4.37.3 AIM120 AQUISITION MODEL
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@Mav-jp said in 4.37.3 AIM120 AQUISITION MODEL:
Another point is in MP there is a DEad Reckogning model on top of this , which can make the AIM120 pull more lead than in SP
it is clear though that a full rewrite of the Guidance model would maybe help as it seems we might have computation bugs lurking in there
(the guidance model is from Microprose era, we just limited the pursuit according to the FOV / Antenna movement)
Well then I hope for future updates and improvements in the guidance.
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@Mav-jp said in 4.37.3 AIM120 AQUISITION MODEL:
@molnibalage said in 4.37.3 AIM120 AQUISITION MODEL:
Nice.
It is not clear to me the followings:
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How is modeled the radar scan of the missile? Scan rate (angle sec/bars?) If the FRQ of the radar is known based on the size is is an easy calculation to determine the beamwidth. We can assume 10 GHz, almost every ARH uses the FRQ. Is it / will be modeled the scan?
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Where came the info that the AIM-120 is able to operate both with HPRF and MPRF? I have no idea about the modes of the AIM-120. But even the huge R-37M has only HPRF mode based on its detection distance against incoming / receding targets. (~3 times difference. between incoming and receding target of the R-37 could perform both HPRF and MPRF the distance would be only half against receding targets.)
nowhere in the document it says that the AIM120 operates both HPRF and MPRF in the same time,
first there is a HPRF search , THEN a MPRF, never in same time
As far as the SCAN of the missiles radar is concerned, there is no scan modeled , it’s purely algorithmic at that stage. I dont think modeling scanning time will bring anything on the table considering the small size of the UV. It might in edge case reduce the PG a bit, but it’s really really a level of detail that is not worth the effort IMO (it’s already complex enough LOL )
Of course they are in sequence. But imagine the impact of scan time when the detection range of an ARH seeker is just 1/3 against a receding target if the missile is only HPRF capable. The missile in case of loss of track simply can fly-by the target because of the scan time and scanned volume of airspace.
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@suhkoi69 said in 4.37.3 AIM120 AQUISITION MODEL:
@Mav-jp you wrote “One big question mark is: should the UV coverage be dependent on the FCR SubMode as well (i.e. 2.5 x σ of each submode ) ?. It would make sense because that would increase the selectivity without impacting the Probability of guidance at all. However, at that stage, the UV coverage (and thus size) is
independent of the FCR Submode i.e. the selectivity in all FCR Submodes is the same.It might be changed in future release to increase selectivity of STT vs TWS.”could you please explain more?
yes
There are two things separate to really understand
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we need to model in the sim the Error in positioning of the DLPP vs Target. In real, it is is naturally coming from the errors build in the system. In order to simulate this, we had to create an error model and position the DLPP according to this model. SO at the end of this process, the DLPP is placed somwhere around the Target, depending on conditions and of course randomized following the gaussian laws.
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then we need to define which UV will be search by the seeker, this UV is for now defined at 2.5 sigma of all the stochastics parameters of TWS error model. we could envisage to make this UV depends on each Radar Submode , this means that in STT the UV could be 2.5 sigma of STT error model while in TWS the UV could be 2.5 sigma of the TWS error model.
In essence that will not change the PG for a complete mid course tracking, but it will likely improve the selectivity of the STT compared with TWS.
It would however degrade very much the PG of STT in case midcourse track is lost (because the UV would be much smaller then) and i believe it would mean a PG close to zero in STT in those case whereas it would be higher in TWS.
When saying that it sounds weird isnt it ? that’s why we chose to stick to the wider one anyway for the UV search and this modeling makes things looks reasonnable
Maybe the real has a very narrow UV when mid course is complete (for better selectivity) but if Track is lost widens its UV search automatically ? … the possibilities of modeling are huge and certainly the missiles are clever to chose what’s the best option …
it could be done like that, reduces UV if track is maintained , but widens to 2.5 sigma TWS is track is lost ? …interesting idea…but in essence it wont change anything at the end in term of gameplay
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On another hand do we have solid info that regaining a lost lock is impossible? Or is it based on the D/L info you have?
(or am I completely wrong and getting the lock back is improving the DLPP position?)It’s seems weird to me, especially since in TWS as I understand you can loose a track and the system will interpolate the enemy position for a few second giving you time to get the lock back.
Since we are not loosing the connection with the missile but only with the enemy it would make sense that the missile would prefer to take the guidance from the interpolated track rather than going ballistic to the DLPP.
Really talking out of my ass here, no idea how that really works. But currently, against a good jamming enemy we are loosing a lot of lock and trashing a lot of missiles
Thanks!
Mike -
@Mikyjax said in 4.37.3 AIM120 AQUISITION MODEL:
On another hand do we have solid info that regaining a lost lock is impossible? Or is it based on the D/L info you have?
