fixed TGP not aligned to HUD marker?

[AngryViper.101]

Good evening

I am having a strange problem using the TGP to mark some targets.

Firstly, the block on the HUD is way above the actual targets, even though the targets are centered in the TGP video.

 

However, my bombs are falling 'over' the targets...

 

Edited January 3, 2022 by warford

[Frederf]

I notice your TGP has long whiskers indicating it's slaved to steerpoint. Either your  steerpoint is not at the surface level or the airplane is having an altitimetry error such that it is higher/lower than it thinks it is. What is the pressure and temperature of the mission? If you set TGP to area track and slew over targets is TD box on HUD over tanks?

[twistking]

21 hours ago, Frederf said:

I notice your TGP has long whiskers indicating it's slaved to steerpoint. Either your  steerpoint is not at the surface level or the airplane is having an altitimetry error such that it is higher/lower than it thinks it is. What is the pressure and temperature of the mission? If you set TGP to area track and slew over targets is TD box on HUD over tanks?

can you be more specific about the "whiskers"? i played around with the targeting pod, slewing an CZ, but i could not find any indication if it was slaved to steerpoint. for me the "slaved" tgp has the same symbols as tgp in inertia track mode (single tms aft).

Edited January 4, 2022 by twistking

[Frederf]

The crosshairs are short when self-tracking and long when slaved. At least I thought that's supposed to be the convention. I notice that TMS aft once from area track is long crosshairs but definitely not slaved. In any case, TGP is slaved to steerpoint if you press TMS aft a bunch or press CZ. When slaved to steer the crosshairs (whiskers) are long.

I ask because if the steerpoint is not at the surface then you'll deliver your bomb to a point in space in mid air. It will then fly through this midair point and l and somewhere unexpected on the far side. When TGP is area tracking I have a lot more confidence that the target location is on the surface. Notice there is no range indication like T6.6 in the lower left corner.

I see in your pictures the elevation reported by the TGP is 25' which should be surface. I also see green text. Is that a mod? As crazy as it sounds mods can do weird things even when it doesn't seem like it should be related at all.

Reasons for a miss can usually be categorized as: aimpoint wasn't at the target, airplane wasn't where airplane thought it was, or ballistics prediction from airplane to aimpoint is inaccurate to the actual bomb. Making sure the TGP reported position is equal to the target position should take care of the first one.

I'm suspicious of the second category noting that your radar altimeter is much higher than your barometric altimeter. Your airplane thinks its 1200' lower than the distance from you to dirt. I am gathering examples and notice that when temperature and pressure are non standard there are significant vertical errors in HUD symbol display. This suggests something strange with ownship assumed altitude. I would be interested in seeing the INS page SALT value and the info bar (Ctrl-Y) true altitude at the same time for comparison.

[Dannyvandelft]

Good evening
I am having a strange problem using the TGP to mark some targets.
Firstly, the block on the HUD is way above the actual targets, even though the targets are centered in the TGP video.
 
However, my bombs are falling 'over' the targets...


 

Looks to me like you're not locked onto anything. Point or Area track. So your bombs are just freefalling. Hit TMS up for a Point Track, or TMS right for an Area Track.

Sent from my SM-G960U using Tapatalk

[AngryViper.101]

Hi, I tried TMS up with same results. How do I align the radar and baro altitude? Is that the reason the tgp looks somewhere that is not in sync with the square block on the HUD? Thanks

Edited January 4, 2022 by warford

[Rongor]

38 minutes ago, warford said:

Hi, I tried TMS up with same results. How do I align the radar and baro altitude? Is that the reason the tgp looks somewhere that is not in sync with the square block on the HUD? Thanks

 

Set your altimeter to the QNH set in the mission. This is an everday procedure in real life aviation, if you aren't sure what this is about, you'll find plenty of stuff on this in the net.

