TGP loses target tracking

Hey All,

I took a bit of a break from DCS between version 1.2.2 and just started back with 1.2.7. Anyways, I am finding that the tgp is losing tracking even when I engage point track or inr-p and make a simple turn to the target. The behavior feels different from earlier versions.

For example, I have a target at my 3 o'clock and engage inr-p and start a turn towards the target. By the time the target is at my 12 o'clock the tgp has lost tracking and I have to acquire by slewing again. Usually the target isnt too far out of tgp sight but i usually have to slew to re-acquire. There are time when i have engaged point tracking and have the same problem.

This is happening more often than not and is very frustrating and makes gun runs a nightmare.

What am I missing here?

Haven't noticed that, but then I usually make my target SPI on top of tracking it. That way even if your TGP looses it, you can easily slew it back to target by pressing (IIRC) CHINA HAT FWD LONG.

I noticed that, but I thought it was normal. AFAIK in inertial track mode there will be some significant error.

Also the TGP thinks it is pointing at the ground behind the target...that's where it points for me after a long bank in inertial mode. I think this means it's off by more when you're at low altitudes, because of the angle.

just slave TDC onto TGP and make it SOI, then put TGP to standby. Easy peasy..

you are doing TMS up long arn't you??

AFAIK that happens when the TGP is masked, as indicated by INR (Intertial). "Masked" doesn't necessarily mean that the CCD image on the TGP screen doesn't show the target, but given the aircraft's current load-out, some of the TGP's sensors are probably masked.

OTOH, point mode tracking is done by optical means, isn't it? So I'm not sure if the above is correct, but I think there's a strong correlation between INR and loss of tracking.

If you are in INeRtial mode, you have lost track which is why the pod switches to INR in the first place. It should be pointing to the same position in space though so, unless the target has moved, it shouldn't be too hard to reaquire it.

They have changed the TGP It will and moves on me all the time no matter what I do.

Here is a small track. 2nd run on target

you are doing TMS up long arn't you??

This shouldn't make any difference to stabilization?

Are you making smooth, gentle turns? Do you make your turns towards the wing with the TGP on it to prevent masking?

Here is a small track. 2nd run on target

GIMB ROLL seems to be the important indicator here. :smilewink:

http://forums.eagle.ru/showthread.php?t=59310

http://forums.eagle.ru/showthread.php?t=108573

When the TGP is in INR mode it is masked (can't see the target), there will be a M on the TGP MFD and the HUD, you won't be able to track the target as the targeting laser (not the ccd) is masked.

Are you sure that point mode tracking uses a laser? I couldn't find any reference to this in the manual.

The pertinent chapter seems to be the one on the TGP...

AN/AAQ-28 Litening AT Targeting Pod

 

The Litening AT targeting pod incorporates both a daytime Charged Coupled Device (CCD) TV camera and a Forward Looking Infrared (FLIR) camera that are used to acquire and track targets day and night. Also built into the pod is a laser designation and ranging system and an infrared pointing device (IR Pointer). The pod can also detect laser illumination and track it in the Laser Spot Search and Laser Spot Track (LSS/LST) modes.

... and the TGP Air-to-Ground (A-G) Page:

Point Track Box. When the TGP is in POINT track mode and it has detected enough thermal or visual contrast to track an object/target. A box (container) will be centered on the object/target being tracked. If POINT track is lost, the box will be removed.

AFAICT, the laser has nothing to do with point track mode. :smartass:

^

One way to test, keep laser in SAFE mode and see if you can point track a target.

Thanks for all the feedback guys.

I think I am doing things correctly as far as engaging point track mode and TMS FWD Long, Its just that the TGP seems to lose the target so easily during some turns.

I will try to do a track to illustrate.

I think I will also delete my TM Hotas WH in-game profile just to rule that out as well.

M = Masked (on the HUD), L for Laser track, technically the CCD is only half of the tracking system, It needs to see the laser to gather Height/Range data. This is how rangefinding and hence tracking works.

 

Without the Range/Height measurements the CCD is capturing a 2-Dimensional Image. The Laser Rangefinder adds the essential 3rd dimension required for target solution, just because it is not mentioned in 1 paragraph of the manual does not mean it is not in use.

 

http://en.wikipedia.org/wiki/Laser_rangefinder

I tend to disagree more strongly the more you write.

Firstly, optical tracking doesn't require range information. The DCS Ka-50 and its simulation of the Shkval targeting system is a solid indicator of this. Of course, this doesn't mean the Litening TGP necessarily uses the same kind of tracking. It just means that optical tracking doesn't require a 3D position.

Secondly, AFAIK the SPI is in fact a point in space and therefore a 3D point. Still, this doesn't mean that laser tracking is the only conceivable way for the A-10C's systems to know the SPI's exact 3D coordinates. Hint: Digital Elevation Database.

Thirdly, instead of hinting why your position on the matter might be correct, could you point to specific data like chapters in the DCS A-10C manual, real world documentation or some such? I don't think that you're necessarily wrong, but you seem to contradict the information that is available to me, yet you provide no data to back up your position, that's why I have a hard time accepting it.

^

One way to test, keep laser in SAFE mode and see if you can point track a target.

Haha, yeah, that's a simple way to test the theory. :)

Good in theory but will putting the laser in "safe" shut down the internal functions of the lightning pod or just deny a lase when requested by the DSMS?

Oh come on. If you know how the system works, provide a reference to the manual (or state very precisely and specifically why the manual is wrong).

Laser status. What is displayed in this field is determined by the setting of the laser switch on the AHCP.

 

[...]

 

When the active designation device is firing, the display field on the TGP display and on the HUD will flash at 2 Hz. When it is not firing, it returns to steady.