(or am I completely wrong and getting the lock back is improving the DLPP position?)It’s seems weird to me, especially since in TWS as I understand you can loose a track and the system will interpolate the enemy position for a few second giving you time to get the lock back.
Since we are not loosing the connection with the missile but only with the enemy it would make sense that the missile would prefer to take the guidance from the interpolated track rather than going ballistic to the DLPP.
Really talking out of my ass here, no idea how that really works. But currently, against a good jamming enemy we are loosing a lot of lock and trashing a lot of missiles
Thanks!
MikeIn BMs , if you loose lock the DL is lost forever and missile
Is updating DLPP on last DL message parameters.In real no idea
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So this is a pure gameplay choice then?
Since the aim120 is now really nerfed and more realistically modeled compare to earlier do you think that would makes senses to reconsiderate that?There is so much things that I can mess up (and I love it), mistakes that are on me, non respect of the mar, shooting too far, outside of the Circle, bad Sa, bad tactics, bad decision… that when you did “everything correctly” wasting 3 missiles just based on a random loss of lock is a bit frustrating, and that’s only because there is nothing you can do about it. And I’m even talking in STT.
Anyway “BMS will always work that way because we want more challenge” would be fine by me, just asking if it’s worth considering
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@Mikyjax said in 4.37.3 AIM120 AQUISITION MODEL:
So this is a pure gameplay choice then?
Since the aim120 is now really nerfed and more realistically modeled compare to earlier do you think that would makes senses to reconsiderate that?There is so much things that I can mess up (and I love it), mistakes that are on me, non respect of the mar, shooting too far, outside of the Circle, bad Sa, bad tactics, bad decision… that when you did “everything correctly” wasting 3 missiles just based on a random loss of lock is a bit frustrating, and that’s only because there is nothing you can do about it. And I’m even talking in STT.
Anyway “BMS will always work that way because we want more challenge” would be fine by me, just asking if it’s worth considering
it’s not a gameplay choice, this is the most educated choice we can make
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@Mikyjax said in 4.37.3 AIM120 AQUISITION MODEL:
So this is a pure gameplay choice then?
Since the aim120 is now really nerfed and more realistically modeled compare to earlier do you think that would makes senses to reconsiderate that?There is so much things that I can mess up (and I love it), mistakes that are on me, non respect of the mar, shooting too far, outside of the Circle, bad Sa, bad tactics, bad decision… that when you did “everything correctly” wasting 3 missiles just based on a random loss of lock is a bit frustrating, and that’s only because there is nothing you can do about it. And I’m even talking in STT.
Anyway “BMS will always work that way because we want more challenge” would be fine by me, just asking if it’s worth considering
ARHs in the past were modeled as some kind of holy weapons. (As were all IR missiles before the new IR code.)
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@molnibalage said in 4.37.3 AIM120 AQUISITION MODEL:
@Mikyjax said in 4.37.3 AIM120 AQUISITION MODEL:
So this is a pure gameplay choice then?
Since the aim120 is now really nerfed and more realistically modeled compare to earlier do you think that would makes senses to reconsiderate that?There is so much things that I can mess up (and I love it), mistakes that are on me, non respect of the mar, shooting too far, outside of the Circle, bad Sa, bad tactics, bad decision… that when you did “everything correctly” wasting 3 missiles just based on a random loss of lock is a bit frustrating, and that’s only because there is nothing you can do about it. And I’m even talking in STT.
Anyway “BMS will always work that way because we want more challenge” would be fine by me, just asking if it’s worth considering
ARHs in the past were modeled as some kind of holy weapons. (As were all IR missiles before the new IR code.)
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@Mav-jp '‘First shalt thou take out the Holy Pin. Then shalt thou count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in My sight, shall snuff it.’
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@Carbide said in 4.37.3 AIM120 AQUISITION MODEL:
@Mav-jp '‘First shalt thou take out the Holy Pin. Then shalt thou count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in My sight, shall snuff it.’
Exactly.
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@molnibalage said in 4.37.3 AIM120 AQUISITION MODEL:
- How is modeled the radar scan of the missile? Scan rate (angle sec/bars?) If the FRQ of the radar is known based on the size is is an easy calculation to determine the beamwidth. We can assume 10 GHz, almost every ARH uses the FRQ. Is it / will be modeled the scan?
