investigating Bug: HOJ broken when target is detected by IRST

[BlackPixxel]

There is a bug in the HOJ logic:

Under some conditions, the HOJ lock will turn into an IRST lock, which makes it impossible to launch R-27 in HOJ and also means that the target tracking will break when the target exceeds the gimbal limits of the IRST.

Following steps to reproduce, target needs to have high IR signature (e.g. Su-27, F-15C)

1. Non-jamming target is locked at long range.

2. Target turns on ECM, lock transitions to HOJ

3. Target turns on Afterburner before burnthrough range

4. If target is within parameters for IRST detection, the lock will switch from radar HOJ into an IR lock. Radar cannot be enforced by turning IRST off. It will just turn to memory mode and switch back to IRST. Exceeding the gimbal limits from IRST causes loss of lock. Even tough at less than 15° elevation the target would still be within the gimbal limits of the radar. Launching an R-27ER in HOJ is impossible, because for that the radar HOJ mode would be required, but the lock is stuck in IRST. Still the jamstrobe will be shown on the HDD.

Only within burnthrough range can the lock turned back into a radar lock from this unwanted IRST lock.

 

What should happen instead at step 4: Lock should simply stay radar HOJ unless manually transfered to IRST by the pilot.

The following trackfile showcases the issue. Lock turns into IRST lock when HOJ target gets within IRST parameters, I cannot enforce a radar HOJ lock and when I exceed vertical EO gimbal limit by putting the target below my nose I lose lock.

bug_test-20230105-212204_ecm_bug.trk

Edited January 5, 2023 by BlackPixxel

[[ED]Ben]

Hi - Would you be able to create a new track showing this? Thew attached one does not play back for me. Thanks

[BlackPixxel]

On 1/30/2023 at 12:07 PM, [ED]Obi said:

Hi - Would you be able to create a new track showing this? Thew attached one does not play back for me. Thanks

Hi, here is another example from singleplayer. I hope it works: HOJ_bug2.trk

I lock the bomber with radar. He starts jamming. Instead of keeping a radar HOJ lock, it turns into an EO lock. When I am in kinematic range for the R-27ER, Launch Authorisation blinks but never becomes solid. Holding down the trigger does nothing, the missile cannot be launched.

Forcing EO off does not switch the lock to a radar lock, it will just stay in extrapolation mode for 4 seconds and EO will switch back on.

Extending elevation gimbal limits of IRST causes loss of lock, even though the target is still within radar gimbals.

Only by locking the target outside of the IRST gimbal limit I get a proper radar HOJ lock and can fire the missile.

 

Hope it helps!

[Ironhand]

Just to add a bit more information. I took control of your flight several times and was able to launch once the range closed to 21-22 km.

EDIT: Would that be the burn through range for a bomber in DCS? I’ve forgotten and didn’t think to check.

EDIT 2: Just made a quick check. That's the burn through range.

Edited February 1, 2023 by Ironhand

[okopanja]

On 1/5/2023 at 9:59 PM, BlackPixxel said:

Still the jamstrobe will be shown on the HDD.

Is the presence of jamming strobe in EO only, a bit strange? Is it work creating a separate bug report (EO only locked, radar off, HUD displays range, HDD still shows strobe with no target overlayed?)

[BlackPixxel]

Bug is still present.

[NuII]

On 1/5/2023 at 9:59 PM, BlackPixxel said:

There is a bug in the HOJ logic:

Under some conditions, the HOJ lock will turn into an IRST lock, which makes it impossible to launch R-27 in HOJ and also means that the target tracking will break when the target exceeds the gimbal limits of the IRST.

Following steps to reproduce, target needs to have high IR signature (e.g. Su-27, F-15C)

1. Non-jamming target is locked at long range.

2. Target turns on ECM, lock transitions to HOJ

3. Target turns on Afterburner before burnthrough range

4. If target is within parameters for IRST detection, the lock will switch from radar HOJ into an IR lock. Radar cannot be enforced by turning IRST off. It will just turn to memory mode and switch back to IRST. Exceeding the gimbal limits from IRST causes loss of lock. Even tough at less than 15° elevation the target would still be within the gimbal limits of the radar. Launching an R-27ER in HOJ is impossible, because for that the radar HOJ mode would be required, but the lock is stuck in IRST. Still the jamstrobe will be shown on the HDD.

