AWG-9 velocity gating?

[Naquaii]

You need to keep in mind that the AWG-9 does not have a roll gimbal so when you roll the WCS will still point the antenna using only the elevation and azimuth gimbals. This means that if you roll away from the target when it's already at 45 degrees the antenna will now have to add even more azimuth as in effect your translating some of the elevation into azimuth from the radar's perspective. 

 

To me it looks like this is what's happening in your images. Having the target at 45 degrees and rolling away means you're perilously close to the azimuth gimbal limits. The difference between MLC on/off might be radar seeing something to stop at or not and might be as intended, in STT the radar does not correlate anything, it wants to track a single return and will follow the one it sees.

 

We'll have a look on our side though but this might not be a bug at all.

[Noctrach]

22 hours ago, Naquaii said:

To me it looks like this is what's happening in your images. Having the target at 45 degrees and rolling away means you're perilously close to the azimuth gimbal limits.

I'm rolling away with the target at 0 and rolling back upright with the target held at 45.

If you look in the DDD you see the gimbal limit stays under 50, which should be perfectly fine for a radar with a true limit of 65 degrees right?

That's almost 20 degrees of play horizontally and over 40 degrees vertically... I've hooked targets much further towards the gimbal edges in RWS.

 

The video link I attached shows it in action very clearly. I'll relink here https://streamable.com/76b19f

Here is the same phenomenon, 25 degree offset, Iceman diving but no roll: https://streamable.com/87065u

Targets were alive and flying straight and level, without chaff.

 

It doesn't seem like it's hitting any sort of mechanical limit at all. Just the AWG-9 kinda... giving up?

 

Edited March 14, 2021 by Noctrach

[Noctrach]

@NaquaiiDid some more testing today, I can conclude that the following is true:
The AWG-9 loses PD-STT lock if the sum of your bank angle and ATA exceeds 55

 

So in level flight:

Banking more than 55 degrees with a target directly on the nose (ATA ~0) will break the lock.

Banking more than 25 degrees with a target at ATA 30 will also break the lock.

Banking of any kind with a target at ATA 55 will ofc also break the lock.

 

Any STT guided missile in the air is trashed because the track is considered broken the second the AWG-9 loses the lock.

The AWG-9 will remain in trackhold for 2 minutes when this happens unless manually forced out of it.

Reducing the sum to below 55 within 4 seconds will instantly regain the lock, resulting in two overlapping tracks (broken trackhold + new track from regained STT lock).

 

This issue is reproducible 100% of the time.

 

I understand we're dealing with old tech without a roll gimbal, but this math doesn't check out at all.

Rolling in level flight should translate some of the azimuth onto the elevation gimbal, rather than the other way around.

Edited March 14, 2021 by Noctrach

[Naquaii]

We'll have a look as soon as we can. What version are you using? Open beta or stable and are you using the newest version of them?

[Skysurfer]

Can only second this. This all started happening since TWS-A got introduced. Locks were pretty solid and you could roll, maneuver and keep the target at gimballs fairly easily and reliably, without seeing weird double-tracks etc. 

[Noctrach]

10 hours ago, Naquaii said:

We'll have a look as soon as we can. What version are you using? Open beta or stable and are you using the newest version of them?

Thanks :) I'm running the latest open beta

[Harlikwin]

On 3/9/2021 at 2:50 PM, Naquaii said:

According to our information the AWG-9 does not use velocity gating. It uses range-rate instead which is calculated from track position updates. This is what we've modelled in DCS.

 

I'm inclined to say that the weakness of the AWG-9/AIM-54 combo against fighters was the AWG-9 in TWS, not the missile itself.

 

So, while I agree with this sentiment to a point, however also by saying that you seem to be making the claim that the AIM-54 radar/seeker, which started with the same tech, is smaller/less powerful (both in terms of radar power, but much more to the point any sort of processing) and so in theory should have alot of same problems as the AWG-9 and much less actual capability to solve those problems (i.e. no human on board to help with filtering etc).

On 3/9/2021 at 6:38 PM, Gunslinger22 said:

How does this myth of the Tomcat only being designed around being a bomber interceptor keep getting propagated? It was designed for fleet defence, which entails all threats, including the nimblest of fighters. 

 

Yeah, but for nimble fighters the phoenix wasn't really the best choice. Which is why the Cat was a good dogfighter and carried other weapons.

