Possible active radar missile bug (very serious issue)
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Surely it’s all down to the software and hardware combinations used - and that the seeker still needs to use Doppler shift to filter out any clutter.
Chaff has a velocity - even though its only given at 1.2m/s - but if you filter out clutter based on velocity difference then you still filter out anything else at relative velocity. You would need the missile seeker to lock onto the chaff for a significant amount of time so it doesn’t reacquire you - Not so easy these days maybe:
Therefore you could surmise that older AHM including the AIM-54A/C/ECCM and even AIM-120A could have been susceptible without sufficient processing power.
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Ill not be at home for the next few days.
Would someone test a propper defensive manouver against an AIM54?Thus:
- Put missile on the beam
- start popping chaffs (a program of 15-20 or more)
- turn hard to put your self on the opposite side of the chaffs so it’s blocking the weapon’s radar.
If indeed the AIM120B and simmelar (or newer) missiles do fall for this trick I’d say leave the discussion. Then the weapon and chaffs are propperly modelled. Or atleast plausibly correct modelled.
If the older weapons act the same as the AIM120B/C…we may end up with another 30 page thread noone really reads anymore. -
How comes any T.O to fixing a bug…??? :roll:
We have a major BUG and not feature modeling issue…
Molni, have you considered that maybe a bug or modeling problem (not sure which) is not with ARH missiles but with the chaff instead? I would just like to add that as a possibility, as the US Air Force addressed this problem in the 1980’s. http://www.dtic.mil/dtic/tr/fulltext/u2/a164106.pdf
Please understand that I am not trying to fan any flames here, I just want you to consider the complexity of the problem, so that you can maybe understand that the dev’s may have more to consider than just missile modeling or bugs. As some have stated already, changing the model of a missile could have a negative impact on the game.
As a curiosity, I wonder if in a MP scenario (I only play SP) if you are tracking one target in an open area and he/she deploys chaff bundles, would you see multiple returns on the FCR? If no, then I would be looking at chaff as the problem more than the missile itself, as it would stand to reason that if the FCR cannot “see” the decoy, neither can the missiles’ Active Radar.
I have no expertise in any of this at all, so I may be way off. I am just looking at the problem from different angles here and see that logically, the problem could lie elsewhere.
As a side note, this problem is not the end of the world, nor does it make the game unplayable. That being said, I am sure you are a great guy (even though you called me “fanboy” in another post…lol) and I know English is not your first language, but you tend to come across as passive-aggressive at times, especially when given an answer you don’t want to hear. Your usage of sarcasm and huge, bold fonts in some of your posts suggest anger in the eyes of some. I know you must have spent many hours testing and am wondering if your getting enough sleep. I say this because I truly think you mean well, you are just projecting yourself poorly at times. This can sometimes happen when one does not get enough sleep…my wife would tell you I behave the same way if I stay up 'till 2 AM in the Sim and then get up at 6 AM to go to work!
Anyway, none of my criticisms were meant to be offensive. Just trying to help you understand some of the animosity I have noticed between you and others on the forum.
BTW, I know you have had a hand in some of the releases for this SIM and just wanted to thank you for your time and effort.
schnidrman
P.S. A couple of interesting links about chaff and deployment methods.
http://www.globalsecurity.org/military/systems/aircraft/systems/chaff.htm
http://www.frontline-defence.com/Defence/index_archives.php?page=1745I know the second link deals with Naval Ships, but found it interesting nonetheless.
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F-16 radar should not display chaff returns at all… it is a PD radar.
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F-16 radar should not display chaff returns at all… it is a PD radar.
Thanks Blu, didn’t know for sure. However, someone asked earlier in the thread if newer ARH missiles used Pulse Doppler. Never saw an answer to that question so I’ll ask/answer this. Do PD radar systems not see the chaff or is it simply considered a false signature and not reported to the screen? Would a Slammer w/ PD radar have the intelligence to ignore the chaff and continue on target?
In my P.S. I gave a couple of links. The first one mainly talks of chaff usage in flight and states that “Specific descriptions of how chaff or flares are actually employed in training for a combat situation are not releasable.”
