AIM-54 Changes / new API fixes are live in today's patch

[GGTharos]

 

Genuine curiosity:

If some RWR systems can detect the changes in the signal that occur when a missile is launched (such as the command data being "piggy-backed" with the tracking pulses), what is stopping the weapon control system from transmitting the command data at all times? Is it a design choice? Or is does the signal transmitted distinguished by additional data packets, like missile position or such?

 

Yes, it is a design choice. I can only guess at the reasons (ECM/ECCM, conserving processor capacity, easing cooling requirements etc) - there's no signal piggy-backing, you're injecting it in the interval between the radar pulses. And yes, each time one of those DL pulses goes out, it contains some information - can be position, vector, closure ... whatever you can't fit into one pulse you send in the other, so it's possible that you don't get the entire message out in a single pulse.

 

I don't know what the illumination/guidance signal that's injected does, but I imagine it has a to do with ECCM capability.

[Triggerjo23]

Hang on let me get this straight, Crash is arguing that not only should the AIM54 not give any launch warning when fired in STT mode, but that it guides in the same way as it would when fired in TWS mode? Yeah, that doesn't sound right does it?

 

What would you do if fired on with a missile warning from over 50 miles? There are long range fox ones which guide in with no missile warning. The R-33 is designed like this and it guides over 160 miles with no warning until it reaches a certain stage and then is guided fuly using the radar. Why would the Phoenix which was built at the same time and is more advanced not have this ability? Nothing sounds wrong about it, it is just that there is confusion over how an AIM-7 tracks in SARH and how a Phoenix tracks in SARH/DL.

[Triggerjo23]

 

The one that describes how Phoenix works, and no, I cannot. But I'm sure HB has it ;)

 

If you can not supply us with references then you have to understand that all of this is speculation. You seem to be thinking that the Phoenix must track like a fox 1 when fired in SARH/DL except TWS uses SARH/DL too. Without references then we won't get anywhere. Also, if you don't have the manual then how did you come across the information?

[captain_dalan]

 

Yes, it is a design choice. I can only guess at the reasons (ECM/ECCM, conserving processor capacity, easing cooling requirements etc) - there's no signal piggy-backing, you're injecting it in the interval between the radar pulses. And yes, each time one of those DL pulses goes out, it contains some information - can be position, vector, closure ... whatever you can't fit into one pulse you send in the other, so it's possible that you don't get the entire message out in a single pulse.

 

I don't know what the illumination/guidance signal that's injected does, but I imagine it has a to do with ECCM capability.

 

I think i get what you're saying. So essentially your are emitting separate pulses, illumination ones and data-transfer ones. This would explain the extra "chirp" on the RWR mentioned in that interview. And if enough processing power is available (and recorded data on WCS-radar performance too) i can see how this could be used to provide launch warnings.

 

What is stopping the data from being piggy backed? Lack of bandwidth?

[Triggerjo23]

 

The guidance in in the name: SARH. The H stands for homing. It's not any type of command guidance, it is homing.

 

And this aside, the command link would trigger the RWR just like it does for SAMS.

 

Homing means homing in on the guidence signal wether it be radar or data link. Also, the vast majority of SAMs are fox 1's which again does not justify what you are saying about the Phoenix when in SARH/DL. It saying Homing does not mean a missile warning as again TWS uses SARH/DL too and TWS does not give a missile warning.

[GGTharos]

 

If you can not supply us with references then you have to understand that all of this is speculation. You seem to be thinking that the Phoenix must track like a fox 1 when fired in SARH/DL except TWS uses SARH/DL too. Without references then we won't get anywhere. Also, if you don't have the manual then how did you come across the information?

 

Sure, one such document is NAVAIR 01-F14AAA-1A.

 

And yes, the Phoenix tracks like a fox 1 when launched in PDSTT, the radar doesn't send the missile active command.

 

There are 5 modes:

 

SD/A (TWS), 'Sample Data/Active' with 3 guidance phases; inertial, mid-course and terminal active. The WCS steers the seeker towards the desired target, and the Phoenix homes in on it like a fox1 during its mid-course flight but with a fixed guidance constant. It will only get 1-2 updates every 2 seconds this way.

 

Continuous Semiactive - WCS operating in PDSTT, PDRSL or HI-JAT. There are here guidance phases here too: Inertial, mid-course and SARH terminal homing. Mid-course is as above but with more frequent command/update messages (About 4/sec).

 

Normal Active: As both of the above, but missile is commanded to go active in the first data message. This happens when the target is inside 10nm.