Think of QNH as the current meteorological pressure at sea level, calculated for your area. Due to weather, the QNH does change and has to be fetched and set into your altimeter for every flight, even during flights (if they take long or you transit into different regions, because weather may change during an hour and of course might be different in a region 100 NM away). You will find the value in the mission briefing. If you created the mission by yourself and didn't change anything in the weather settings, the standard 29.92 will do it.

Take care to flip the little lever at the bottom right of your altimeter to ELEC and keep it there for some seconds until the indicators stop adjusting. At cold start, this lever may be on PNEU, which is kind of a backup solution only. Only then set the QNH value by turning the dial. Ideally do this before engaging INS alignment, or at least during the first two minutes of alignment, if you chose to go NORM alignment.

If you don't know where to find your current QNH while sitting on the parking spot, look up your current elevation on the F10 map, then turn the dial until the altimeter shows this elevation.

 

Radar alt and baro alt still will show differences, this is due to terrain of course. So in most cases your baro alt will be higher. On your pic it is the opposite, that is why it's obvious you didn't set it, as there shouldn't be any 1200 ft terrain depressions below sea level on any of the DCS maps.

Edited January 4, 2022 by Rongor

[Rongor]

6 hours ago, Dannyvandelft said:

Looks to me like you're not locked onto anything. Point or Area track. So your bombs are just freefalling. Hit TMS up for a Point Track, or TMS right for an Area Track.

This isn't really evidence. We see the situation after release, so it doesn't matter if his TGP is tracking the target.

As long as the SFW received the correct data at some time before pickle (which it apparently didn't somehow).

He would have to tell us if he sent the data from a tracking TGP to the CBU before dropping. If he didn't, why did CCRP release the bomb? Only if the CCRP took the steerpoint or the target was designated with a different method (HUD).

The misalignment of the TGP in the HUD is a hint, that even an evidently tracking TGP wouldn't have provided the correct data.

 

Edited January 4, 2022 by Rongor
I like editing stuff

[Deano87]

While changing the QNH set will correct the altimeter discrepancy I don't think it will solve the issue of the vertical steerpoint/spi offset in the HUD.

[AngryViper.101]

Hi

I have tried the procedure again using a laser guided bomb, which hits the target. but the HUD 'block' that indicates where the TGP is looking is still not aligned with the mark point?

 

the laser guided bomb hits the target successfully, but i want to understand why the slew 'box' on the HUD is way 'over' the target, even when the TGP video shows that it is point tracking the two targets lower down on the HUD?

 

[Rongor]

The laser will of course put its spot on the very location the TGP is showing in your MFD so what did you expect? It is to be expected that LGB will hit in this case. The laser doesn't care for the misalignment in your HUD and so won't the laser seeker in that LGB.

2 hours ago, warford said:

I have tried the procedure again

 

the laser guided bomb hits the target successfully, but i want to understand why the slew 'box' on the HUD is way 'over' the target, even when the TGP video shows that it is point tracking the two targets lower down on the HUD?

I think we have understood the problem but you didn't really respond to the hints that were given so far.

What exactly is 'the procedure' you now tried again? Explain it step by step or even better send a track.

What about the Altimeter setting and INS alignment?

Frederf asked if you are using some kind of mod. You didn't tell.

Also cutting down your screenshots isn't helpful as many possible clues are now outside of the frame.

 

 

[AngryViper.101]

Hi

Ok, thanks for the reply.

I will try and summarize this better in future.

Still learning and most likely missing a piece of the puzzle 

[QuiGon]

18 hours ago, Rongor said:

The laser will of course put its spot on the very location the TGP is showing in your MFD so what did you expect? It is to be expected that LGB will hit in this case. The laser doesn't care for the misalignment in your HUD and so won't the laser seeker in that LGB.

But the bomb can only guide on the laser if it sees it and that might not be the case if the calculated SPI is so far off, that the CCRP system leads you to drop the bomb to far off the target, so it can't guide on the laser.