[Gunslinger22]

3 hours ago, Harlikwin said:

 

So, while I agree with this sentiment to a point, however also by saying that you seem to be making the claim that the AIM-54 radar/seeker, which started with the same tech, is smaller/less powerful (both in terms of radar power, but much more to the point any sort of processing) and so in theory should have alot of same problems as the AWG-9 and much less actual capability to solve those problems (i.e. no human on board to help with filtering etc).

 

Yeah, but for nimble fighters the phoenix wasn't really the best choice. Which is why the Cat was a good dogfighter and carried other weapons.

Yet all known information you can find on the C Phoenix will tell you that it was the missile of choice for nimble fighters, bigger motor and speed = better against a tightly turning opponent.

[Noctrach]

13 hours ago, Harlikwin said:

 

So, while I agree with this sentiment to a point, however also by saying that you seem to be making the claim that the AIM-54 radar/seeker, which started with the same tech, is smaller/less powerful (both in terms of radar power, but much more to the point any sort of processing) and so in theory should have alot of same problems as the AWG-9 and much less actual capability to solve those problems (i.e. no human on board to help with filtering etc).

You have to realise the processing for a missile's radar array emitting a specific band of radiation is of an entirely different order of magnitude than having to process TWS resolution cells at long range. This is already true for the A-version. Provided the C-phoenix was capable of emitting in MPRF, which considering the time period is a very reasonable assumption, you're pitting short-ranged MPRF with digital processing against a long-range Hi/Lo PRF interleaved mode with analog filtering. That's not even a contest.

 

AWG-9 was the first fighter-based TWS radar and used some pretty archaic stuff to realise it. However, its Pulse and PD performance was straight bonkers for the time period. This is why we get to the topic of P-STT/PD-STT as being the primary engagement method against fighters. In this mode, the AWG-9 is no longer the weakest link by any stretch of the imagination.

 

The reason DCS players discount STT as a viable tactic is because there's an expectation that missiles always need to kill and that the only way of accomplishing this is to rely on the fact that most PvP pilots have no training, terrible SA and a whole lot of DCS-isms to contend with. So lobbing ARH in TWS at 40 miles or below is considered "the only option" since it's "silent". Add to that the utterly nonsensical approach to chaff-SARH interaction, the utter lack of other EWAR simulation, and the STT-like stability of TWS in some other modules and it's easy to understand where the misunderstandings come from.

[Lurker]

Wow. First of all I didn't realize that the AWG9 did not have a roll gimbal. Second of all, now that I do realize it, I'm actually wondering how it could hold any lock at all during own-ship maneuvers. 

 

 

Edited March 16, 2021 by Lurker

[Harlikwin]

13 hours ago, Gunslinger22 said:

Yet all known information you can find on the C Phoenix will tell you that it was the missile of choice for nimble fighters, bigger motor and speed = better against a tightly turning opponent.

 

Actually the C AFAIK was designed for improved performance against fighters so no bone to pick there, I mainly wonder about seeker performance, which at a guess might have been aamraam like, though more primitive, given the tech of the day. Which then gets us back to the A with 60's era electronics/filters/seeker components etc.  And yes i know it was used by Iran against fighters, so it "could" do it, but the real question gets back how good it really was or what the real limiations/problems were. 

 

 

3 hours ago, Noctrach said:

You have to realise the processing for a missile's radar array emitting a specific band of radiation is of an entirely different order of magnitude than having to process TWS resolution cells at long range. This is already true for the A-version. Provided the C-phoenix was capable of emitting in MPRF, which considering the time period is a very reasonable assumption, you're pitting short-ranged MPRF with digital processing against a long-range Hi/Lo PRF interleaved mode with analog filtering. That's not even a contest.

 

AWG-9 was the first fighter-based TWS radar and used some pretty archaic stuff to realise it. However, its Pulse and PD performance was straight bonkers for the time period. This is why we get to the topic of P-STT/PD-STT as being the primary engagement method against fighters. In this mode, the AWG-9 is no longer the weakest link by any stretch of the imagination.

 

The reason DCS players discount STT as a viable tactic is because there's an expectation that missiles always need to kill and that the only way of accomplishing this is to rely on the fact that most PvP pilots have no training, terrible SA and a whole lot of DCS-isms to contend with. So lobbing ARH in TWS at 40 miles or below is considered "the only option" since it's "silent". Add to that the utterly nonsensical approach to chaff-SARH interaction, the utter lack of other EWAR simulation, and the STT-like stability of TWS in some other modules and it's easy to understand where the misunderstandings come from.

 

Yeah I'm pretty much always talking about the A model when I say phoenix. And yes I totally agree the C is different beast alltogether. 

