reported earlier jdam still inaccurate beyond the 5m CEP

[Sinclair_76]

With the latest update marking targets with the TGP has become too inaccurate for JDAM use it seems. The usual 5m CEP has almost doubled in size it seems making it unusable against even the softest of targets. Does anyone have a workaround or system in place to deal with this issue?

Edited January 1, 2023 by Sinclair_76

[Sinclair_76]

GBU-38 5m CEP

https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104572/joint-direct-attack-munition-gbu-313238/

https://www.airandspaceforces.com/weapons-platforms/gbu-31-32-38-jdam/

 

Edited January 2, 2023 by Sinclair_76

[Sinclair_76]

I made a simple test miz to demonstrate.

Did 4 setups with 4x BTR-80's attacked by 4x GBU-38. First 2 setups are with TMS up to designate only. And the last 2 setups are with generating markpoints and then attacking the indivivual BTR's. 

It's a small dataset but in the first 2 setups, pretty much all -38's fall short.  The last 2 setups are pretty much spot on. GBU-38 parameters are default.

The grids are the coordinates of the BTR's I pulled from the ME map to corroborate the coordinates generated by the TGP. 

test-GBU38.miz Test-TOO-GBU-38-1.trk Test-TOO-GBU-38-2.trk Test-TOO-MARK-GBU-38-1.trk Test-TOO-MARK-GBU-38-2.trk

Edited January 2, 2023 by Sinclair_76

[Fromthedeep]

Is the tag 'PM evidence' placed there by a CM? This behaviour is intended?

[Hobel]

vor 8 Stunden schrieb Sinclair_76:

I made a simple test miz to demonstrate.

Did 4 setups with 4x BTR-80's attacked by 4x GBU-38. First 2 setups are with TMS up to designate only. And the last 2 setups are with generating markpoints and then attacking the indivivual BTR's. 

It's a small dataset but in the first 2 setups, pretty much all -38's fall short.  The last 2 setups are pretty much spot on. GBU-38 parameters are default.

test-GBU38.miz 7.98 kB · 2 Downloads Test-TOO-GBU-38-1.trk 996.95 kB · 2 Downloads Test-TOO-GBU-38-2.trk 1.08 MB · 2 Downloads Test-TOO-MARK-GBU-38-1.trk 1.63 MB · 2 Downloads Test-TOO-MARK-GBU-38-2.trk 2.24 MB · 2 Downloads

 

none of these files are shown to me in DCS.
can anyone here confirm this?

[Sinclair_76]

2 hours ago, Fromthedeep said:

Is the tag 'PM evidence' placed there by a CM? This behaviour is intended?

I think the CM placed the tag although it does not make sense to me since I am not second guessing the JDAM.

[TheBigTatanka]

Did you get a laser range with the TGP before designating?

Sent from my Pixel 4a (5G) using Tapatalk

[Sinclair_76]

1 hour ago, TheBigTatanka said:

Did you get a laser range with the TGP before designating?

Sent from my Pixel 4a (5G) using Tapatalk
 

Yes

[Sinclair_76]

17 hours ago, Hobel said:

none of these files are shown to me in DCS.
can anyone here confirm this?

What do you mean?

Aren't you able to download the files?

 

[Hobel]

vor 4 Minuten schrieb Sinclair_76:

What do you mean?

Aren't you able to download the files?

 

I can download them and also add them to my track folder. 

But then in dcs nothing is shown to me. 

[TobiasA]

Am 1.1.2023 um 13:07 schrieb Sinclair_76:

With the latest update marking targets with the TGP has become too inaccurate for JDAM use it seems. The usual 5m CEP has almost doubled in size it seems making it unusable against even the softest of targets. Does anyone have a workaround or system in place to deal with this issue?

 

I have the same issue- when a JDAM is used from 8nm slant range, the resolution of the system is so bad that it makes JDAMs unsuitable for anything harder than a truck.

Even with lasing.

The effect is coming from the system, the error is decreasing with slant range getting smaller.

Yes, I am laser ranging, yes, i pointed at the bottom of the vehicle, but they still fall long or short most of the time.

When dropping them from lower altitude or later in the DLZ they become more precise.

It probably is the way it is.

Edited January 3, 2023 by TobiasA

[Sinclair_76]

3 minutes ago, TobiasA said:

I have the same issue- when a JDAM is used from 8nm slant range, the resolution of the system is so bad that it makes JDAMs unsuitable for anything harder than a truck.