It also states that “Chaff is intended to act as decoy for radar and/or increase ground clutter at the same time. However, modern pulse-doppler radar can recognize such decoys, especially in the lookdown/shootdown mode. This is particularly true because simple decoys, in contrast to true targets, do not exhibit a corresponding doppler shift in the radar band.”From that standpoint I would say if you have a AA missile coming at you and it is using PD radar you had better out fly it or your just a clay pigeon. Even if your pumping out a dump truck load of chaff. Fortunately (for the sake of the world and not our beloved sim!) we haven’t seen or at least haven’t heard of any BVR missile exchanges with a Russian built v. US built modern fighters. I think it would have a high probability of a mutual kill scenario.
This is not to say that I don’t think chaff should be used v. PD radars, I just don’t think it is effective without proper evasion techniques. Even if the PD radar has the ability to “see” the difference between the target and the decoy, it still has to process the info and act on it so even if you slow the computer down by only .001 seconds, it could be the difference maker. Maybe that’s why a Mig will turn tail and run from a AIM120 shot at RMax and survive.
I welcome all replies and criticisms to this as I am very curious about this subject. I am in no way saying any one is right or wrong on this thread and as I stated previously…
I have no expertise in any of this at all, so I may be way off. I am just looking at the problem from different angles here and see that logically, the problem could lie elsewhere.
:drink:
schnidrman -
d. Against Doppler radars, self-protection chaff is most effective when
dispensed at or near the beam, relative to the threat radar. When chaff is
dispensed in the airstream, the drag on an individual dipole is so great compared
to its mass that it slows to the velocity of the surrounding air mass almost
instantly. Since the relative velocity of the chaff, in relation to the radar, is zero,
radar systems employing Doppler processing and tracking will not display the
chaff. Doppler processing radars will continue to track the aircraft unless it also
has a relative velocity of zero. This occurs when the aircraft is abeam the radar.
Chaff corridor and area saturation tactics against Doppler tracking radars will
have limited effectiveness.c. Self-protection chaff tactics are based on the use of chaff dispensers that
use burst chaff dispensing techniques to defeat a TTR. Burst chaff dispensing,
employed during the final phase of an engagement by air-to-air or surface-to-air
weapons, can generate tracking errors or a radar break-lock. Burst chaff
effectiveness is greatly enhanced when accompanied by jamming and evasive
maneuvers (Figure 13-13).(1) Self-protection chaff has proven effective against all pulse radar threat
systems when employed with maneuvers and jamming. This is especially true for
TTRs operating in an automatic tracking mode.Chaff employed against a monopulse radar is designed to put
multiple targets in at least two of the tracking beams (Figure 13-16). This
generates errors in the azimuth, elevation, and range tracking circuits. Multiple
chaff targets continue to generate azimuth and elevation errors that can
eventually generate a break-lock condition, as the radar transfers lock-on to the
chaff. Chaff is most effective against monopulse radars when employed on the
beam in order to create the maximum angular tracking error.(d) Modern radars may employ some form of Doppler filtering to negate
the effectiveness of chaff and other sources of clutter. Pulse Doppler and
continuous wave radar systems track targets based on target velocity relative to
the radar. Radars employing a moving target indicator (MTI) use relative target
velocity to distinguish between targets and clutter. Chaff slows to near zero
relative velocity almost immediately after dispensing. For self-protection chaff to
be effective, the aircraft velocity relative to the radar site must also be near zero
This occurs when the aircraft’s aspect to the radar is 90°, or on the beam. By
maneuvering to a beam aspect against a Doppler radar, the pilot is exploiting the
“notch” where radar cannot discriminate targets based on Doppler frequency
shift (Figure 13-17).if you are curious on this topic, you can find the document that these were pulled from @ : http://www.blu3wolf.com/falconbms/docs/Electronic-Warfare-Fundamentals.pdf
http://www.blu3wolf.com/falconbms/docs/ has a few more interesting docs.
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Thanks for the info Blu. Good stuff here!
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Molni, have you considered that maybe a bug or modeling problem (not sure which) is not with ARH missiles but with the chaff instead?
I do not know what cause the problem, the point of bug report that regardless how big is the chaff chance value it does not have effect. This is bug. Why? Falcon always worked that way that even with low chance but chaff worked. The low chance is caused by the distance modifier and the database value.
