fixed Bug: LA incorrectly given for IR missiles

[BlackPixxel]

There is the following bug in Su-27, Su-33 and MiG-29 that makes it likely for IR missiles to not track the target after launch:

When the target is directly along the boresight of the aircraft, LA (Launch authorisation) is correctly given when the missile seeker is within range to acquire the target and when the target is within kinematic range of the missile.

But the further the target is off-boresight, the earlier the aircraft will give LA before the missile seeker is actually able to pick up the heat signature.

This is very problematic, as it gives the player the impression that the missile is locked and allows him to shoot the missile in longer range off-boresight scenarios. But in the end, the missile will just fly straight and not track the target if the range at which LA was given is beyond the seeker range of the missile.

 

The attached trackfile showcases the issue. The off boresight target is acquired, and the ET is launched as soon as LA is given. But due to the bug LA is given before the missile seeker actually sees the target. So the missile just leaves the rail and flies straight and unguided.

ET_off_boresight.trk

Meanwhile, in the head on example LA is given at the range where the seeker actually sees the target and it correctly tracks.

ET_head_on.trk

 

Hope it can be solved, as it frequently causes missile to miss.

Thank you!

Edited January 3, 2023 by BlackPixxel

[Ironhand]

I took control of your off boresight TRK and, after the initial launch authorization, made a quick turn into the target. Lost launch authorization until roughly the same range as the boresight TRK. Good catch.

[TheFreshPrince]

This is likely the reason for what I experienced here:

 

But I got no reply, so don't count on any reaction by ED. FC3 is pretty much dead officially from what I witnessed here on the forum. 

[draconus]

11 hours ago, TheFreshPrince said:

FC3 is pretty much dead officially

link?

[TheFreshPrince]

Point 5

[Ironhand]

2 hours ago, TheFreshPrince said:

Point 5

Ahhh. Point 5 has been in effect for years. While they will fix FC3 bugs, they will not add features to existing aircraft nor create new FC3 aircraft. So it’s not abandonware. Simply not developmentware.

[Exorcet]

15 hours ago, TheFreshPrince said:

FC3 is pretty much dead officially from what I witnessed here on the forum. 

From what I've seen on the forum, FC3 is still getting significant updates. Just look at the F-15's radar. The R-27 is also the missile getting the most attention from ED after the AIM-120, and the only planes to carry it are from FC3.

[TheFreshPrince]

There have been some missile changes in the past year but that's about it from what I can read from the official changelogs. Maybe they do some unofficial fixes, who knows. But except the missiles, there's nothing about FC3 in the changelogs or I've missed it.

Just to be clear, I don't think there is much that needs fix anyway. I love the FC3 package and it works beautifully well. Currently, in Air-to-Air-Combat the FC3 planes are way better than other modules (except the F-16 maybe). The R27ET and R73 are probably the best missiles in DCS at the moment.

I just want to point out that there might be no official reply or fix to the issue in this or in my thread, because ED clearly has other priorities.

Edited January 6, 2023 by TheFreshPrince

[draconus]

34 minutes ago, TheFreshPrince said:

I just want to point out that there might be no official reply or fix to the issue in this or in my thread, because ED clearly has other priorities.

You got answered by many users and didn't care to reply or thank.

There are still fixes done for FC3, not all are noted in the change log.

[TheFreshPrince]

False, I liked or thanked every post that was helpful. I also literally wrote thank you. But after a few posts there was not much new so I waited for an official reply, which never happened. There's also no reason to reply if someone explains something to me, I will just acknowledge it and press the like or thank button. And if it's not helpful, then I won't... Also no need to spam this thread with accusations. 

[Coxy_99]

Can we please not de rail the thread its a bug. @BIGNEWY can we get a clean up please.

[Pavlin_33]

On 4/13/2023 at 11:00 PM, BlackPixxel said:

Bug is still present.

Yes, but they managed to keep the 27R from reacquiring the target, so they are working on it

[Flappie]

Thanks for the heads up!

Issue reproduced and reported.

[Pavlin_33]

5 hours ago, Flappie said:

Thanks for the heads up!

Issue reproduced and reported.

 

Edited June 10, 2023 by Pavlin_33

[BlackPixxel]

I think I found the issue in the calculation.

Here is the same scenario, but I shifted the position of my aircraft in such a way that the heading of me is the same, but that the target is directly in front of me.

So the difference in heading angle between target and me is the same as in the previous test.

And what do we get? The same launch authorisation range of ~ 9 km.

HEATER_LA_offset.trk

 

IR signature is aspect dependant in DCS. So in the Su-27 code it needs to check the aspect angle of the target as one of the factors for a valid seeker lock.

But it seems that the DCS code simply calculates the angular difference of Su-27 and target vectors. It does NOT take into consideration, that the off-boresight angle also adds to that angular difference. A pretty bad mistake.

This incorrect calculation only happens for the aircraft, once the missile is launched it calculates the true target aspect correctly and as a result is unable to find it. It was launched to early.

 

Would be nice if this could be fixed in one of the next patches.

Edited August 13, 2023 by BlackPixxel

[BlackPixxel]

To further prove my point, here is another test.

But at first, take into consideration that in a head on scenario, the ET will get LA at about 7 km on that Su-25.

In this new test, the target is off boresight, but its heading is exactly the opposite of mine. So the heading difference is exactly the same 180° as in the case where I fly headon into the SU-25. What is different is only that the target is positioned off boresight, so we fly past each other. It means that I will view the target not from the front, but from a flanking aspect. This should increase my ET seeker range.

But it doesn't. I get exactly the same ~7 km LA range. This is because DCS only substracts the directions of me and the target to get the aspect angle, instead of taking the effect of the off-boresight angle into consideration.

HEATER_LA_BUG_4.trk

[Ironhand]

Hopefully it’s an easy fix and won’t have a bottom dwelling priority.

[Teknetinium]

Good find as always Pixxel! Ironhand, I hope MIG-29A is in the works as well, Any news? 

 

Edited August 13, 2023 by Teknetinium

[BlackPixxel]

@BIGNEWY

Could this bug be forwarded again to a dev? It is now very clear what the issue is (see my recent posts). The effective target apect is calculated incorrectly for the seeker lock range estimation.

[BIGNEWY]

The issue is already reported, just need to be patient now. 

thanks

[Flappie]

@BlackPixxel  Your last comments were added to the report.

[Flappie]

This is now fixed internally.

Thanks you for your efforts, @BlackPixxel.

[BlackPixxel]

Awesome, good to hear!!

[BlackPixxel]

Fixed with todays update!!

[BIGNEWY]

thanks