Edited January 6, 2022 by QuiGon

[Deano87]

The reason your HUD box is vertically offset from the target is the mission pressure setting. It’s a long standing bug, changing the altimeter doesn’t work (at least it didn’t last time I tried). So you must set the mission pressure to standard and it will at least resolve your issue.

[AngryViper.101]

Deano87 , where do i set the 'mission pressure' thanks in advance

[Deano87]

I’m doing this on my phone so apologies for the quality of the pic. But in the mission editor you select the Time and Weather tab and you change the QNH to 29.92.

And here is the bug report I made on this issue.

As far as I know this hasn’t been fixed but tbh most of the servers I fly on use standard pressure.

 

 

[Rongor]

5 hours ago, QuiGon said:

But the bomb can only guide on the laser if it sees it and that might not be the case if the calculated SOI is so far off, that the CCRP system leads you to drop the bomb to far off the target, so it can't guide on the laser.

I agree, though in his two drops from 8000R and 14000B it still worked fine.

[AngryViper.101]

On 1/6/2022 at 12:15 AM, Deano87 said:

I’m doing this on my phone so apologies for the quality of the pic. But in the mission editor you select the Time and Weather tab and you change the QNH to 29.92.

And here is the bug report I made on this issue.

As far as I know this hasn’t been fixed but tbh most of the servers I fly on use standard pressure.

 

 

Hi, I tried setting qnh to 29.92 but it made no difference

[Frederf]

On the ground before first takeoff you can watch Kollsman knob directly change diamond vertical position. But takeoff with any setting and diamond magically corrects itself to true position and Kollsman has no effect. Landing again briefly I had two diamonds one at in-flight position and the other according to ground behavior in a vertical stack. Within a few seconds the system "fights" and the diamonds flicker about and it settles on the ground behavior. Seems that in-flight is completely ignoring anything the pilot does at least when it comes to diamond placement.

This was with ISA conditions +15°C, 29.92(3)'' Hg. Notably FCR, radalt, GPS, etc. was off so only height data should be baro/INS. Next step is to investigate non-ISA temps and pressures to see what happens.

F16 Ground-Air System Alt.trk

[Machalot]

On 1/3/2022 at 11:03 PM, Frederf said:

The crosshairs are short when self-tracking and long when slaved. At least I thought that's supposed to be the convention. I notice that TMS aft once from area track is long crosshairs but definitely not slaved.

Could be that long whiskers indicates inertial stabilization, which would include steerpoint slaved and INR.

[nitron]

I saw one of the posters was using the persian gulf map. I  ONLY get this there as well all the time in hornet and viper. Hope this is going to be fixed soon as this makes it very difficult to use visual tgt search. There is also a „bug reported“ thread here: 

 

[Wlasiuk]

How is this still a bug after two years? Have the same problem, JDAMs and CBU-103/105 in PRE mode go for the HUD marker instead of the TGP and the HUD marker and TGP are sometimes a few hundert meters off.

Solve this please, this bug makes the deployment of any INS guided weapons on the F-16 completely impossible.

[OldFlyer]

On 1/6/2022 at 2:15 AM, Deano87 said:

I’m doing this on my phone so apologies for the quality of the pic. But in the mission editor you select the Time and Weather tab and you change the QNH to 29.92.

 

I know this is an old post but if anyone else looks this up and comes across this post, I was experiencing the same issue as the OP and this might help you out.

I tried changing the QNH as suggested above but unfortunately that didn't do anything.

However, I then noticed the mission the random mission generator created for me had a date of 1950 (see top right of the screenshot in the quote above for location of date).

When I changed the year to 2010, the issue rectified itself.

[Machalot]

On 2/11/2025 at 4:33 AM, OldFlyer said:

However, I then noticed the mission the random mission generator created for me had a date of 1950 (see top right of the screenshot in the quote above for location of date).

When I changed the year to 2010, the issue rectified itself.

Sounds like INS drift.  If you're flying an F-16 in 1950 you won't get many GPS position updates to correct for INS drift.

In fact the INS had barely been invented by 1950.