In my tests you can see in FF4 happened what you could expect. With original modeling values you have very low chance for defeat but you have. If you increase dramatically the chaff chance the defeat becomes easy as has to be. Very simple and 100% coherent result. In BMS4 regardless what you set ARHs are immune to chaff. But if you do this with SAM or AC radars SARH missiles and SAMs will have the same nature as in FF4 the ARHs. 1-2 chaff and the lock is defeated. These clearly shows that something is wrong with ARHs and rest of radar guided missiles are good. (With SARH missiles you can get the same result is all Falcon version.)
So pls. stop post any feature modeling realated sources and stop discussion about this. Why? Because pointless, this is not a modeling issue.
I do not know that code but after 10+ Falcon and 5+ year modding I know how worked and how should work ARHs because were long time periods when they worked… Because of DB literally did not changed since SP4 it is sure that not the DB and other dat file based modeling values are the problem, therefore this also validates this is not a modeling issue.
In an alpha version of FF5 changing the the chaff caused this somehow, of course I have no idea why. Maybe it is only a coincidence, but between BMS4 and OF the chaff changed and BMS4 now has 100% the same symptom as FF5 alpha had. It would be great if some FF member be here and remember what was changed then fixed.
I just want you to consider the complexity of the problem, so that you can maybe understand that the dev’s may have more to consider than just missile modeling or bugs.
Problems are not so complex if you examine only one variable in the equation. How lucky we are, the chaff chance is the only variable in what was changed an tested and was prooven that does not have any effect which is a major bug.
As some have stated already, changing the model of a missile could have a negative impact on the game.
I did not requested to change the model, I reported a bug which I found via tweaking.
(IMHO the range modifier should be changed but I never requested this because I’m aware that never will happen. Onply problem that ruin the game because of the AI…) Increased chaff chance value has positive effect on gameplay especially in single player game.As a curiosity, I wonder if in a MP scenario (I only play SP) if you are tracking one target in an open area and he/she deploys chaff bundles, would you see multiple returns on the FCR?
No one of Falcon worked this way. I dot know whay posted this because if you ever played Falcon you should know this.
As a side note, this problem is not the end of the world, nor does it make the game unplayable.
From your aspect maybe. From my aspect it does. The whole class of AA missiles cannot be defeated by chaff. This means against AI as long as they launched withing NEZ and AI or player does not perfrom well defensive turns they has 100% hit and kill ratio. It is a bit funny to me saying that “this is not an issue”. IMHO, this is showstopper issue. Would you say the same if all IR missiles be immune to flares…? I doubt… They are the same case.
Anyway, none of my criticisms were meant to be offensive.
Roger. I also do not want be jerk but somehow my style suggests offensive behavior. I simply do not understand why. I posted a bug report with 100% coheret test result. OF course I did not recorded all the 100+ launches and MP test because I do have so much time, but I did them. And some people still try find another reasons instead admire that “Houston we have a problem”….
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So pls. stop post any feature modeling realated sources and stop discussion about this. Why? Because pointless, this is not a modeling issue.
can we get a link to your demonstration videos?
I’d like to see how you tested these factors.
can anyone provide some insight into how complicated the coding is for chaff? does it take into account chaff location between TTR and target, bloom rate, doppler shift for beam vs head/tail aspect, or is it simply a chance to drop lock when chaff is released?
if the code is so simple, then molni is right, this is a modelling bug.
if the code takes any of the above factors into account, then the testing could be in question.
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I think molny talked about the fact that he can’t get a missile to miss with dropping chaffs, no matter what numbers he put into the sim. Not if the missile would be affected by chaffs or not IRL or should be in the sim. He just can’t make the missile bad, sort of? And that’s why he says the code does not work?
Cheers
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naah… many people (me too) just get frustrated because Falcon 4 is always some sort of mix of leftovers … Somethings are better in FF, some in AF, Some in RV, some in bms …list goes on…
There is always somethings broken when some are fixed. BMS fixed flight model, no more fly on rails but game side is bit broken or maybe i should say WIP.