Only within burnthrough range can the lock turned back into a radar lock from this unwanted IRST lock.

 

What should happen instead at step 4: Lock should simply stay radar HOJ unless manually transfered to IRST by the pilot.

The following trackfile showcases the issue. Lock turns into IRST lock when HOJ target gets within IRST parameters, I cannot enforce a radar HOJ lock and when I exceed vertical EO gimbal limit by putting the target below my nose I lose lock.

bug_test-20230105-212204_ecm_bug.trk 303.47 kB · 19 downloads

 

You have to manualy switch to HOJ (depress the jamming signal, not the dot). The point of ECM activation of your target is to lose lock before burnthrough 45km, for FC3 avionics I am talking. So naturally it tries to reacquired with EO. It would be to easy to automatically switch to HOJ.

[BlackPixxel]

Bug is still present and very annoying. Makes it impossible to fire R-27ER at jamming targets when they are within IRST range.

[BlackPixxel]

Here is another example of the bug. I lock the F-15E, he turns on ECM and keeps it on, my lock switches to IRST. I maneuver him out of my vertical IRST gimbal limit, but keep him within radar gimbal limit. Lock is lost, even though radar still points at him and should go HOJ.

HOJ_IRST_BUG.trk

[okopanja]

1 hour ago, BlackPixxel said:

Here is another example of the bug. I lock the F-15E, he turns on ECM and keeps it on, my lock switches to IRST. I maneuver him out of my vertical IRST gimbal limit, but keep him within radar gimbal limit. Lock is lost, even though radar still points at him and should go HOJ.

HOJ_IRST_BUG.trk 100.9 kB · 0 downloads

@BlackPixxelI am not at home to try, but I think F-15E does not have a jammer implemented yet. I will ask someone who has it to confirm.

[BlackPixxel]

It's jammer was working

[okopanja]

12 minutes ago, BlackPixxel said:

It's jammer was working

I might be mistaken, I still wait for the feedback from someone...

[draconus]

55 minutes ago, okopanja said:

I might be mistaken, I still wait for the feedback from someone...

Maybe it was AI?

[okopanja]

4 hours ago, draconus said:

Maybe it was AI?

In this case it's an AI. Just to let you know: AI or not AI, the ECM effect is simulated on shooter's side. Your cockpit switch for ECM is just one remote control switch that triggers the effect to be on/off for target X in all other clients.

On top of it, this is F-15E provided by Razbam, so technically there should be no difference between it and the cockpit connected F-15E.

Edited May 17, 2024 by okopanja
extended...

[draconus]

On 5/17/2024 at 7:18 PM, okopanja said:

In this case it's an AI. Just to let you know: AI or not AI, the ECM effect is simulated on shooter's side. Your cockpit switch for ECM is just one remote control switch that triggers the effect to be on/off for target X in all other clients.

On top of it, this is F-15E provided by Razbam, so technically there should be no difference between it and the cockpit connected F-15E.

I don't understand your conclusions. Both F-15E and F-15E Suite 4+ AI can and will use ECM, they may only have default setting different.

[okopanja]

8 minutes ago, draconus said:

I don't understand your conclusions. Both F-15E and F-15E Suite 4+ AI can and will use ECM, they may only have default setting different.

Just saying that ECM is already there in every DCS installation(has to be simulated on radar operator side), missing is the switch in cockpit.

[draconus]

On 5/19/2024 at 12:01 PM, okopanja said:

Just saying that ECM is already there in every DCS installation(has to be simulated on radar operator side), missing is the switch in cockpit.

And what's your point?

BlackPixxel said the F-15E was jamming. You replied that F-15E has no ECM as of yet. I said that maybe it was AI, which do have ECM available and you still talk about some cockpit implementations.

Nevermind, explained in PMs.