Even with lasing.

The effect is coming from the system, the error is decreasing with slant range getting smaller.

Yes, I am laser ranging, yes, i pointed at the bottom of the vehicle, but they still fall long or short most of the time.

When dropping them from lower altitude or later in the DLZ they become more precise.

It probably is the way it is.

 

It wasn't always like that. I wouldn't use them on MBT's since the 5m CEP in combination with the DCS damage model don't guarantee a hard kill. Usually fly XCAS/XAI with 2x -38 and 2x 12. Would reserve the LGB's for hard targets and the JDAM for softskins. But the TGP seems so out of wack it can't generate coordinates good enough for even softskins.  It is as if the TGP constantly ranges short by a couple of meters. For some odd reason that error disappears if I mark and use that. Even if the mark, after CZ, displays off target. 

49 minutes ago, Hobel said:

I can download them and also add them to my track folder. 

But then in dcs nothing is shown to me. 

I can download them and view the just fine. I am using latest beta not sure if that can be an issue.

[AstonMartinDBS]

18 hours ago, Hobel said:

none of these files are shown to me in DCS.
can anyone here confirm this?

I downloaded the first track (Test-TOO-GBU-38-1.trk) and was able to watch it (latest DCS OB installed).

The mission is placed in Nevada. If you don't have this map you cannot see those missions or tracks.

[AstonMartinDBS]

I was able to hit all four BTRs. One was a direct hit and three were very close.

NV F-16C GBU accuracy.trk

[Hobel]

vor 2 Stunden schrieb AstonMartinDBS:

I downloaded the first track (Test-TOO-GBU-38-1.trk) and was able to watch it (latest DCS OB installed).

The mission is placed in Nevada. If you don't have this map you cannot see those missions or tracks.

Ah yes that's it, I have not installed the map.  

General tip, please do all tests on Caucasus as far as possible.

[DukeAngus]

i find that a impact angle of 90 degrees with  a ground fuse  causes the most damage.

i have also found that releasing JDAMS a couple miles after max range helps the bomb land with more kinematic energy since it doesnt have to fly horizontally as far.

what i did would be after releasing the bomb i paused the plane and watched the bomb, that will tell you a lot about what the bomb is doing.

[Sinclair_76]

I've done all the above and all -38's keep falling several meters short, never had a bomb go long.

 

The one thing I haven't tried is gnd fuze. Could increase damage but will do nothing for falling short. Will try another theater as well as there were some problems with grid generation in NTTR in previous versions iirc.

 

Edited January 6, 2023 by Sinclair_76

[Sinclair_76]

I think the issues I am seeing might be related to 

 

Tried Caucasus and still have the same problems of -38's falling short.

 

[TobiasA]

Am 3.1.2023 um 18:08 schrieb DukeAngus:

i have also found that releasing JDAMS a couple miles after max range helps the bomb land with more kinematic energy since it doesnt have to fly horizontally as far.

The precision is higher because the TGP error is smaller.

JDAMs seem to fall shorter when you pickle from a larger distance. 

Edited January 6, 2023 by TobiasA

[Hobel]

vor 26 Minuten schrieb TobiasA:

JDAMs seem to fall shorter when you pickle from a larger distance. 

That's not the point

[Sinclair_76]

In the lower part of the WEZ. Direction of flight was from left to right. Still short. High precision, low accuracy.

null-also a bug

Edited January 6, 2023 by Sinclair_76

[TobiasA]

vor 2 Stunden schrieb Hobel:

That's not the point

It probably is 

[Sinclair_76]

45 minutes ago, TobiasA said:

It probably is 

Long distance, short distance. All my drops were within the WEZ. Even at short distance (low in the WEZ bracket) the -38's fall well short. So I don't think distance plays an important factor in the error. 

[TobiasA]

vor 2 Stunden schrieb Sinclair_76:

Long distance, short distance. All my drops were within the WEZ. Even at short distance (low in the WEZ bracket) the -38's fall well short. So I don't think distance plays an important factor in the error. 

Did you lase prior to each drop?

[Hobel]

vor 44 Minuten schrieb TobiasA:

Did you lase prior to each drop?

  

Am 2.1.2023 um 23:47 schrieb Sinclair_76:

Yes

 

 

Why don't you test it yourself and then share the results?

Edited January 6, 2023 by Hobel