Enemy aircraft give IFF mode 4 positive reply after latest update

[Viper 13]

DCS 2.9.2.49629 Open Beta MT

Hi 

After the latest patch enemy aircraft now give IFF mode 4 positive reply.

I created a simple mission to demonstrate the problem.

From an air-start a Mig-21 is ahead of my F-15E, I lock it in STT and then IFF the contact.
The Mig-21 gives a positive reply to the Mode 4 IFF
 

IFF Mode 4.trk

Edited December 20, 2023 by Viper 13
typo error

[Galinette]

Thanks for the track, we could reproduce the issue.

It only impacts STT and Mode 4 used together.

Until next patch where it will be fixed, there is a simple way to avoid it. Just do a Mode 4 interrogation (AAI or EID) in a scanning mode (TWS, RWS) once.

The issue should disappear until the end of the session.

[zlm63682]

20 hours ago, Kercheiz said:

Thanks for the track, we could reproduce the issue.

It only impacts STT and Mode 4 used together.

Until next patch where it will be fixed, there is a simple way to avoid it. Just do a Mode 4 interrogation (AAI or EID) in a scanning mode (TWS, RWS) once.

The issue should disappear until the end of the session.

Hi

i found another issue

if i put an enemy mig29 and a friendly f15 both heading towards me and use the auto NCTR function

i am able to auto NCTR both aircrafts under TWS lock and tell it's friendly or foe

but if i unlock the target, then the 2 radar signals will confuse and they both show a friendly F15 even if one is an enemy mig29

[Galinette]

23 hours ago, zlm63682 said:

Hi

i found another issue

if i put an enemy mig29 and a friendly f15 both heading towards me and use the auto NCTR function

i am able to auto NCTR both aircrafts under TWS lock and tell it's friendly or foe

but if i unlock the target, then the 2 radar signals will confuse and they both show a friendly F15 even if one is an enemy mig29

What's the targets separation? Could you provide a short trk?

Edited December 22, 2023 by Kercheiz

[zlm63682]

4 hours ago, Kercheiz said:

What's the targets separation? Could you provide a short trk?

 

hi, sorry i dont know how to get a trk file

i put them very close, around 0.8 nm to each other, same altitude 36k, both heading towards me because i was testing the AUTO ID thing

only happens if i use the AUTO ACQUISITION AFT to unlock one of them in TWS and both radar signals give me a same IFF results ( both friendly F15)

works fine if i use the AUTO ACQUISITION PRESS DOWN to wipe the whole radar screen and the aircraft can tell the 2 different new signals

[Galinette]

Need to check what actually happens. But having two aircraft at the same distance, and with little angular separation, will cause wrong IFF correlations, and that's a feature.

IFF is only able to sort contacts by range, there is a very very poor angular resolution (several degrees)

To make a TRK, just quit the mission and save track from the debriefing window. In order for it to be useable for development, the shorter the better, so best is air spawning in the desired situation and do the radar/iff test immediately.

It's also possible that TWS chose to make a subtrack as both contacts where basically formation flying.

Edited December 22, 2023 by Kercheiz

[zlm63682]

1 hour ago, Kercheiz said:

Need to check what actually happens. But having two aircraft at the same distance, and with little angular separation, will cause wrong IFF correlations, and that's a feature.

IFF is only able to sort contacts by range, there is a very very poor angular resolution (several degrees)

To make a TRK, just quit the mission and save track from the debriefing window. In order for it to be useable for development, the shorter the better, so best is air spawning in the desired situation and do the radar/iff test immediately.

It's also possible that TWS chose to make a subtrack as both contacts where basically formation flying.

 

hi

i think i have somewhat reproduced my problem and attached is my trk file

i dont know if it's the modeled feature or just a bug, just very confusing.

seems only having this problem in AUTO ID , Manual ID works fine   under the same circumstance.

 

 

 

 

F15 IFF2..trk

Edited December 22, 2023 by zlm63682