 

And yes, a big part of the issue are DCSisms. I wouldn't be the least bit surprised if many of the Iran kills with the A were STT kills that just weren't detected by the iraqi fighters/fighter bombers early on. The iran cat book is a bit light on most of those details, though IIRC it does specifically mention TWS being used as well. But most of the long range kills, targets didn't even try to evade or maneuver. Which is a VERY different kettle of fish compared to DCS PVP use. 

 

Hopefully the new EW model will evolve into something vaguely realistic, though TBH given the rather "quasi" realistic "half baked" implementation on the hornet doesn't give me much hope in that regard.

 

Edited March 16, 2021 by Harlikwin

[AH_Solid_Snake]

It is slightly odd that you think A when talking Phoenix, considering the C model specifically replaced the A in 1987, so they are fairly well 50/50 for the F-14s lifespan and DCS has a more modern the better kind of bent.

 

A couple of things I would note is all the tests in the late 70s that became (in)famous were the A model and it was designed to intercept cruise missiles as much as bombers. It’s only big disadvantage against fighters is cost, at 1 million per missile that’s a whole lot of dollars when a Sparrow at 1/3 of the cost or less is just as good against older MiGs. 
 

A lot of assumptions get made about “old” analog technology being crap but the simple truth is like any machine if it’s well maintained and used within its parameters the AIM54A is lethal, digital tech is far easier to reprogram and the integrated circuit is far more reliable, but the earliest “computers” such as fire control computers for battleships are very very good at what they were designed for without a digital signal in sight.

 

The Phoenix is always going to have a huge payload and a massive rocket motor, giving it a lot of speed to pull Gs, even as we move onto the C/ECCM sealed models there wasn’t much talk around needing improvements to guidance or range etc, it was about ensuring that Iran or more likely Russia having reverse engineered the A model would be unable to jam the new C model, improved reliability and not requiring the liquid cooling loop are also not inconsiderable benefits.

[Harlikwin]

22 hours ago, AH_Solid_Snake said:

It is slightly odd that you think A when talking Phoenix, considering the C model specifically replaced the A in 1987, so they are fairly well 50/50 for the F-14s lifespan and DCS has a more modern the better kind of bent.

 

A couple of things I would note is all the tests in the late 70s that became (in)famous were the A model and it was designed to intercept cruise missiles as much as bombers. It’s only big disadvantage against fighters is cost, at 1 million per missile that’s a whole lot of dollars when a Sparrow at 1/3 of the cost or less is just as good against older MiGs. 
 

A lot of assumptions get made about “old” analog technology being crap but the simple truth is like any machine if it’s well maintained and used within its parameters the AIM54A is lethal, digital tech is far easier to reprogram and the integrated circuit is far more reliable, but the earliest “computers” such as fire control computers for battleships are very very good at what they were designed for without a digital signal in sight.

 

The Phoenix is always going to have a huge payload and a massive rocket motor, giving it a lot of speed to pull Gs, even as we move onto the C/ECCM sealed models there wasn’t much talk around needing improvements to guidance or range etc, it was about ensuring that Iran or more likely Russia having reverse engineered the A model would be unable to jam the new C model, improved reliability and not requiring the liquid cooling loop are also not inconsiderable benefits.

 

Not odd at all really. The A was the only relevant model to the Cold War, which is my main interest. Its also the only model of Phoenix that was actually used in combat to my knowledge. The C never was so we have no idea how good or bad it was aside from a few "hints" from nebulous sources. 

 

Yeah and the cruise missile intercept is against a high speed target (big doppler shift) that isn't maneuvering. Or in the case of a bomber a thing with a massive RCS that also isn't maneuvering much. That isn't to say the phoenix couldn't be used against maneuvering targets I'm familiar with the one publicly known test case, and I'm sure at least a few iraqi migs might have tried to dodge them later on when fitted with a decent RWR. Also, I'm familiar with the G rating of the missile, which wasn't that great by missile standards of the day, with both the Sparrow and Sidewinder being MUCH higher rated. But alot of that depends on the kinematics of the shot. 

 

I am glad that HB finally has upgraded the missile to miss at long if lock is lost. Which as previously stated was probably a large weakness of it. But again, even late 70's sparrows with improved seeker heads and frankly a much "simpler" problem to solve still didn't have great overall pK's (like ~50% for late model M's in the gulf). So this idea that somehow the A model with older electronics, and harder set of problems to solve was somehow magically better than that I find a bit difficult to swallow.