And these threads are long as hell because if some one points bug, there is least 10 fanboy’s to defend …
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I think molny talked about the fact that he can’t get a missile to miss with dropping chaffs, no matter what numbers he put into the sim. Not if the missile would be affected by chaffs or not IRL or should be in the sim. He just can’t make the missile bad, sort of? And that’s why he says the code does not work?
Cheers
and I just questioned how relevant the numbers were to his test results.
the numbers, mason! what do they mean?
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In FF4 is the relock exist but you can break the lock again. The relock can happen if only you are so dumb that you do not make turns. Because of the big relative position change and the time for relock the capability is theoretical, missile is not able to perform again.
In BMS4 you cannot break the second lock and mostly not even the first lock. I uninstalled the FF4 but if you wish I reinstall again and I make some videos if you wish…
I am seeing the break of the first lock sometimes now, but it does not allow enough time for a position change to prevent a second lock. (once I had a little more time, got a nice bit of a turn, but it still relocked, and no luck breaking second lock as you say).
I am of course referring to active with ‘M’ in RWR. Not just break off the rails unlock.
It is hard to break the first lock, but is possible. I am agreeing with what you see.
If we developed a good skill to break first lock (as it is) , and had more time to prevent second lock would you be okay with it like that? I know you expressed concern about the AI, so wouldn’t they still be in trouble even if it worked like this?
We don’t want it to be magic chaff, but how could we have it so that it required good human skill to defeat with chaff (with turn, appropriate chaff program, etc) AND give AI a shot at it too?
In other words, could you live with it if only skilled human pilot can do it. Maybe easier to code a fix like that???
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can we get a link to your demonstration videos?
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……
I did not record ACMI because it does not show what you can see or RWR. So, what should I record on ACMI with what version to see that chaff does not work against ARH in BMS4…?You know what would be good right about now: ACMI>options>missle lock line
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can someone tell me what is chaff program settings for molnibalage BMS4-test for the first encounter, the one with chaff chance 0.99
my video player I can’t see it too good.thanks
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Blimey…haven’t thought about this one in ages (think circa 2009).
Once upon a time, a slammer was subject to a significant vulnerability to chaff decoys if there was some beam aspect to the target in view. Around about the time that the HPRF/MPRF modeling was added, input from knowledgeable real world sources who are in a position to know described that decoy modeling as BS for current inventory slammers. As a result, the code was changed to better reflect the reality of that situation. The factors that affect that beam magnifier effect are and always have been internal to the code, not directly related to the chaff chance in the radar data, although those factors do operate on the chance value for the “dice roll” calculation.
Net upshot?? Yep, slammers are very nearly but not totally immune to chaff.
This is by design, not a bug. Absent hard data to the contrary, there’s no plan to change this.
Nuance… So there is no modeling for block or national variants of the slammers really. As a result, we’re led to believe that in some cases, slammers fired from national variant F-16’s might be a little better at countermeasures avoidance than they should be versus real world inventory expected performance. That’s a criticism that would be hard to defend. It’s also one that would be hard to calibrate since we have no more data/detail on the differences (for obvious reasons) beyond that anecdotal comment. In the same way that support for older viper blocks is being added to future code, we may split out modeling of older missile blocks but as with all things future, no promises.
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This is by design, not a bug. Absent hard data to the contrary, there’s no plan to change this.
Nuance… So there is no modeling for block or national variants of the slammers really. As a result, we’re led to believe that in some cases, slammers fired from national variant F-16’s might be a little better at countermeasures avoidance than they should be versus real world inventory expected performance. That’s a criticism that would be hard to defend. It’s also one that would be hard to calibrate since we have no more data/detail on the differences (for obvious reasons) beyond that anecdotal comment. In the same way that support for older viper blocks is being added to future code, we may split out modeling of older missile blocks but as with all things future, no promises.
So if I understand this correctly the only ARH behaviour supported, by virtue of hard-coding, is one AIM-120 model?
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As far as the decoy effectiveness is concerned, and that’s all we’re talking about here remember, there has only ever been one code path for all ARH missiles. That code path reflects best understanding of slammer behavior; it does now, it did before. The difference compared to older versions is that the current one is less susceptible to chaff; this effect is more pronounced the more beam aspect is involved. In the older setup, missile seekers looking at targets near beam aspect would be significantly more susceptible to chaff. Now they aren’t as much.