correct as is A-10C II - A-10C II - TGP has problems locking and following targets

[NightMan]

I'm not sure if this is really a bug as I don't know how it works in real life, but it surely appears to be.

This happens in the A-10C II but not in the A-10C.

In the A-10C II the TGP has enormous difficulties in locking and following targets, but in the A-10C it locks and follows very easily.

The planes may be a little different, but aren't the TGPs the same?! That would mean the behaviour is wrong in one of them.

A-10C - TGP has no problems in locking and following targets.zip A-10C II - TGP has problems locking and following targets.zip

[Yurgon]

21 hours ago, NightMan said:

In the A-10C II the TGP has enormous difficulties in locking and following targets, but in the A-10C it locks and follows very easily.

Thanks for the tracks!

I've looked at all of them, and honestly I don't know what difference it is you're trying to show. Your flying is a bit different between the tracks. The A-10C II tracks in some cases have a bit of masking, clearly indicated by the "INR-P" and "M" indications on the TGP page, but easily re-acquire the target as soon as you're unmasking the TGP. Looks to me like the old A-10C would have done exactly the same if you had just tilted the wing down toward the target a little, like you did in the A-10C II track.

Note that in both aircraft/modules, the TGP uses a fixed masking profile ("M4"), which may extend a bit beyond what can actually be seen and targeted by the TGP, depending on the weapons loaded. So just because an object is visible in the TGP doesn't mean the TGP can actually and realistically track it.

If you can create 2 tracks that are absolutely identical in terms of flying and pilot input, but that show different TGP behavior, that would help narrow it down.

So far, it looks to me like some very minute differences in your cockpit actions cause some rather minor changes in TGP behavior, which is totally normal and would be the same in both modules.

Note, I'm not saying A-10C and A-10C II are absolutely behaving the same; I'm just saying that with the tracks you provided, I don't see the difference.

And side note, why are you always switching the TGP to both Laser + IR Pointer in daylight conditions? Seems a bit unnecessary, but shouldn't change the outcome. I'm just curious.

[NightMan]

You are right.

I just reused the track from another topic.

I will make new ones ASAP and provide them.

[NightMan]

I suppose you are correct.

Attached are a couple of new tracks. The behaviour is the same with both planes, although disappointing.

I think the problem occurs when we try to select a target "sideways".

In the first tracks I uploaded, with the A-10C II, I used the HMCS to find the target, and so the TGP had the target to its left, therefore "sideways".

With the A-10C, I had to point the nose towards the target in order to find it.

This time I built a mission with one waypoint very close to where the vehicle would be and at ground level, so that I could just make that WP a SPI and slave the TGP to it, which allowed me to fly in the exact same conditions — straight line parallel to the target.

What I found is that "sideways" both fail in locking and following the target.

If this is the correct behaviour, then, please excuse me and archive the topic.

But I ask you

to

please check into this, because it doesn't make sense in having to face the TGP

head-on

towards the target so that we can lock it

— i

t renders the TGP useless.

TGP has problems in locking and following targets.zip

[Yurgon]

12 hours ago, NightMan said:

What I found is that "sideways" both fail in locking and following the target.

Yes, this is to be expected.

In both tracks, the TGP shows "INR-P" and "M", indicating that it is in inertial point-track and masked.

In DCS, we have a single masking shape ("M4"), regardless of our loadout. In real life, the masking shape would change according to the loadout. This is not simulated in DCS.

Considering that outside of the TGP, both a bunch of bulky AIM-9Ms as well as the big ALQ-131 and ALQ-184 ECM pods can be loaded, "our" masking shape has to take all of these into account.

You also need to understand that the TGP is not just one sensor. The head of the TGP contains multiple sensors in slightly different locations, so it's quite possible that the CCD camera can clearly see an object, but one of the other sensors might actually be masked by stuff hanging from the jet on the other pylons.

As far as I'm aware, tracking is done via digital image processing, so if we can see an object on the TGP page, I assume it should be possible to track it, which would mean that DCS got it slightly wrong. But don't quote me on this, as I'm not an expert regarding the Litening's inner workings.

When you check the TGP's situational awareness cue (the single white dot that represents where the TGP is looking relative to where the jet is pointed), you'll notice that in your tracks, the SA cue was always near the edge of the TGP display, meaning it was looking at a very shallow angle, which in turn means that masking by anything hanging next to the TGP is rather likely.

So, long story shot, in order to see and track objects sideways, you need to unmask the TGP, and thus need a steeper angle between the TGP and the object in question. Either get closer, or climb higher. If the tactical situation requires you to fly like you did in the tracks, then either track manually, like you did, or change the position of your aircraft to put the target into the forward quadrant where the TGP has no obstructions and thus no masking from your own jet, and make use of your wingman so one of you always has tally on the target (obviously doesn't work with AI wingmen in SP, but this is great practice in MP with human wingmen).

In essence, there may be a little bit of a discrepancy between DCS and real life (but honestly I'm not sure if that's even the case), but all things considered, DCS has basically the same limitations that pilots also have to deal with in the real aircraft.

[jaylw314]

To expand on @Yurgon's comments, on the 3/9 line the TGP has approximate limits IIRC when moving down from the plane of the wings:

< 30 degrees - unable to lase

< 25 degrees - unable to POINT track (switches to INR-P)

< 20 degrees - unable  to AREA track (switches to INR-A)

So if you want to track a target on your 3/9 line, you'll need to take that into account by banking away from the target.  If you want to be in wings level flight and still see the target, it needs to be at least 30 degrees down, which means at a slant range of 5 nm you need to be at least 15,000' AGL

Edit: corrected below

Edited November 26, 2023 by jaylw314

[Yurgon]

25 minutes ago, jaylw314 said:

< 30 degrees - unable to lase

< 25 degrees - unable to POINT track (switches to INR-P)

< 20 degrees - unable  to AREA track (switches to INR-A)

Oh wow, that is awesome! I never knew there were some numbers, even when they're just approximations. Now I need to find a way to memorize them.