If the PH ACT switch is selected the missile will revert back to SD/A or CSA as above to get instructions if it cannot detect a target return. This mode skips mid-course guidance with all attendant disadvantages for long-range shots.

 

ACM Active: There is no support from the WCS here after launch. It's commanded active before it launches (that doesn't mean it goes active on the rail, it's a stored command to go active ASAP, 0.18sec after launch which is also shortened from 3 sec to 1 sec in some cases). If there is no sensor track, this allow a maddog launch.

 

ECM Passive: Can be used to passively attack ECM targets that are emitting in the seeker's frequency spectrum. This is used with any of the above modes. Basically HoJ.

[GGTharos]

Homing means homing in on the guidence signal wether it be radar or data link. Also, the vast majority of SAMs are fox 1's which again does not justify what you are saying about the Phoenix when in SARH/DL. It saying Homing does not mean a missile warning as again TWS uses SARH/DL too and TWS does not give a missile warning.

 

Homing means homing on the energy reflected or radiated by the target. It does not mean commanding the missile to fly in that direction by the weapon system or sending a detonation signal like some tried to suggest. You cannot home in on a data-link signal, the data-link helps the missile get into position to begin homing.

 

I did not say anywhere that it would provide a warning in the RWR in TWS. I said you COULD program your RWR to give you that knowledge, but this is a customer option.

 

I don't know why you're bringing SAMs into this, SAMs have more options for their guidance shenanigans, and a bunch of them are command-guided and not homing.

[Triggerjo23]

 

SD/A (TWS), 'Sample Data/Active' with 3 guidance phases; inertial, mid-course and terminal active. The WCS steers the seeker towards the desired target, and the Phoenix homes in on it like a fox1 during its mid-course flight but with a fixed guidance constant. It will only get 1-2 updates every 2 seconds this way.

 

Continuous Semiactive - WCS operating in PDSTT, PDRSL or HI-JAT. There are here guidance phases here too: Inertial, mid-course and SARH terminal homing. Mid-course is as above but with more frequent command/update messages (About 4/sec).

 

 

 

 

"I don't know why you're bringing SAMs into this, SAMs have more options for their guidance shenanigans, and a bunch of them are command-guided and not homing."

 

Ok, you just confirmed what I thought. The missile does not give a warning in PD-STT SARH/DL. Thanks very much.

 

I brought SAMs into it becuase you brought SAMs into it. You were the first one to bring them up. ;p

[Triggerjo23]

 

Homing means homing on the energy reflected or radiated by the target. It does not mean commanding the missile to fly in that direction by the weapon system or sending a detonation signal like some tried to suggest. You cannot home in on a data-link signal, the data-link helps the missile get into position to begin homing.

 

I did not say anywhere that it would provide a warning in the RWR in TWS. I said you COULD program your RWR to give you that knowledge, but this is a customer option.

 

 

You are not homing in on the DL signal you are homing in on the information it gives you to home in on.

 

RWR does not sense DL, if it was set off via DL then it would go off every time you fire a missile too. Also, everytime you get signal from an AWACS or other friendly aircraft. Also, Heatblur say SARH/DL all the way to target.

[GGTharos]

 

Ok, you just confirmed what I thought. The missile does not give a warning in PD-STT SARH/DL. Thanks very much.

 

I brought SAMs into it becuase you brought SAMs into it. You were the first one to bring them up. ;p

 

There's a detectable signal in there which does not exist when the missile is not in flight. The only case where that signal does not exist is AND a missile is launched is ACM, but the missile itself is active in this case.

[GGTharos]

You are not homing in on the DL signal you are homing in on the information it gives you to home in on.

 

No, because that literally is not homing. What you are describing is command guidance. Homing means the missile independently detects and tracks the target, it homes in on it. In the case of Phoenix the DL is there to get it to a point where it can go to terminal homing.

 

RWR does not sense DL, if it was set off via DL then it would go off every time you fire a missile too.

 

Of course it does, exactly the same way the missile does. STT confirms that the offending F-14 is going to attack you, the injection of the DL signal confirms that it IS attacking you because that signal is generated when a missile is launched.

 

Also, everytime you get signal from an AWACS or other friendly aircraft.

 

The M-Link is transmitted by the radar antenna on the same frequency as the STT signal, inserted between the STT pulses.

You RWR has no real reason to warn you about any other such M-Link signals if they are not combined with this STT transmission since it cannot confirm that this is targetting your specific aircraft.

 

 

STT = 'lock'

STT + DL = 'launch'

 

A data-link from the AWACS is transmitted by a completely different radio, on completely different frequency (In the MHz range, as opposed the 8-12GHz range for an AI radar and the missile's seeker) and not at all associated with the weapon or the radar guiding it. There is no reason for the RWR to trip on it, if indeed it even picks up that particular frequency.

