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[OLD BUG REPORTS] Cleaning and Organization of old posts


RAZBAM_ELMO

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sorry for that, and sounds good for this devlopment, but actually there is a little bug on the red radio :

 

 

 

if i put 124.000 on scratch pad and select channel 09 on roller ( 126.000/ for example)

 

 

I turn the selector on Manuel, 124.000 is displayed on repeater display( no problem)

 

 

but if I switch selctor on Preset position with roller on 09 ( 126.000), the repeater display still 124.000 and my radio is still on 124.000)

 

 

I need to turn roller to 08 and back to 09 to display 126 on the repeater display

 

 

and same if i come to P position to M position, i need to move roller to display 124.000 on repeater....

 

 

 

regards

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i try restart process after Negativ G's flame out.....impossible...normal and sec restart process does'nt work...

 

 

normal and sec restart works fine after volontary flame out, but not after neg g's flame out.

 

 

 

ok i puush the limit's, but this aircraft can restart after that (?)

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i try restart process after Negativ G's flame out.....impossible...normal and sec restart process doesn't work...

 

normal and sec restart works fine after voluntary flame out, but not after neg g's flame out.

 

Yeah, the restart behaviour changed around May 2018 and has never been resolved.

 

For Info: The old bug thread was moved to the "resolved bugs" section,

 

https://forums.eagle.ru/showthread.php?p=3417206#post3417206

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I'm not sure if it's a bug or normal, but it seems strange to me.

 

When I select air-ground canon (CAS) and then select forward special mode to have the air-ground canon reticle, at first it activates air-air boresight special mode instead.

 

I have to push down special mode switch, and then push it forward again to obtain the air-ground reticle for the CAS.

 

Here a track.

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Hello, I finally found time to have a look to this, so let me try to explain quickly, hope to give you and any other user that want to understand and not just play, more valuable information.

 

The RDI in TWS goes in single bar scan and follow the target with elevation.

So, it's true that raw data is limited by the number of swipes.

But let me explain a bit more how radar works and what has been simulated on the raw data elaboration.

 

Any raw data is processed, part of it, is a matching algorithm that will try to "old" contact with latest swipe contacts. If a match is found the target is confirmed to be the same and this happen any time if the contact is in TWS or not.

There are many others implications related to target signal, position, attitude, ground, interferences, position in the antenna cone, identification, Mirage position... some of them are classified some has been understood and reproduced.

 

 

But two of them are something you should consider in your analysis and video.

-One has been found, predicting target next position to facilitate the matching process, bear in mind that this prediction could also result in target out of radar frustum.

-Another one, the most important was not considered here, it's that every contact is ground stabilised, and that's I beleive is the results of the smoothness you see.

 

So everytime we draw a contact on VTB or HUD, this simple 2d coordinate, is the result of the computation of latest contact data plust Mirage position, antenna position, target attitude, prediction and ground stabilisation, this is why if the contact is lost or is out of cone it's still drawed with smoothness.

 

I personally think that Thales, few years back... did a miracle using analog and few digital components and here we are doing not bad into reproducing that with our possibilities (limited software computation and classified informations).

 

Let me add that without all of these you will probably have a WW2 radar.

If you want to know more on the subject just contact me on Discord.

Bye!

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Can we have an official advice on this problem please? I have the same bug

Thanks!!

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In DCS I fly jets with thousands of pounds of thrust...

In real life I fly a humble Cessna Hawx XP II with 210 HP :D

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Strange, for me it's just the CAS, as the other A/G weapons get the right A/G mode with first push forward of Special mode switch. (ccip or ccrp)

 

If you select on PCA, make your settings, then go directly into attack mode yes.

 

But if after making the settings you go back into memorised mode with WEAPON SystemCMD AFT, when you go into attack mode you have the same bug as with CAS :smilewink:

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Hi Elwood and thank you for the reply.

 

I understand what you said and it sounds logical for me.

