P-STT not working in singleplayer?

So I'm noticing my AIM-7s in P-STT mode being consistently decoyed by AI jets in singleplayer in scenarios where this should be practically impossible.

I'm firing between 7 and 12 miles in a look-up scenario against clear sky, yet despite the lock never breaking... almost all of my missiles will go for bundles of chaff. Some never even start tracking and just go for chaff off the rails.

I'm even seeing 5 mile shots on hot aspect targets jink off-target and go for chaff instead.

Is Jester doing something wrong with the radar? Is P-STT/CW illumination not implemented yet? Is SARH missile guidance just utterly broken?

Am I missing something?

Hey, thank you for your report. A couple remarks on that from my side: first of all I think you are demanding a bit too much from your aim7s. In DCS one has to get acquainted to shorter ranges. The Aim7 really is effective around 5nm range - that is on targets that are highly aware of you and meneuvering hard. The AI unfortunately is omniscient often enough in these scenarios, and depending on the altitude difference the aim7 probably not necessarily only falls for their chaff, but also runs out of energy. Chaff is supposed to spook it, and it does. Which is fine. What isn't fine is the AI always chaffing perfectly etc, etc - which is out of our reach (as missile guidance in general).

But PSTT works fine, and SARH in general, too. The aim7 also can have a much longer reach, that is in look down situations, at high altitudes fired from high speeds, if the bandit is high, too - up to 20nm. But those long range kills with the sparrow are exceptions. You really need to get up close and personal with it.

Here you can see, how I go about pushing in close, using snaking and shake-and-bake tactics. This is of course best applied in semi active engagements only.

Hey IronMike, thank you very much for your reply.

Unfortunately the issue I'm seeing is not so much that the AIM-7 is running out of energy, as it would still make the intercept in excess of mach 1 with the shot parameters I was using.

Rather it will radar lock onto chaff and guide to a collision course with that, rather than the airplane.

I was under the impression that such a thing should not be possible in a P-STT look-up scenario, so long as the lock remains unbroken.

I've attached the tacview recording of my last flight, both first two missiles are fired with the target at 2-3000 feet above my jet, against clear sky. However, halfway through intercept the AIM-7 locks onto an old bundle of chaff (5-6 seconds after it was dumped). The second missile I fire never even tracks and goes for the same bundle of chaff immediately off the rails.

As you can see in the recording, it's not that the missiles run out of energy or don't track, it's that they specifically start tracking chaff, particularly in a look-up for the first two shots (the last one I can discount because it's look-down).

Tacview-20190721-130453-DCS.zip.acmi.zip

I was under the impression that such a thing should not be possible in a P-STT look-up scenario, so long as the lock remains unbroken.

P-STT is not some unspoofable "super mode". Basically, P-STT drops doppler processing compared to PD-STT, thereby removing the doppler mode's blind spot around zero relative ground velocity (thus making notching by flying zero relative ground speed impossible). The radar can and will still be spoofed by chaff, which appear as false radar returns to both the radar and the missile. This means that while your radar may maintain track of the target, the missile can still go for the chaff. In fact, P-STT should be more prone to chaff spoofing than PD-STT, as neither the missile nor the radar have the ability to discriminate between chaff and actual target based on doppler shift.

In a lookup situation, there really is no need to use P-STT. Instead, use PD-STT and turn of MLC rejection (if you have a human RIO, Jester can't do that yet AFAIK).

Ok, I see what you mean. So, first of all, how it should work in real life - chaff could potentially break lock, it should also appear on radar like ecm strobes, etc... means it would prolly spook the radar instead of the missile, or maybe it would affect the missile's semi active seeker, too? What sLYFA says above is true, but I doubt we will ever know exactly, since these things are highly classified. It makes sense that in game a workaround is to spoof the missile directly, but what is visible in the tacview is excessive for sure. I also have never experienced it to be that bad on my end. The vid above btw is the exact same mission. However I really use aim7s for close quarters only most of the time and apart from the occasional miss, or dud off the rails, they do hit.

There is a missile guidance thread in the general bug section, where this report would probably fit best - guidance is completely out of our hands and the aim7 in general is done by ED. A new report would probably not hurt either.

However if this is always the case for you, something else might be wrong in the background, etc.. - although I would not have an idea what. But I never experienced this to be the norm. Also not recently.

Sorry that I am not more of a help here. But in any case, we will keep an eye out for it, too.

Is there a chance we'll get the -7MH at any point?

Is there a chance we'll get the -7MH at any point?

Code-wise it's not too difficult, thing is we have no info on the missile every being used by the F-14, was it after the F-14s service life? Did it require features not present in the F-14A/B?

There's just not enough information for us to act on unfortunately.