 

Also, Heatblur say SARH/DL all the way to target.

 

And? What are you addressing here? The DL will be transmitted until the time-out period.

[Triggerjo23]

 

Sure, one such document is NAVAIR 01-F14AAA-1A.

 

This manual is for the F14A also and I can not find it anywere, do you have a link? And one for the B?

[Triggerjo23]

 

No, because that literally is not homing. What you are describing is command guidance. Homing means the missile independently detects and tracks the target, it homes in on it. In the case of Phoenix the DL is there to get it to a point where it can go to terminal homing.

 

Of course it does, exactly the same way the missile does. STT confirms that the offending F-14 is going to attack you, the injection of the DL signal confirms that it IS attacking you because that signal is generated when a missile is launched.

 

The M-Link is transmitted by the radar antenna on the same frequency as the STT signal, inserted between the STT pulses.

You RWR has no real reason to warn you about any other such M-Link signals if they are not combined with this STT transmission since it cannot confirm that this is targetting your specific aircraft.

 

STT = 'lock'

STT + DL = 'launch'

 

A data-link from the AWACS is transmitted by a completely different radio, on completely different frequency (In the MHz range, as opposed the 8-12GHz range for an AI radar and the missile's seeker) and not at all associated with the weapon or the radar guiding it. There is no reason for the RWR to trip on it, if indeed it even picks up that particular frequency.

 

And? What are you addressing here? The DL will be transmitted until the time-out period.

 

TWS Transimits Data link in the same manner as PD-STT so you will get that information and it is important to tell the pilot about it if you can sense it via an RWR.

 

So,

STT = 'lock'

STT + DL = 'launch'

 

Would also equal

 

TWS= Jet on the RWR Scope.

TWS Jet on scope + DL signal= Launch but maybe not at you so warn other pilots in the area.

 

This is not the case though is it.

[GGTharos]

 

TWS Transimits Data link in the same manner as PD-STT so you will get that information and it is important to tell the pilot about it if you can sense it via an RWR.

 

So,

STT = 'lock'

STT + DL = 'launch'

 

Would also equal

 

TWS= Jet on the RWR Scope.

TWS Jet on scope + DL signal= Launch but maybe not at you so warn other pilots in the area.

 

This is not the case though is it.

 

So what? Why do you assume it means anything other than a choice by the customer to program it that way? So you know all the 10 aircraft in front of you launched. And? How does this affect you? You already knew they were going to do this, and you can't get any extra information such as who they are targeting specifically. Your tactics have taken all the intel you have into account with respect to their tactics, their weapon system, desired launch ranges etc.

 

Sure, there is some information you could extract (maybe some contacts are not launching) but it may not be useful either if it's a close gaggle, you can't tell who exactly did what, just that some did or didn't, if that (RWRs have a limit of displayed symbols) - this goes back to tactics etc.

 

So, how do you program priorities of which symbols to display and what warnings to give? STT+DL is pretty simple and pretty obvious. Other conditions may not be so simple.

[GGTharos]

 

This manual is for the F14A also and I can not find it anywere, do you have a link? And one for the B?

 

You won't be able to find it ... maybe in the future.

[Crash2]

 

So the argument continues about why can't RWR pick up on DL signals associated with a launch of a Phoenix in PD-STT. I will point out that from my understanding of the changes, P-STT should still act as it did before with a launch warning given once the missile has left the rails. I was never saying that all STT modes would allow the missile to track without a missile launch warning, but as PD-STT uses SARH/DL it will not give an RWR launch warning.

 

Now back to why RWR's do not detect a datalink signal transmitted between missile and launching aircraft. This is mostly down to the principle of false alarms, make a sensor too sensitive and too many false alarms decreases pilots trust on the very device meant to keep them alive. While RWR can detect long range EWR systems and track radar's signatures all of these signals must be processed and analyzed by the computer to determine the threat type. And as I do not have access to documentation able to help me understand how the datalink between missile and aircraft works there are a few things I do know about radar and radio's in general.

 

Now from what Heatblur have provided we know two things one that PD-STT when launch above 10nm uses the same radar mode as TWS as has been stated in the changes at the beginning of this post. Second we know that TWS does not give a launch warning due in part to the function and design of TWS. To be able to track and launch on multiple targets at once. This the radar system must do by itself with only radar sweeps every few seconds to update the pathing information on the target. Now we take that same radar mode and we give it constant radar information updates and we get the new PD-STT.