While the radar is sweeping in 1 bar, it is still sweeping. Even it is predicting.

So the HUD box may still be smooth, but it can only be spot on when the radar sweeps over the target.

So lets come back to my video:

From 0:29 to 0:39, it may be correct that the box is smooth, as the target is nit maneuvering and exactley there where the computer predicts it.

But whats about 0:39 to 0:49? As the radar is stil sweeping, the target is maneuvering and the computer can't predict that, the box must cleary move away from the tracked aircraft.

Or please explain me, how the target can be tracked 100% smooth and correct, while the radar is not permanently looking at it?

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It would be for many easier to understand a radar operation if they would go or when it is dark and take a flashlight with them. Start sweeping front of them in a120/60/30 degree arc at steady pace and think whole what they see if there would be something moving there.

 

Everyone would notice that 120 degree sweeping would be slowest, like if it would take 4 seconds to go from left to right (120°/4s = 30°/s) so every object in the scenery is visible only once every four seconds (for argument sake, let's think the flashlight beam is the 1.5° wide, and to give a context for that, if you extend your arm front of you and put thumb up then your thumbnail area is about 2-2.5° of your field of view). So going to 60° arc means you are now seeing everything every two seconds. Going for 30° is once a second.

Now, how many has been in disco and remembers those strobe lights flickering like 5 times a second?

 

If you would be in fist fight in that, you need to do a lot of predictions where the other person is so you can hit them. And if other does slight movement, it will throw off your capability to predict where they are.

 

Now, a radar that is scanning while tracking, needs to build a track. Track that is updated Everytime the radar completes its scanning pattern (left to right + X times as set by bar value. So example 120° arc in 4 seconds and 2 bars means it takes 8 seconds to create update) in that time the update is done the target can move where ever wanted and radar doesn't know anything where it is between that update time. Now if the same target is detected between two bars, it is marked as new contact so it becomes a ghost. And there are own ways to avoid that, so just to keep it simple. But between the updates radar tracking system generates two "gates" for each contact. One gate is the prediction of future position where the target will be in next time when radar "lights" it. And this gate starts big, as the target velocity, vector and distance are not accurate enough with one update. Typically it takes 3-4 updates to get target vector and speed accurately enough, but range is faster to get with 1-2 updates (rarely two). That gate prediction takes so on lots of time 4s * 3-4 = 12-16 seconds. And that is when target moves straight and staying in same speed. Now you have very good prediction where target will be in next X times of updates. And lets say you want to shoot a bullet (not missile) at it that takes 25 seconds to fly there, it requires to know very well where target is so it can hit it. A very complex thing to do at long range, but easier if it would, lets say 2 seconds to hit it.

 

That targeting gate is the intercept point where you need to aim to intercept the target. And it goes smaller and smaller (more accurate) on each update when target doesn't alter vector or speed. But if it does, that gate never gets smaller, it is never accurate as the position where it is heading on each update is changing and now your prediction of intercept point is huge, a total sum of all the previous calculated intercept points.

 

That is why there is a second gate, a "possibility gate". That is the gate that is calculated based all the information there is about the target, and that is used to generate gate that what are all the possibilities where the target can go between updates. So that is huge gate. And that is used when target lock is lost, as that gate area is then quickly scanned to find it again. It is like if you would be waving flashlight and person walks in park and suddenly he vanish, you know that person can not have gone far from last know location, so you start to wave flashlight in the general area of last seen position and where it might have gone in that time, like behind the tree next to him or the bush just little forward of last known location.

But you will give up that you have lost him and you were tracking him as you are waving light around him now, even if you don't see him.

 

The radar scope like the TWS smooth tracking is just a interpolation based prediction that where the target is between updates. It should get accurate if target velocity and vector doesn't change, but any slight changes should cause inaccuracy and only be accurate when radar updates target again, after it is again lost in accuracy. So someone doing a spiral toward you and you can't get anything from it really. Or two targets snakes at you in close formation (crossing each others flight path) and you can't build a track nor predict where target will be between updates. So if you try to shoot at them, or even show a target box on it, it will miss a lot, or you can't even track them.

