaker mode than mprf
Should it be seen by alr56 is totally unknown
Thanks … I suppose one other possibility is it “looks” too much like a mode of the APG-68 and RWR can’t disambiguate it from launching a/c
I suppose we also don’t really know, the real/various active-radar modes and ranges of the AA-12 then …
What tenets guide decisions, when faced with unknown/classified systems and capabilities … bias for balanced/fun gameplay? Would multiplayer BVR engagements be better or worse, with a slightly longer missile-warning? (I’m too newb to have much of an opinion.)
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Thanks … I suppose one other possibility is it “looks” too much like a mode of the APG-68 and RWR can’t disambiguate it from launching a/c.
As it sounds, it isn’t impossible… but again… scifi… guesswork.
Guiding Fox1 in STT and feeding mid-course correction datalink are technically completely different things… Fox1 STT uses ALL radar power to one bug , while mid-course corr for slammer can be done in RWS/TWS (almost search) modes, - so hence more LPI
We are talking about MPRF/HPRF modes of AMRAAM’s radar , which is not APG68 , so APG has already turned its role to amraam, amraam is active, APG is irrelevant now on.
What could be true ,…
MPRF are more “coarse pings” , larger target = better range = better interception path., but few secs of warning <m>before when it would happen in HPRF mode.
HPRF is high(er) resolution for smaller targets, mig21, helo. - at a bit reduced (radar) range … need 1-2sec longer guiding before active.So, mid-course correction , longer for HPRF - need closer to target , MPRF - you can snip target further , fire and forget
But both modes should trigger RWR when active , … problem is how much LPI is amraam’s radar… range of RWR pickup. - a good probability would be 15nm mprf / 10nm hprf … but…
Cheers</m>
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other way around, white fang - HPRF happens first, then MPRF. HPRF - Husky - works only for high closure rate (high aspect) contacts. I speculate this is due to the high pulse repetition frequency having too many ambiguous speeds for low doppler targets. MPRF - pitbull - activates some time after husky, closer to the target. The medium PRF works with high and low closure targets - speculating here - perhaps due to not having ambiguous speeds at this closer range and lower PRF.
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I haven’t done the math or even drawn this out on a napkin but my speculation would be … at extreme high closure-rate and intercept aspect-angle, the missile may just need a higher frequency of updates in case target begins to maneuver hard.
Thinking… AIM-120 is a 300lb bullet, coming out of its burn at around mach 4…
At colder aspect / slower closure (and also a bit slower missile airspeed) maybe it can afford to ping less frequently (and thus avoid detection, even as it gets closer)?
Again this is just pure, unbridled speculation … I know nothing, just fascinated by the science and engineering that goes into these systems.
I suppose my theory depends on what is the actual timing of the pulse-repetition rates we’re talking about … is MPRF one pulse every 10 seconds or 10 pulses every second. Probably something in between. If MPRF is less than 1 pulse/sec then my theory might make sense.
But … if that is the case, then there’s a condition where it would make sense to stay HPRF all the way into impact, if target is oblivious and continues to fly straight at you? I haven’t heard anyone suggest that it does that. But then again I’ve heard almost nothing, so who knows.