 

Now the radar detection systems on the Tomcat are not the newest systems in the game, in fact that honor goes to the JF-17 and that system has the same limitations it cannot detect a TWS launch. Even if the receivers on the target were able to pick up the datalink signal they would also have to know what it is and decipher it as a missile datalink signal, which is more than likely encrypted and may operate on different frequencies to avoid collisions with other aircraft. This alone could make detection and deciphering much harder if not impossible in the time of a missile flight.

 

Next problem the false alarm problem. The RWR system obviously has a threshold for how often a radar sweep is detected and how much energy is being directed at the aircraft. Too low and you perceive a threat which is not there and start a shooting war when no hostile action was actually taken. Or worse the pilots don’t trust the instrument and when the threat is real don’t react. These are possibilities which designers of these systems must take into account when making them so as to prevent the false alarm problem, better known as crying wolf.

 

Now you maybe saying but the system on the A-10 alerts pilots to every launch, yes it does and do you know how many times pilots in DCS have popped flares and chaff due to a friendly Maverick launch. Now you maybe saying well that isn’t so bad better to be on your toes than not. Until you get 5 in a row and none are a real threat so when the 6^th comes along you don’t think it is real and bang, dead. In the long run better to have a system which is reliable and indicates accurate and true threats than false ones.

 

[Triggerjo23]

 

So what? Why do you assume it means anything other than a choice by the customer to program it that way? So you know all the 10 aircraft in front of you launched. And? How does this affect you? You already knew they were going to do this, and you can't get any extra information such as who they are targeting specifically. Your tactics have taken all the intel you have into account with respect to their tactics, their weapon system, desired launch ranges etc.

 

Sure, there is some information you could extract (maybe some contacts are not launching) but it may not be useful either if it's a close gaggle, you can't tell who exactly did what, just that some did or didn't, if that (RWRs have a limit of displayed symbols) - this goes back to tactics etc.

 

So, how do you program priorities of which symbols to display and what warnings to give? STT+DL is pretty simple and pretty obvious. Other conditions may not be so simple.

 

I am not buying it. If you could sense DL via the RWR you would most certainly tell the pilot about it. That is extremely important information. I think you are just speculatiing to be honest. I don't know whether there should or should not be a warning which is why I asked the question in the first place but what you are saying does not seem to confirm your suspicions to me. If the RWR gets a missile warning then it simply would not be due to sensing DL as that seems absurd but it would be becuase the radar is chirping to prevent ECM from overwhelming the tracking. I doubt this would be the case though as PD-STT launches are useful over long ranges which would not be the case with a missile warning.

 

Considering also that even the russians had similar missile in the same era which would not give a missile warning up to a certain point when guided in STT as they were fox 1's. I doubt very much that this was an oversight for the US especialy considering the missiles ultimately had the same function. The Mig-31 for example does this and what I have read from others the Phoenix in PD-STT (SARH/DL) does the same thing.

 

Again, I am not saying you are wrong at all. Just that you are not making much sense when talking about the RWR using DL to sense a launch and other are tellingme information to the contrary. So basicaly without the manual or Heatblur actualy saying you or I are right then we won't have the answer.

[Triggerjo23]

 

You won't be able to find it ... maybe in the future.

 

This does not help either though does it. You have access to it? Are you an F14 Pilot? It is not classified is it becuase you can buy phisical copies, so why not quote and link the exact segment which confirms what you are saying?

This is why it sounds like speculation from everyone.

[Skysurfer]

Now all of this also depends on the RWR and how modern and pre-programmed it is. Obviously in DCS all or most RWR's react the same way to the same types of emmiters and threats. Regarding the STT discussion, in the Viper you have STT an SAM locks as well, which dont give any aircraft a launch warning until the missile goes active. Same with the Hornet last time I checked. Thus, since DCS RWR's are very simplified there needs to be an uniform agreement how fox 3's and fox 1's work under STT.

 

From the unclass documentation I could find (see below)

 

Obviously there are no mentions of extra injected signals or any changes to the STT signal after missile launch. To my understanding the 54 simply homes onto the PD-STT return. And even if there are extra injected signals or a change in frequency, the specifics are most likely still classified and it is also not clear whether the RWR systems we have in the game are able to detect those or even make sense of them, which is where the decision has to be made whether it is supposed to give a launch warning to all aircraft, including the oldest ones or not. Surely something like a pre-tuned rudimentary SPO-10 or 15 wont be able to tell. The Phoenix is also not a sparrow or R-27 where either monopulse or CW illum. are used.