 

Targets merging and separating causes radars lose the track. And that is easy to do when two targeting gates merger or they operate inside the same probability gate. Your Targeting data is invalid. And radars has problem to detect close formation flying targets as radar resolution ain't enough to detect them. Low bandwidth radar (L band) can have hundreds meters to thousands, and high bandwidth can have tens of meters to few. So if you can fly in close formation like 5 meters from each others in distance, you become invisible to radar or you become too look like one big target. And 3-4 fighters can be merged as one against X-band radar in nice close formation.

 

Now make that formation to change vector, speed and you can't get a valid taken data. Make the flight separate and merger, and track is lost. A flight of 3-4 fighters can approach a other fighter and deny then getting a weapon grade lock.

Trying to guide a missile to such target means it will fly at intercept point to where there are no one.

 

Add there all ECM functions that are changing the distance and position and speed of the target (group) and you will see in HUD how the targeting box will jump and lock is lost etc. And sooner than later, you are merged with multiple fighters and maybe get out one or two but rest gets you.

 

If the radar prediction box is smooth constantly in DCS, it is limitation in the radar operation in the DCS. As right now there is big problems in the radars as all seems to operate like a STT lock, even with a TWS.

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Please acknowledge the good values:

- radar beam is 3° wide.

- scan rate is 100°/s

- TWS is 1 line, 120° max so 1.2s refresh rate maximum. If you lower the scan width to 60° you guessed it, 0.6s.

 

Let's imagine the target is traveling at 300m/s.

If the target moves from 360m, at 18500m would it be obvious in the HUD target box ???

 

For the full 4 lines search pattern we can round up to 5s to scan the full volume. But no TWS here, no velocity vector, just contacts with closing velocity.


Edited by jojo

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Please acknowledge the good values:

- radar beam is 3° wide.

- scan rate is 100°/s

- TWS is 1 line, 120° max so 1.2s refresh rate maximum. If you lower the scan width to 60° you guessed it, 0.6s.

 

Let's imagine the target is traveling at 300m/s.

If the target moves from 360m, at 18500m would it be obvious in the HUD target box ???

 

For the full 4 lines search pattern we can round up to 5s to scan the full volume. But no TWS here, no velocity vector, just contacts with closing velocity.

 

Take the values you would like to, at the end, it always comes to the conclusion that the shown behavor in my video from 0:39 to 0:49 just can't be true and is definitely false.

No matter if the box should be away 5 meters or 50 meters from the target, it just must not be on the target and smooth as soon as there is any kind of maneuvering.

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I have recently decided to load up the Mirage, just because its been quite some time. Almost immediately, I've noticed that some things have changed and maybe some new bugs. I just wanted to point out some problems I've had and maybe you guys could shed some light?

 

Sometimes I can select my 530's by selecting the button in the cockpit(single player mostly) and sometimes I cannot(multiplayer mostly). I have had to bind it to my HOTAS now.(No big deal, but why?)

 

Losing lock on target after launching 530(If you manage to get one off)

 

After losing said lock, you can no longer see anything on RADAR or RWR. Also, I am not able to select a target after losing lock.

 

The artificial horizon on the panel will no longer uncage. (This is not a big deal either, but why?)

 

Maybe these are pilot error or bugs or known bugs. Anybody else have similar issues? Let me know!

 

Thanks


Edited by TXGrunt

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Great work on filling out the bug tracker! Most of what I know is up there now :thumbup:

 

However, big item missing is this:

 

INS updates using radar or visual fixes do not use the location data presented by the radar designation pipper or ownship position respectively, rather they reset the error to 0. Same holds true for INS bombing mode.

 

I assume this is either unintentional or stop-gap behavior, but it's missing from the bug tracker so I can't be sure.

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