 

Edited March 17, 2021 by Harlikwin

[captain_dalan]

On 3/14/2021 at 7:34 PM, Noctrach said:

@NaquaiiDid some more testing today, I can conclude that the following is true:
The AWG-9 loses PD-STT lock if the sum of your bank angle and ATA exceeds 55

 

 

 

 

On 3/14/2021 at 11:28 PM, Skysurfer said:

Can only second this. This all started happening since TWS-A got introduced. Locks were pretty solid and you could roll, maneuver and keep the target at gimballs fairly easily and reliably, without seeing weird double-tracks etc. 

I was thinking i'm the only one that gets worse performance from the radar in STT then in TWS, and was about to ask you guys, how do you manage to retain any tracks at all when i found this topic. Good find guys, props to you!!!

Edited March 17, 2021 by captain_dalan

[Lurker]

9 hours ago, captain_dalan said:

 

I was thinking i'm the only one that gets worse performance from the radar in STT then in TWS, and was about to ask you guys, how do you manage to retain any tracks at all when i found this topic. Good find guys, props to you!!!

 

 

I know that Naquaii responded and everything but maybe Noctrach should open a topic in the bug section just in case? 

[TotenDead]

Are we going to have poor tracking capabiities of AWG-9 when used in look down shoot down situations?

[Harlikwin]

5 hours ago, TotenDead said:

Are we going to have poor tracking capabiities of AWG-9 when used in look down shoot down situations?

 

I think this is already a thing to some extent. I have a hard time with phoneixes connecting in look down, its better in look up. 

 

[Skysurfer]

6 hours ago, TotenDead said:

Are we going to have poor tracking capabiities of AWG-9 when used in look down shoot down situations?

 

Which, should not be the case? Read Victory205's take on it in another thread.

[Naquaii]

On 3/15/2021 at 11:13 PM, Harlikwin said:

 

So, while I agree with this sentiment to a point, however also by saying that you seem to be making the claim that the AIM-54 radar/seeker, which started with the same tech, is smaller/less powerful (both in terms of radar power, but much more to the point any sort of processing) and so in theory should have alot of same problems as the AWG-9 and much less actual capability to solve those problems (i.e. no human on board to help with filtering etc).

 

Yeah, but for nimble fighters the phoenix wasn't really the best choice. Which is why the Cat was a good dogfighter and carried other weapons.

 

As have been mentioned after your post, comparing the missile seeker to the AWG-9 is an unfair comparison for the AWG-9. The AIM-54 seeker has an entirely different job to do and the AWG-9 holds its hand for the majority of the engagement so to speak. When the seekerhead in the AIM-54 has to take over and do it's job it's always at fairly short range and already pointed at the correct target (unless ACM) and even then it can fall back to look for pointers from the AWG-9. That the seeker would be bad at that job is not something I've ever seen mentioned. Being bad against much more modern ECMs is a given but also not really relevant in this discussion as nearly no information is available publicly and not modelled in DCS anyway.

 

As for the missile being bad against fighters that's a point of view I've seen a lot but I've never ever seen anyone back that theory up with anything but speculation, hearsay or other vague evidence. Our information about the AIM-54 does not agree, in fact it kinda points towards it being perfectly fine against fighters as well.

 

Everyone is of course welcome and encouraged to have their own point of view but without anything resembling actual facts it's nothing we'll take into account or use as a reason for eventual changes to the module.

[Harlikwin]

1 hour ago, Naquaii said:

 

As have been mentioned after your post, comparing the missile seeker to the AWG-9 is an unfair comparison for the AWG-9. The AIM-54 seeker has an entirely different job to do and the AWG-9 holds its hand for the majority of the engagement so to speak. When the seekerhead in the AIM-54 has to take over and do it's job it's always at fairly short range and already pointed at the correct target (unless ACM) and even then it can fall back to look for pointers from the AWG-9. That the seeker would be bad at that job is not something I've ever seen mentioned. Being bad against much more modern ECMs is a given but also not really relevant in this discussion as nearly no information is available publicly and not modelled in DCS anyway.

 

As for the missile being bad against fighters that's a point of view I've seen a lot but I've never ever seen anyone back that theory up with anything but speculation, hearsay or other vague evidence. Our information about the AIM-54 does not agree, in fact it kinda points towards it being perfectly fine against fighters as well.

 

Everyone is of course welcome and encouraged to have their own point of view but without anything resembling actual facts it's nothing we'll take into account or use as a reason for eventual changes to the module.