[Triggerjo23]

Now all of this also depends on the RWR and how modern and pre-programmed it is. Obviously in DCS all or most RWR's react the same way to the same types of emmiters and threats. Regarding the STT discussion, in the Viper you have STT an SAM locks as well, which dont give any aircraft a launch warning until the missile goes active. Same with the Hornet last time I checked. Thus, since DCS RWR's are very simplified there needs to be an uniform agreement how fox 3's and fox 1's work under STT.

 

From the unclass documentation I could find (see below)

 

Obviously there are no mentions of extra injected signals or any changes to the STT signal after missile launch. To my understanding the 54 simply homes onto the PD-STT return. And even if there are extra injected signals or a change in frequency, the specifics are most likely still classified and it is also not clear whether the RWR systems we have in the game are able to detect those or even make sense of them, which is where the decision has to be made whether it is supposed to give a launch warning to all aircraft, including the oldest ones or not. Surely something like a pre-tuned rudimentary SPO-10 or 15 wont be able to tell. The Phoenix is also not a sparrow or R-27 where either monopulse or CW illum. are used.

 

Yes, so basicaly if the target does not get a missile warning when a Phoenix is fired in PD-STT (SARH/DL) then it is the F14's equivilant to the F16's SAM and STT.

[Skysurfer]

 

Yes, so basicaly if the target does not get a missile warning when a Phoenix is fired in PD-STT (SARH/DL) then it is the F14's equivilant to the F16's SAM and STT.

 

No it's two completely different radars. I was refering to DCS and how their STT-fox3 model works. Because it seems like the API does not allow to have a hybrid of fox-1 and 3 etc. this has also changed several times over the years. All I am trying to get at is how the PD-STT launched Phoenix should behave. Should it behave purely like an oversized AIM-7M/R-27R or be a new type where you just receive a spike untill impact? Because so far I have not found sufficient and believable evidence that the latter should not be the case and simply fully trust Heatblur to implement this correctly into the game.

[Triggerjo23]

 

No it's two completely different radars. I was refering to DCS and how their STT-fox3 model works. Because it seems like the API does not allow to have a hybrid of fox-1 and 3 etc. this has also changed several times over the years. All I am trying to get at is how the PD-STT launched Phoenix should behave. Should it behave purely like an oversized AIM-7M/R-27R or be a new type where you just receive a spike untill impact? Because so far I have not found sufficient and believable evidence that the latter should not be the case and simply fully trust Heatblur to implement this correctly into the game.

 

I know they are diferent radars, which is why I said "Equivilant". SAM does not give a missile warning and niether does PD-STT (SARH/DL) meaning that they effectively function the same way for at least a large portion of the missiles flight time. Meaning that the missile can track on an STT lock and not give a warning. "Equivilant", not the exact same but similar behaviour for both.

[Triggerjo23]

All I am trying to get at is how the PD-STT launched Phoenix should behave. Should it behave purely like an oversized AIM-7M/R-27R or be a new type where you just receive a spike untill impact? Because so far I have not found sufficient and believable evidence that the latter should not be the case and simply fully trust Heatblur to implement this correctly into the game.

 

We are on the same page with this I asure you. This is what I want to know. There is no reason from what I understand that would make the missile just a giant AIM-7 and have to track the same way but others are saying to the contrary. Also, all the information they are quoting to justify what they are saying either makes no sense or is only relevent to the AIM-7 which also makes no sense.

[GGTharos]

No it's two completely different radars. I was refering to DCS and how their STT-fox3 model works. Because it seems like the API does not allow to have a hybrid of fox-1 and 3 etc. this has also changed several times over the years. All I am trying to get at is how the PD-STT launched Phoenix should behave. Should it behave purely like an oversized AIM-7M/R-27R or be a new type where you just receive a spike untill impact? Because so far I have not found sufficient and believable evidence that the latter should not be the case and simply fully trust Heatblur to implement this correctly into the game.

 

In terms of the RWR yes, you should be getting a launch warning from start to finish. In terms of flight path and guidance, same as SD/A but with much faster and accurate update rate, and of course SARH for terminal instead of ARH.

 

AIM-7F/M don't have the loft profile or the DL, but there is some injected signal for guidance, so there's the difference.

[Skysurfer]

 

In terms of the RWR yes, you should be getting a launch warning from start to finish. In terms of flight path and guidance, same as SD/A but with much faster and accurate update rate, and of course SARH for terminal instead of ARH.

 

AIM-7F/M don't have the loft profile or the DL, but there is some injected signal for guidance, so there's the difference.

 

Both the 7M/H and R-27R/ER have DL coupled INS for the initial phase, the MH also lofts. But yeah fair enough, I think we can end this discussion on this as this is getting nowhere without some clear cut technical documentation which is obviously still class.