Edited November 10, 2022 by Yurgon

[jaylw314]

2 hours ago, Yurgon said:

Oh wow, that is awesome! I never knew there were some numbers, even when they're just approximations. Now I need to find a way to memorize them.

 

LOL, they're not official, they're just my eyeball measurements  They also change as the FOV moves further aft.  One day I'll map out a spherical depiction of the TGP FOV and functions, but it will not be today

Edited November 10, 2022 by jaylw314

[NightMan]

I didn't know that.

Very interesting and useful. I will make some tests at higher altitudes; 5nm is WAY too close, especially when a Tor or an Osa are involved, so, if I want to be at let's say 7.4 nm I will need to be close to FL20.

Thank you Sir.

Edited November 10, 2022 by NightMan

[jaylw314]

On 11/10/2022 at 9:51 AM, Yurgon said:

Oh wow, that is awesome! I never knew there were some numbers, even when they're just approximations. Now I need to find a way to memorize them.

 

Well, color me wrong, but I just did some testing on the TGP FOV, and it appears my memory is incorrect.  As far as I can tell, the FOV of the laser is identical to the FOV where AREA and POINT track work now.  I could swear I recall some difference before, but oh well.  I've got numbers, but how do you draw it in a spherical map?

The following is the range of elevation (in degrees) of the camera being masked or obstructed with inboard armaments loaded.  I didn't include the bearing 60 value since the sidewinder nose doesn't really obstruct visibility too much:

Bearing	Min elevation	Max elevation
90	5	90
120	5	90
150	-32	90
180	-52	90
210	-35	90
240	0	90
270	-6	25
300	5	30

 

The following is the range of elevation of the laser and video tracking being masked:

Bearing	Min elevation	Max elevation
30	-15	0
60	-21	36
90	-23	90
120	-20	90
150	-32	90
180	-50	90
210	-32	90
240	-35	90
270	-37	65
300	-34	50
330	-5	27

 

Note that these are in level flight about 240 KIAS, so they may be different with a different AOA.  All the elevations are about +/- 2 degrees.

Don't forget the area off the nose that suffers gimbal lock (not the same as gimbal roll).  It's about 5 degrees below the boresight circle, and about 2 degrees wide.   You can find it by slewing the TGP through that area.  When you see the edges of the video image rotate through 180 degrees, you'll notice the TGP diamond actually does a circular sidestep around that area.  Don't pull any target through that location or the video tracking will be lost.  

Edited November 12, 2022 by jaylw314

[Yurgon]

4 hours ago, jaylw314 said:

The following is the range of elevation (in degrees) [...]

Wow, that is amazing! How long did it take you to take all these measurements?

I'm just having some trouble figuring out what the numbers mean exactly; can you give me some pointers?

Was that with a TGP on station 2 or station 10, or does that not make any difference?

Bearing, is this relative to where the nose of the jet is pointed? So Bearing 90 is to the right aka the 3 o'clock position, bearing 180 is 6 o'clock or aft of the jet, and 270 is left aka 9 o'clock, correct?

And how about elevation? When the TGP is looking straight ahead, that's 0 degrees of elevation, when it's looking up, that's a negative elevation, and when it's looking straight down, that's 90 degrees, correct?

[jaylw314]

46 minutes ago, Yurgon said:

Wow, that is amazing! How long did it take you to take all these measurements?

I'm just having some trouble figuring out what the numbers mean exactly; can you give me some pointers?

Was that with a TGP on station 2 or station 10, or does that not make any difference?

Bearing, is this relative to where the nose of the jet is pointed? So Bearing 90 is to the right aka the 3 o'clock position, bearing 180 is 6 o'clock or aft of the jet, and 270 is left aka 9 o'clock, correct?

And how about elevation? When the TGP is looking straight ahead, that's 0 degrees of elevation, when it's looking up, that's a negative elevation, and when it's looking straight down, that's 90 degrees, correct?

Oops, yes the TGP was on station 10 (the right side).  Presumably on station 2, the left and right FOV would be reversed.

You are correct on the bearing, 0 is 12 o'clock, 90 is 3 o'clock, etc.  I wasn't sure if 'bearing' or 'azimuth' was the correct terminology

For elevation, 0 is at the horizon, 90 is straight up and -90 is straight down.

Of note, for the camera, FOV is unobstructed from about 330 to 060.  I conflated the camera being masked (no video feed) and obstructed (video feed but blocked by the plane or weapons).

For the laser FOV, I was surprised to confirm that while there are areas to the right masked by the sidewinders, from 030 to 090 the laser is unmasked again above the sidewinder.  Likewise, POINT and AREA track are lost and revert to P-INR and A-INR, respectively, if you roll the target through that area.  Also surprisingly, from 270 to 330, the laser is also unmasked above the fuselage.

I confirmed that the POINT and AREA tracking FOV is identical to the laser FOV by rolling upside down and using active pause, then checked that POINT and AREA tracking worked in the same places above the plane of the wings as the laser.

I never thought to try this with the A-10C because there was no way to verify what angles the TGP was looking at, but I realized with the HMCS, I could look at the TGP diamond and use the HMD pitch lines and helmet bearing.  A couple points I had to guess the elevation because the pitch lines only go up and down to 55 degrees.

I need to think of the best way to depict this visually, but I'm not sure what that would be

Edited November 13, 2022 by jaylw314