Edited May 21, 2024 by draconus

[Irisz]

It won't play the track file for me! MiG-29S flies instead. He also uses ECM interference, the radar lock above 50 km is rejected because of the interference!
It doesn't matter at what radar repetition frequency I follow the target. The default N001 radar repetition frequency operating principle is that in ILV mode, the IRST is automatically activated if the radar loses lock and the IRST has enough power to track the target. In Hi and MED radar repetition frequency mode, this does not work if the radar loses the target, IRST must be turned on manually. (this is the problem with Flaming Cliffs Flanker and Fulcrum)

This should be fixed by ED and should be automatic in all radar repetition frequencies of the FC3 Flanker and Fulcrum types.

We do not have the radar repetition frequency displayed on the Flanker HUD display under radar lock, we cannot track what repetition frequency the radar uses. In reality, the Flanker works like this, the pilot can see on the HUD display at what frequency the radar repeats during target tracking.

In Fulcrum, this is done with a switch, but the HUD display does not show it.

Flaming Cliffs is incomplete and fantasy based in several areas, I think this is a good suggestion.

There is, however, an even better option, although it requires development! real ECM interference should appear on the HUD display, not fantasy-based as in DCS World, as it can be seen here in the picture on the Flanker HUD display!

We also deserve care, not only NATO pilots, who are loved in every patch!

Edited May 21, 2024 by Irisz

[draconus]

29 minutes ago, Irisz said:

Flaming Cliffs is incomplete and fantasy based in several areas, I think this is a good suggestion.

Yes, it's a good suggestion, probably not the first one at that, but it's not a reason to hijack this thread/bug report. Mind that FC3 has simplified avionics model. We all want it realistic but it will never be fully simulated in this product. Your "fantasy" remark is uncalled for. You're new here so you should also read more about the reasons why NATO is so vastly represented in full fidelity compared to Redfor. We have full fidelity MiG-29A coming soon - let's see what it brings.

[Irisz]

32 minutes ago, draconus said:

Yes, it's a good suggestion, probably not the first one at that, but it's not a reason to hijack this thread/bug report. Mind that FC3 has simplified avionics model. We all want it realistic but it will never be fully simulated in this product. Your "fantasy" remark is uncalled for. You're new here so you should also read more about the reasons why NATO is so vastly represented in full fidelity compared to Redfor. We have full fidelity MiG-29A coming soon - let's see what it brings.

There is no development without criticism!

[Ironhand]

On 5/17/2024 at 5:21 AM, BlackPixxel said:

Here is another example of the bug. I lock the F-15E, he turns on ECM and keeps it on, my lock switches to IRST. I maneuver him out of my vertical IRST gimbal limit, but keep him within radar gimbal limit. Lock is lost, even though radar still points at him and should go HOJ.

HOJ_IRST_BUG.trk 100.9 kB · 7 downloads

Finally had an opportunity to look at this. The lock isn't lost, I don't think. It's still there. It's even indicated on the HUD. What isn't indicated is the EORL that I think you're expecting. When that is there, you'll have range information. Without it, you don't. And that might actually be the issue. I took your TRK file and edited it to add 2 R-27ERs. Took control of your track after the EOS locked your target, engaged launch authorization override, and was able to launch the R-27ER prior to EORL showing up. That wouldn't be possible without a radar lock. TRK attached.

BlackPixxel_HOJ_IRST_BUG-Reflown.trk

[BlackPixxel]

There is no radar lock in my example, as soon as I leave the vertical IRST gimbal limits the radar goes back to scanning mode.

It should not be necessary to use LA override. And with LA override you can launch on notching bandits from an IRST lock lock. This does not mean that there is a radar lock.

Edited May 28, 2024 by BlackPixxel

[Ironhand]

23 hours ago, BlackPixxel said:

There is no radar lock in my example, as soon as I leave the vertical IRST gimbal limits the radar goes back to scanning mode.

It should not be necessary to use LA override. And with LA override you can launch on notching bandits from an IRST lock lock. This does not mean that there is a radar lock.

 

Watched your track again and, this time, it played back differently. And I see what you mean.

Quote

…And with LA override you can launch on notching bandits from an IRST lock lock…

And that would be another bug, if that is, indeed, the case.

[BlackPixxel]

6 hours ago, Ironhand said:

And that would be another bug, if that is, indeed, the case.

I mean that it will allow you to launch the missile, and that it does not mean that there is a radar lock by using override and having the missile leave the rail.

The missile will of course not track in that case, as the lock remains EO when the target notches.