10 GHz is very common for fighter radars, but it may not be for missile radars.
For instance, Meteors and MICAs use Ku-band radars and, interestingly enough, the AV-8B Tactical Volume stated in 2002 : “With the recent availability of suitable millimeter-wave power-generating components, radar designers are developing extremely small, albeit short-range, radars which take advantage of the atmospheric window at 94 GHz to provide radar capabilities in small packages (i.e., air-to-air missiles, AH-64 longbow).”A bit earlier in the same volume it reads : “As an example, the airborne warning and control system (AWACS) radar operates in the S-band (10 cm). These radio waves are considerably longer than that used by the APG-65 (3 cm), however, AWACS utilizes an antenna which is about 24 feet wide. At the other extreme, an air-to-air missile which operates in the millimeter-wave region (94 GHz) can achieve the same angular resolution with a 3.8 inch antenna as an I-band radar would with a 36-inch antenna.”
So the AMRAAM, or some versions of the AMRAAM, may use a 10 GHz radar, but it’s difficult to conclude without clear evidence.
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Very interesting read here guys regarding the AIM-120C but one thing is bothering me ever since I’ve been flying the F-15C Eagle since the latest update. I know its the same AIM-120C missile but it seems to behave differently to the F-16, I dont know whether its just my imagination but I think it tracks more accurately when you fire it from the F-15C. Has anyone done any testing to see if there’s any noticeable difference? Maybe its due to the radar? I know for a while we were blaming changes to the AIM-120 for missed shots and bogey’s dodging our AIM-120s but now I’m not so sure its the missile but something else. Sorry to go off topic a bit maybe this deserves a separate thread?
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@Kavelenko said in 4.37.3 AIM120 AQUISITION MODEL:
Very interesting read here guys regarding the AIM-120C but one thing is bothering me ever since I’ve been flying the F-15C Eagle since the latest update. I know its the same AIM-120C missile but it seems to behave differently to the F-16, I dont whether its just my imagination but I think it tracks more accurately when you fire it from the F-15C. Has anyone done any testing to see if there’s any noticeable difference?
Strictly idenditcal AIM120 model and code
Maybe its due to the radar? I know for a while we were blaming changes to the AIM-120 for missed shots and bogey’s dodging our AIM-120s
That was before 4.37.3 aquisition update
however, there are still some quirks in guidance model particularly in terminal stage.
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@Kavelenko - and I would expect that. The F-15 has a bigger, better radar…and one can’t really consider the AIM-120 without considering the radar.
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
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@Stevie said in 4.37.3 AIM120 AQUISITION MODEL:
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
If you can’t change the reality, try to change your expectations…
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@Stevie said in 4.37.3 AIM120 AQUISITION MODEL:
@Kavelenko - and I would expect that. The F-15 has a bigger, better radar…and one can’t really consider the AIM-120 without considering the radar.
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
It’s good that you consider things but the reality is that a long as FCR lock is maintain , the relative performance (read SNR of concract) has nearly no impact ( 10% difference max in some extreme conditions on the UV)
At the moment the errors build in for every radars are identical so no difference here either
Overall we shouldn’t see any difference really if FCR lock is maintained
It is true that lock is easier to maintain with f15 than f16 due to more powerful radar
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@Mav-jp said in 4.37.3 AIM120 AQUISITION MODEL:
@Stevie said in 4.37.3 AIM120 AQUISITION MODEL:
@Kavelenko - and I would expect that. The F-15 has a bigger, better radar…and one can’t really consider the AIM-120 without considering the radar.
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
It’s good that you consider things but the reality is that a long as FCR lock is maintain , the relative performance (read SNR of concract) has no impact at all .
It is true that lock is easier to maintain with f15 than f16 due to more powerful radar
100% agree. This way of thinking that if larger = better in every aspect is simply false.
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@TOPOLO said in 4.37.3 AIM120 AQUISITION MODEL:
@Stevie said in 4.37.3 AIM120 AQUISITION MODEL:
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
If you can’t change the reality, try to change your expectations…
Exactly. I’m trying to fit the disparate performance I’m reading about here into the reality of the actual aircraft…after talking to a few RL fighter/Viper drivers I know, I’m finding some of my observations are actually correct.
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@Mav-jp said in 4.37.3 AIM120 AQUISITION MODEL:
@Stevie said in 4.37.3 AIM120 AQUISITION MODEL:
@Kavelenko - and I would expect that. The F-15 has a bigger, better radar…and one can’t really consider the AIM-120 without considering the radar.
…and I too am left to consider that it’s the radar model that is making the new missile model behave worse than I expect…I still say the 4.35 model met my expectations for the missile far better.
It’s good that you consider things but the reality is that a long as FCR lock is maintain , the relative performance (read SNR of concract) has nearly no impact ( 10% difference max in some extreme conditions on the UV)
At the moment the errors build in for every radars are identical so no difference here either
Overall we shouldn’t see any difference really if FCR lock is maintained
It is true that lock is easier to maintain with f15 than f16 due to more powerful radar
Not entirely…it’s FAR more complex than that - and in some cases I may not even need a radar track at all… But all that’s not a topic for discussion here.