 

Well I agree with you on many parts of what you say, I'm just trying to apply some logic to the situation. 

 

For a late model 80's era Aim-7m seeker which were used in combat the pK was something like 50% or bit higher IIRC. Now of course theres a bunch variables there on why they hit or didn't. But lets say its being guided by a powerful (relative to a phoneix radar) with excellent performance (I.e. lets say for the sake of argument the APG63 is a better radar) at not much further ranges (20nm vs 10nm for the phoenix). So should we assume that in that same set of circumstances that the phoenix A would do better, and if so why? I realize its not entirely apples to apples but I'm really trying to wrap my head around why the phoenixA would be better in that set of circumstances strictly from a guidance standpoint? Cuz  as I see it, its got a way less powerfull radar to illuminate the target, and assuming it even has a monopulse seeker (don't know if it does one way or another, they weren't fitted to Aim-7s till much later). Its guidance logic and guidance laws are also likely going to be less refined than missile seeker built 20+ years later. 

 

As for better ECM, well, supposedly its coming right?

 

Edited March 18, 2021 by Harlikwin

[Skysurfer]

11 minutes ago, Harlikwin said:

 

Well I agree with you on many parts of what you say, I'm just trying to apply some logic to the situation. 

 

For a late model 80's era Aim-7m seeker which were used in combat the pK was something like 50% or bit higher IIRC. Now of course theres a bunch variables there on why they hit or didn't. But lets say its being guided by a powerful (relative to a phoneix radar) with excellent performance (I.e. lets say for the sake of argument the APG63 is a better radar) at not much further ranges (20nm vs 10nm for the phoenix). So should we assume that in that same set of circumstances that the phoenix A would do better, and if so why? I realize its not entirely apples to apples but I'm really trying to wrap my head around why the phoenixA would be better in that set of circumstances strictly from a guidance standpoint? Cuz  as I see it, its got a way less powerfull radar to illuminate the target, and assuming it even has a monopulse seeker (don't know if it does one way or another, they weren't fitted to Aim-7s till much later). Its guidance logic and guidance laws are also likely going to be less refined than missile seeker built 20+ years later. 

 

As for better ECM, well, supposedly its coming right?

 

 

 

Simply put the Phoenix isn't a Sparrow and you can't compare the two. Also, where do you get the 50% Pk claim for the later 7M? Source please.

[Harlikwin]

Just now, Skysurfer said:

 

Simply put the Phoenix isn't a Sparrow and you can't compare the two. Also, where do you get the 50% Pk claim for the later 7M? Source please.

 

Its not really that simple, you can make some comparisons. Both systems are similar enough in terms of how radar guided missiles work, sure the phoneix has its own radar for tgt illumination at close(er) range but that causes other problems than SARH stuff has to contend with too. 

 

I don't have the source of the top of my head, I'll see if I can dig it out later, but it was around that for the gulf war sparrow shots if memory serves. 

 

 

[near_blind]

10 minutes ago, Skysurfer said:

Also, where do you get the 50% Pk claim for the later 7M? Source please.

 

https://web.archive.org/web/20130720010705/http://www.dtic.mil/ndia/2006psa_winter_roundtable/watts.pdf#

[Harlikwin]

6 minutes ago, near_blind said:

 

https://web.archive.org/web/20130720010705/http://www.dtic.mil/ndia/2006psa_winter_roundtable/watts.pdf#

 

Thanks, yeah so memory being what it is kills were high 50's though actual hits were 68%. 

[dundun92]

One thing to note with the sparrow numbers is that a lot of misses were due to motor issues, e.g, motor not lighting, or the sparrow getting hung on the Pylon. IK thats all included in Pk, but it should be noted that a  lot of the misses were not due to the seeker/guidance/tracking.

 

Also, even considering all that, im not sure why people are so hung up on Pk. There are simply too many variables for Pk to really be of any use unless you have the specifics of every engagement. For example, if your trying to run a CAP and you simply need to keep the bad guys away, not kill them, you may take longer ranged, lower Pk posturing shots. While the Pk achieved in this scenario may be close to 0%, it doesn't mean the missile is bad; all it means is that the bandit defended well, and that the missiles did their job of keeping people away. The point is, saying "The sparrow had 50% Pk in combat" is fine, but its not something you can use to say "why would the AIM-54 do better". Unless you can prove that the 50% Pk was actually due to seeker/guidance/tracking issues, and that these same weaknesses were present in the AIM-54, theres no real basis for comparison.