GM Radar and GBU-31 Help?

[swartbyron]

GM Radar and GBU-31 Help?

I've been leaning the air to ground radar and I'm having trouble with the GBU-31 landing way off target in most cases.

When using a steerpoint or the TGP to create a SPI for the GBU I get a direct hit every time but it seems like I'm getting or creating an error when using the ground radar to designate the target.

Anybody else having trouble or any advice?

 

Clear picture showing a good return of and Il-76 parked on the ramp:

Freeze and TMS up to create a SPI:

GBU-31 within parameters:

Bomb landing a long way off. I'm not expecting a pin point strike from a ground radar return but its not even landing on the ramp: 

Edited December 23, 2021 by swartbyron

[razo+r]

Maybe related with this bug

https://forums.eagle.ru/topic/285593-a-g-radar-frozen-slews-move-spi-twice-as-far-as-the-slew/

[swartbyron]

2 hours ago, razo+r said:

Maybe related with this bug

https://forums.eagle.ru/topic/285593-a-g-radar-frozen-slews-move-spi-twice-as-far-as-the-slew/

Thanks for the link, yes its possibly the same thing?

Lets hope its a bug and on the repair list. 

[Frederf]

"TMS up to create a SPI" This is wrong thinking. SPI was at radar cursors the same as before or after designation. Since there is no actual FTT implemented yet it's of no use to designate the GM/SEA radar modes. Just slew the cursors over the target and use that. Don't TMS forward in most cases. It's unnecessary in most situation and can only cause problems.

[swartbyron]

2 hours ago, Frederf said:

"TMS up to create a SPI" This is wrong thinking. SPI was at radar cursors the same as before or after designation. Since there is no actual FTT implemented yet it's of no use to designate the GM/SEA radar modes. Just slew the cursors over the target and use that. Don't TMS forward in most cases. It's unnecessary in most situation and can only cause problems.

Wow this worked a treat!

Thanks 

 

Seems its not necessary to freeze the picture in most cases if you get it lined up in one sweep.
What would the TMS forward function do in this radar mode in the real jet and the sim when its working?

Edited December 23, 2021 by swartbyron

[Frederf]

In the APG-68 that I know of there is only search and B-scan FTT. In newer APG-66 (and maybe -68v5 I don't know) they inserted a sort of middle PPI FTT that memorizes the search imagery but keeps it in PPI. Mind you the radar is still radiating but only around the tracked discrete so imagery around it is just a saved snapshot from when track was started. From PPI FTT you can TMS forward again and go to the B-scan FTT which is blank screen, B scope, and the radar track the discrete return. TMS aft from either scan mode would return to search.

Be aware that either FTT is looking for a discrete return (aka a bright dot) and will fail if designation happens away from a trackable object. FTT diamond means a solid track on a thing like a building. I think devs got confused that PPI FTT "freezes the display" means the radar enters freeze mode which is something quite different. The value in FTT is that it's constantly checking the edges of the discrete and refining the track kinda like a Maverick in centroid tracking a tank optically. Cursors-in-search kinda just puts the cursors over the rasterized picture. From what I've heard real F-16 pilots overwhelmingly prefer to put the cursor over the target in search and not enter FTT in most situations.

What I don't know is what happens when your "FTT" target moves. The F stands for fixed but moving stuff (e.g. a ship) can show up in GM/SEA just as well as buildings. You FTT a parked tank and then it starts moving; what happens? Right now in DCS it'll show that tracking diamond but the object that track represents can drive out from under the diamond which isn't right. Either the track follows the mover or the diamond changes to a square (coast) and/or breaks track back to search.