 

If the TGP line of sight is masked by the aircraft, “M” is displayed in this field to the right of the laser type. If masked, the laser will be unable to fire.

So, what's the "L" look like while point tracking a ground target? QED. :smartass:

I think I am doing things correctly as far as engaging point track mode and TMS FWD Long, Its just that the TGP seems to lose the target so easily during some turns.

 

I will try to do a track to illustrate.

My guess would that the source of the problem is the TGP being masked and/or GIMB ROLL. But a track would definitely help narrow it down. :thumbup:

The targeting pod doesn't use the laser to track objects in point mode. The way it calculates the distance to the target (and therefore shows on the TAD) is by using its built-in digital terrain elevation database. If the pod knows where it is over the terrain (location and altitude info from the aircraft) and the angle that it is looking, it can calculate where that line of sight intersects with the terrain. I agree with Yurgon on this one. :)

Are we sure this isn't just a small amount of pilot error? I often find, especially the further I am from the target, that by the time I have (for argument's sake) halved the distance that the TGP is off by some amount - I always assumed this was because I couldn't be as accurate as I wanted at longer ranges, and as the distance closed this error was multiplied?

We are discussing part of the A10c payload, not black shark avionics in this case. The exact nature is most probably classified. Maybe an email to Northrop Grumman will clarify how it works, maybe not.

 

[...]

I think we should clear up a few things, because there seems to be a misunderstanding here.

You are saying that TGP target tracking in the A-10C depends on a laser, right?

I'm saying that target tracking is done with optical means. None of the links you provided seems to contradict this point. In fact, you haven't provided a single bit of information to prove that the Litening pod uses a laser for target tracking.

However, I never said there's no laser or rangefinder used in target ranging -- because we were talking about tracking, not ranging.

I have a basic understanding of what a laser rangefinder and a laser designator are and how they are used. It's just that, to the best of my knowledge, they have nothing to do with how point mode tracking works.

The A-10C manual gives some very solid indications that the tracking is done by optical means. If the laser being masked is the reason that INR tracking loses the object, could you provide solid and pertinent data?

Regarding the digital elevation database, I didn't make that up. It's all in the manual, just go take a look at it. Other than a giant misunderstanding, I can't see any reason to bring up missile systems that have little (or nothing) to do with the A-10C and argue how it would be a bad idea to fit some of that stuff into the TGP.

GIMB ROLL seems to be the important indicator here. :smilewink:

 

http://forums.eagle.ru/showthread.php?t=59310

 

http://forums.eagle.ru/showthread.php?t=108573

i was wondering was GIMB ROLL meant. It's not mentioned in the manual as a far as I could tell.

I think this explanation in the thread I linked is pretty good:

As you roll your wings, there is a slip ring in head of the TGP that allows the sensor ball to roll to keep the horizon level. This keeps the picture on your MFD level and ground stabilised. The head can rotate through a certain number of degrees in any direction before it hits the stops and must 'de-roll' - I don't remember the exact figure off the top of my head.

And "GIMB" is most likely just short for "GIMBAL".

I'm saying that target tracking is done with optical means.

And you're absolutely right. The point track mode uses the same kind of technology that the Maverick missile uses to track an object. Contrast in the image feed from the sensors can be defined by the pod as an "object" in the image and tracked.

Probably not too different from the way your smartphone can recognize a persons face when you use the camera

Sigh.. I know Im right..

 

( PERTINENT DATA: LOAD UP A10c and TRY IT! )

 

If you get a point track on a vehicle (indicated by the small square box inside the crosshair of the TGP MFD and then bank the plane untill the L (laser) indicates LM (laser is masked) you lose the track (the little box indicating point is tracked vanishes) whereas the image is still on the MFD.

 

This is highlighted further if you attempt to track a moving target.. you will see it drive off the image.

 

You are right in the sense that point track utilizes same technology as the missile. But just as the missile relies on RANGE TO TGT being verified before it can be fired, so does the TGP for initial track.

 

In a sense there are two separate functions of the laser.. one is as a "Designator", the other is as a "Rangefinder". The rangefinder is in use when the TGP is active. The designator only fires when the pilot or DSMS tells it to. Im speaking of the rangefinder, not the designator, dont get them confused.

 

The reason for this reliance I have already stated, as with the MAV Missile and the TGP, without accurate RANGE data, the only info gathered is a two-dimensional image. The MAV needs to know how far away it is from the target so that it can be fired within "RANGE" (indicated by the range ladder on the HUD). The TGP needs the range data to track the point in three dimensions so that accurate GPS coordinates can be generated AND so that motion can be predicted in the Z axis (motion in the Z axis cannot be accurately tracked in 2 dimensions as the only indication of it in 2D space is the target getting larger or smaller as it travels towards or away from the camera).

I've been trying to stay away from these forums recently lest I go totally mad, but by god it's a long time since I read as much rubbish in one thread, so I can't not get involved.

No, you are NOT correct. You have some serious and fundamental misunderstandings and misconceptions regarding not only the LITENING ATP but also weapons and aircraft systems and their operation in general.

Yurgon and others are, mostly, correct. You need to go back and actually learn how this stuff works rather than making assumptions.

I know this will come across quite harshly, but frankly I can't think of a more pink and fluffy way to say it.

Yurgon and others are, mostly, correct.

OMG OMG OMG. I will mark this day in the calendar and celebrate it every year from now on, for I never thought I would read such a thing coming from you. :D

OMG OMG OMG. I will mark this day in the calendar and celebrate it every year from now on, for I never thought I would read such a thing coming from you. :D

Hehe, I was definitely waiting for Eddie to chime in as well. Seems it may have been in vain though :megalol: