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[REPORTED] A10 CCIP target elevation feed (Possible bug)


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Hi guys,

I noticed a weird behaviour with the ccip delivery. Regardless of what is your spi generator, when you create one, it looks like LASTE keeps the current steerpoint elevation for the delivery cue. Easy to replicate: fly at 3000ft to a wpt/mkp/stp that has an altitude higher than 3000ft, get a spi and still no drop cue as the computer will still be thinking that your target is above you.

 

From the manual at page 400:

 

A SPI is a 3D point in space that the systems use as a shared reference location to cue weapons, aim sensors and send over the datalink. This is a key component of the A-10C and helps you to locate targets with onboard sensors (Targeting Pod, Tactical Awareness Page, HUD, Maverick and AIM-9), then cue weapons and slave sensors to it. The default SPI is the steerpoint. Once a sensor has been set as the Sensor Of Interest (SOI), the sensor may designate the SPI. Once a SPI has been defined, the SOI can change without changing the SPI. The current SPI generator is always indicated in the lower left corner of the HUD. The system is always tracking a SPI with the current steerpoint being the default SPI (such as when the aircraft is powered). The exception is if the SPI is commanded to steerpoint but there is no valid steerpoint because the CDU is not available.

 

My work around is to create a markpoint on target and set that point as steerpoint, changing elevation data from DTS to manual (seems to be more accurate on targets in mountainous areas), but from my understanding that shouldn't be required as the spi, as 3D point, should also feed the target elevation for the release cue.

 

Any light on the matter would help!

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According to what you said, how do you explain the fact it is influecenced by current steerpoint altitude if it's supposed to be completely independent?

 

 

CCIP needs to know a target elavtion somehow, then uses as you said altitude/spd etch to calculate the pbil and impact point. Elevation data can be provided through different means, one should be SPI. Maybe you didn't notice as when you in the sim you always have a steerpoint select regardless, and if the alitude ot that point is close to the target one, you have a working system.

 

Reference for A10 usaf manual, TO 1A-10C-1 at page 1-434 reads:

 

The CCIP Mode uses EGI, CADC, target elevation, and stored

weapons information to compute the impact point for forward

firing and free-fall ordnance. It allows selection of various

modes, weapons, target elevations, and fuze times. A pipper

and reticle continuously display the impact point for selected

ordnance. The information is displayed on the HUD, and

includes symbology for CCIP guns, moving target indicator,

BATA display, CCIP bombs, Minimum Range Staple (MRS),

Desired Release Cue (DRC), and Projected Bomb Impact Line

(PBIL).

 

The only way that you can use CCIP without having to input target elevation is when you select the Radio Alt as altitude source, but it is not simulated as far as i know (only BARO, no Delta or Radio)

 

Source: TO-!A-10A-34-1-1 on page 1-25 (attached, just above LASTE 4.0 note)

 

As also the ED manual reports, the 10C usaf describes the SPI as: (1-391)

 

SPI.

The SPI is defined as the point in three-dimensional space that

the system uses as a unique reference for other functions, such

as weapons delivery, off-board transmission, and sensor slaving.

A sensor can define the SPI only when it is the SOI, but once

defined, the SPI is not necessarily confined to the SOI. For example, a change in SOI does not necessarily mean that the SPI

changes. A SPI is always present unless there is an error condition such as a failed CDU. Incorporation of Datalink allows

transmission of the SPI off-board. For a detailed description of

SOI, and SPI, refer to TO 1A-10C-34-1-1.

 

Obviously i don't have other publications out of the one i quoted above, hence why i am asking here if there is a correlation of the spi elevation and target elevation fed to the computers to calculate the PBIL, having observed a correlation in the simulator.

CCIP.pdf


Edited by Theduncanizer
Reference to manuals added
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I've never seen or heard of this problem before. What SOI are you using to create the SPI?

So if you are using the TGP to create the SPI you are saying it will be at the same elevation as the SteerPoint? If so it sounds to me your HUD is SOI. If using TGP, the SPI should be at GL as the TGP cannot create SPI in the air (IIRC)

 

Do you have a track so we can see what's going on?

 

 

As for your second post A10Yoda is correct CCIP does not need a SPI. CCIP gets the elevation data from DTS (which is also how SPI gets some of its elevation from as well)


Edited by Dagger71
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I've never seen or heard of this problem before. What SOI are you using to create the SPI?

So if you are using the TGP to create the SPI you are saying it will be at the same elevation as the SteerPoint? If so it sounds to me your HUD is SOI. If using TGP, the SPI should be at GL as the TGP cannot create SPI in the air (IIRC)

 

Do you have a track so we can see what's going on?

 

 

As for your second post A10Yoda is correct CCIP does not need a SPI. CCIP gets the elevation data from DTS (which is also how SPI gets some of its elevation from as well)

 

I made this track quickly. Wpt alt 6500 ft, tgt elevation 1650.

 

First pass: only ccip mk82 selected -> long

Second pass: tgp spi (confirmet on hud), DTS -> long

Third Pass: Markpoint created out of spi and selected as steerpoint/DTS-> long

Fourth pass: same as 3rd, but forcing steerpoint elevation of 1650 -> perfect hit

 

The three long impact are really close to each other with similar time of fall.

 

Notes:

I left TGP as spi generator for the last pass to show how the current steerpoint altitude influences the drops regardless of SPI.

 

The altitude that was set on the hud was the standard changing from DTS.

 

I would also like to clarify that i meant CCIP needs some elevtion data, usually taken from DTS, but that should be able to be overrided by SPI and it's confirmed is overrided by a manual stpt altitude.

 

Also worth of a note, TGP alt and standard altitude after changing from the DTS agree.

ccip.trk


Edited by Theduncanizer
typo
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As for your second post A10Yoda is correct CCIP does not need a SPI. CCIP gets the elevation data from DTS (which is also how SPI gets some of its elevation from as well)

 

 

Handshake from DTS

 

Sent from my SM-N975U using Tapatalk

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I would also like to clarify that i meant CCIP needs some elevtion data, usually taken from DTS, but that should be able to be overrided by SPI and it's confirmed is overrided by a manual stpt altitude.

 

 

 

 

 

There seems to be a bug on the replay as I cannot hear the moment the bomb is released.

 

So try flying higher (you are actually dropping from 1350 AGL) and a use a steeper dive angle. You can also experiment with 3/9 and 5mil CR which can be more precise depending on conditions.

 

CCIP is its own sensor and does not rely on any other reference point (MarkPoint, SPI or Steerpoint) to calculate the impact point. (You should always be using DTS elevation)

 

You can fly 1000 different flights and get 950 different impact points because in general CCIP is not pinpoint accurate but all things equal (speed dive, angle, wind, bearing of target) each pass should be quite close.


Edited by Dagger71
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There seems to be a bug on the replay as I cannot hear the moment the bomb is released.

 

So try flying higher (you are actually dropping from 1350 AGL) and a use a steeper dive angle. You can also experiment with 3/9 and 5mil CR which can be more precise depending on conditions.

 

CCIP is its own sensor and does not rely on any other reference point (MarkPoint, SPI or Steerpoint) to calculate the impact point. (You should always be using DTS elevation)

 

You can fly 1000 different flights and get 950 different impact points because in general CCIP is not pinpoint accurate but all things equal (speed dive, angle, wind, bearing of target) each pass should be quite close.

 

I will try and post the results. There is a thing i still cannot explain, and it's easily replicated. Fly at 3000 ft towards a waypoint, select mk82 profile and you will see the dotted pbil. ( also works with gun pipper). Now manually select an altitude from the ufc and set it higher than your current altitude, the ccip solution will disappear/get crossed. If ccip relies only on its own sensors, that shouldn't happen.

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I will try and post the results. There is a thing i still cannot explain, and it's easily replicated. Fly at 3000 ft towards a waypoint, select mk82 profile and you will see the dotted pbil. ( also works with gun pipper). Now manually select an altitude from the ufc and set it higher than your current altitude, the ccip solution will disappear/get crossed. If ccip relies only on its own sensors, that shouldn't happen.

 

 

 

 

I have never used Steer point elevation, I've always ever used DTS so I believe SP would only be used when in an area where DTS elevation is unknown but you get a precise elevation from an external source (JTAC or other).

 

Also to be more precise it uses EGI for elevation (but that's a different topic) but as long as you see DTS on HUD, you are good to go.

 

 

I'll try SP elevation later tonight just to see what is happening.

 

 

Now manually select an altitude from the ufc and set it higher than your current altitude, the ccip solution will disappear/get crossed.

Yes that will always happen and intended to work this way.

 

 

 

If ccip relies only on its own sensors, that shouldn't happen.

 

 

Yeah I think I was a bit unclear. It is its own sensor but relies on others (it needs data from multiple sensors to generate the impact point but not SPI MP or SP) when using DTS. All sensors work independently to a certain extant, but also rely on each other and the data cartridge(not modeled) as the Data gets passed through several onbord systems to be distributed to each system of relevance.

 

I've never actually seen the actual diagram ( and I do not think it can be posted in these forums), but it kind of goes like this: Data cartridge to DTS to CDU to CICU.


Edited by Dagger71
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I have never used Steer point elevation, I've always ever used DTS so I believe SP would only be used when in an area where DTS elevation is unknown but you get a precise elevation from an external source (JTAC or other).

 

Also to be more precise it uses EGI for elevation (but that's a different topic) but as long as you see DTS on HUD, you are good to go.

 

 

I'll try SP elevation later tonight just to see what is happening.

 

 

 

Yes that will always happen and intended to work this way.

.

 

 

 

 

 

Yeah I think I was a bit unclear. It is its own sensor but relies on others (it needs data from multiple sensors to generate the impact point but not SPI MP or SP) when using DTS. All sensors work independently to a certain extant, but also rely on each other and the data cartridge(not modeled) as the Data gets passed through several onbord systems to be distributed to each system of relevance.

 

I've never actually seen the actual diagram ( and I do not think it can be posted in these forums), but it kind of goes like this: Data cartridge to DTS to CDU to CICU.

 

 

 

Sorry i made a video but is before i red the comment. Even with a steeper angle still is inaccurate on dts until forcing the target elevation on the steerpoint.

 

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Sorry i made a video but is before i red the comment. Even with a steeper angle still is inaccurate on dts until forcing the target elevation on the steerpoint.

 

 

 

That's a real interesting video! Never really seen anything like it before. The fact you used active pause to demonstrate makes the differences obvious. I'll be playing around with it later tonight, cause right now I do not have an answer.

 

 

 

 

 

Let's see if anyone else can chime in and give their opinion.

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I might have found something useful. Every time we input a different value than DTS on the HUD, we are basically changing the Target elevation fed to the LASTE for its calcoulation (as theorised). Also the value limit is comparable, -1000 to 20560 in the game compared to -990 to 16380 in the A10A document, probably cause by different suite version). On the real airplane, there is a LASTE subpage in which you can select various tgt elev for different steerpoints, but that is not simulated in DCS so was kinda tricky to prove on documents. The question of the why the ccip is not spot on on DTS, but it becomes when forced (even leaving the tgt elev that appears once you select it) still remains. Maybe unaccurate terrain rapresentation in the sim on real dts data or vice versa? Also, although not necessary for operation, should a SPI feed tgt elevation (3d point, but in our sim we just use it to cage other sensors)? I think the latter could only be answered by a hog driver or a developer from ED..

ccip tgt elev laste.pdf


Edited by Theduncanizer
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I am sorry to have doubted you!! There is something wrong for sure.

 

I don't think TGP should be feeding any elevation data as it's really only getting it relayed from DT as well, and is just displaying it.

 

The fact that manual entry of the exact same elevation changes the accuracy does not smell right.

 

I'll be playing with this over the next few days for sure.


Edited by Dagger71
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Not a bug. Improper settings from digital pilot.

 

QNH for the hog not QFE..and I would switch to radar..or even delta since you probably QFE'd your airfield you took off from.

 

Sent from my SM-N975U using Tapatalk


Edited by A10Yoda
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Not a bug. Improper settings from digital pilot.

 

QNH for the hog not QFE..and I would switch to radar..or even delta since you probably QFE'd your airfield you took off from.

 

Sent from my SM-N975U using Tapatalk

 

Hi A10 yoda, all the test were filmed flying QNH. The behaviour you quote is correct, but the ALT SCE switch apparently is not implemented in the DCS model(It;s an old post but i din't see it in any changelog, if you have any info would be amaing:https://forums.eagle.ru/showthread.php?t=82199 ).

 

 

I made another video trying out your suggestion:

 

 

1st drop, inducing a qnd error setting a random value

2nd drop, setting the correct qnh

3rd drop, selecting DELTA from the ALT SCE switch

4th drop, selectin RAdio from the alt sce switch.

 

All impact are on the same spot, showing all these parameters do not affect the DCS model (contarly to the real airplane behaviour)

 

For the 5th drop, i used the tgp to gain correct target elevation and input that value in the LASTE via the HUD, the solution moved exactly on the previous impacts, same spot where the 5th bomb impacted (so the ballistic as expected remains unchanged).

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Well then maybe, but I would do an additional test unpausing the sim to see if some how the active pause it is effecting the computed impact area.

 

Or more-over reset the SPI after resetting to QNH with delta selected. So after TGP SPI, reset SPI back to steerpoint with new settings

 

Sent from my SM-N975U using Tapatalk


Edited by A10Yoda
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I didn't make any spi to avoid possible sensor interaction faking results, i just red the elevation, tgp remained in Atrack. All i had set was steerpoint as spi. I didn't make a video this time, all the results match the hypotesis. Releasing active pause didn't generate any change in simbology, all the drops were offset until target elevation is forced in instead of dts.

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I think you may just be over estimating the accuracy of the terrain database. Since the target is on such varying terrain, definitely you’ll want manual HOT. Ideally you’ll be working with a jtac/afac or have been able to use tgp from a distance to get an actual HOT before getting this close.

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I think you may just be over estimating the accuracy of the terrain database. Since the target is on such varying terrain, definitely you’ll want manual HOT. Ideally you’ll be working with a jtac/afac or have been able to use tgp from a distance to get an actual HOT before getting this close.

 

That might be the issue, but if you try it, you just need to switch from dtc to HOT if you create a markpoint on the target, select it as steerpoint, and It works perfectly, even without the jtac giving you any accurate number.

 

If the dts was not accurate the workaround i mentioned shouldn't work..

 

 

The other question is, IRL i know airplanes like the av8 feeds target elevation from the most precise source (tgp for example when you create a lock), shouldn't the A10 do the same?

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When you switch to HOT, the elevation is latched from the current steerpoint. In the real jet it definitely will use tgp spi elevation to set HOT when available, but there was some debate of dcs had modelled that (the guess is no).

 

How did you create your mark point? If it is via the tgp then you do get the tgp ranged elevation (I believe with laser if it was on when you created the mark point ), thus a tgp quality elevation was latched to HOT when you left DTS. Try inspecting the original steerpoint’s altitude in the cdu to the altitude if the mark point.

 

HOT is always more accurate than DTS, and thus preferred when you have time to configure it.

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Well I’m just going to throw a dart then: the bug is the accuracy of markpoints set from the hud. AFAIK they should be using elevation from the terrain database, but it wouldn’t surprise me if dcs uses the model geometry and thus gets elevation as accurate as the tgp does.

 

Fun thread, thanks for bringing it up!

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Well I’m just going to throw a dart then: the bug is the accuracy of markpoints set from the hud. AFAIK they should be using elevation from the terrain database, but it wouldn’t surprise me if dcs uses the model geometry and thus gets elevation as accurate as the tgp does.

 

Fun thread, thanks for bringing it up!

 

That is the part that bothers me so much about this. If there is some sort of bug where the elevation (or possibly even vector data!) gets called wrong in normal operation but is exact during manual entering, it should affect every single module in game.

 

I've never heard anything like this and yet if you watch his replays, the discrepancy is very obvious. It goes from missing targets to getting pinpoint LGB precision just by manually entering HOT even if you are actually entering the EXACT same elevation!!!!

 

 

 

I found another thread from 2014 and still cannot believe (or probably forgot if I ever did know this) its been this long since it's been around.

 

 

https://forums.eagle.ru/showthread.php?t=118975

 

 

So yes manually entering HOT will be done each and every time, even if its the exact same elevation as found from DTS. Doesn't make sense, definitely a bug.

 

 

 

 

 

Also can someone confirm this exhibits the same issue on the PG map? If it does then it's a bug with the DTS logic, if not then its possible one of the Caucasus map layers (vector or raster) is actually off.

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