Well this is my view; the AIM-7M (emphasis on the M as its the only AIM7 the F14 carries as of now) shouldn't be able to guide on a CW signal, it is just quite simply incapable of doing so (the CW transmitter is guided by the pulse lock) as it guides on PD only. The last missile to guide on a CW signal was the F model which had dual PD and CW guidance. This though gives it an advantage over older CW AIM-7's as PD will filter out chaff. It will do so as the chaff will almost instantaneously drop to near 0 m/s after being deployed (like under a second kind of timings as far as i'm aware). This low V would then fall into the velocity gate and be filtered out meaning the missile wouldn't be decoyed by the chaff nor the main radar. There is only a small moment where the chaff would have an impact but this impact would be only to make the target look bigger as it would be only right behind the jet that this effect would register. The effect this should have is it would just increase the miss distance of the missile not decoy it completely. Now as to how much bigger the chaff would make the target look I don't know. But, as of now in DCS all PD missiles will eat chaff that is already completely lost its velocity. This is particularly bad for the amraam which can relock a target it looses but once it eats chaff it seems to just track on it instead of going back into its high PRF search mode from its medium PRF tracking mode.

With P-STT yes it should be much much much more vulnerable to chaff simply due to the fact that it has not velocity gate. It could even cause the radar to loose lock if you dump enough chaff quickly enough out of the back for the radar to track it instead of the main target. Now I don't doubt there are ways to counter this but considering the antiquated nature of the 14's electronics I have doubts if it has any mechanisms to counter chaff dumps in P-STT.

Now I noticed that in the missile code for the 14 you guys just have a clone of the AIM-7... does this AIM-7 use the new missile guidance and drag code from missiles_table.lua? (scripts/database/weapons)

Concerning the M/H as far as i'm aware it was just a M with components from a P which entered service in 1998 so imo I don't see any issues adding it into the game.

In a lookup situation, there really is no need to use P-STT. Instead, use PD-STT and turn of MLC rejection (if you have a human RIO, Jester can't do that yet AFAIK).

I always thought, that P-STT was useful for lookup situations only, as it will not get distracted by ground clutter then and has the advantage of having no blind spots compared to PD-STT (same speed filter). :huh:

So when would I use P-STT then?

The last missile to guide on a CW signal was the F model which had dual PD and CW guidance.

Speaking of the F model, why don't we have the AIM-7F for our DCS Tomcat?

Code-wise it's not too difficult, thing is we have no info on the missile every being used by the F-14, was it after the F-14s service life? Did it require features not present in the F-14A/B?

There isn't alot of info about the differences between the F1 and H builds on the internet. The IOC that seems to get tossed around is 1987, but I can't find any primary documents that directly reference that. I have seen multiple documents written in the 1997/8 time frame that reference the H-build as if it is in service, with one specifically referencing the adoption of the newer AIM-7P.

Every source I've seen references the H Build as a software upgrade for the AIM-7M. 90's Navy documentation I've read acknowledges the H Build exists, but does not explicitly state what it is or any differences in requirements exist. If anything the Navy generally lumps the AIM-7M and P together in literature.

A maintenance training document for the newer AIM-7P dated May 1998 references the F-14 and the LAU-92 as launch platforms for the AIM-7M/P, references training documents for the F-14A/B separately from the F-14D with reference to changes made for the adoption of the AIM-7P, and notes that the AIM-7P induces no changes to "immediate or operational level maintenance functions".

This is all highly subjective readings based off tertiary sources. Is this something your SMEs or ED could shed more light on? It'd be nice to have the option of slightly better CM rejection for later time period missions.

Thanks for the input guys,

I get that P-STT is by no means unspoofable, however as I understand SARH homing works by illuminating the target with a flood of radar waves, with the seeker just homing onto reflection.

Chaff will disrupt this reflection and therefore spoof a missile temporarily, but if the radar keeps tracking the original target, the missile should reacquire as soon as the chaff disperses or is no longer illuminated by the radar. This will in most cases cause the missile to be kinematically defeated (resulting intercept trajectory will cause the missile to pull significant extra G's)

In DCS however I see chaff working like flares in a very egregious and jarring way. They spoof the missile directly, even for old bundles that have hundreds of feet of separation and are no longer being illuminated (so there's nothing for the SARH missile to home in on). Missiles that were chaffed also have no chance of ever reacquiring the original contact, even if the radar track is never lost. The chance that this happens seems extremely high in singleplayer, due to the AI's ability to instantaneously pull into a perfect notch (even in look-up somehow).

The worst example of this is losing the missile to chaff spam on hot aspect engagements.

Pulse mode would have a very high chance of getting its track broken by chaff, but that's not what's happening in the sim as the radar keeps tracking.

I'd understand if this is something Heatblur has little influence over since missile guidance all happens on the side of ED, so I might as well throw a bug report on the pile in the hope something changes in the future.