Question about the radar picture

[QuiGon]

I'm in the process of reading through the DCS F-14 manual and I'm currently at the chapter about the WCS. Reading through all the knobs and switches that the RIO has at his disposal to adjust the radar picture on the DDD makes me think about how a skillful RIO can take advantage of the raw and analogue nature of the DDD to get cues that a digital radar display or a less skillful RIO won't provide. Well, in theory at least, because it can be quite difficult to accuratly simulate such analogue systems with their raw data output in a video game. On a typical digital radar display (which is what pretty much all the playable radar equipped aircraft in DCS have so far with the exception of the Viggen) it can just show a contact on the display according to where the detected aircraft is in the world (provided it is within radar parameters of course). Now with an analogue display like the DDD, which shows raw radar returns, it gets difficult, because it needs to visualize all the electromagnetic rays that it detects on its operating frequency.

I'm not entirely sure how DCS handles radar simulation internally (e.g. if and how it makes use of raycasting to trace radar rays), so I wonder how the DDD will show radar returns especiall if they come from different surfaces or objects other than aircraft?

 

As this all was rather theoretic I will provide a specific example: The RIO can use the PD THRLD control knob (see here under "Radar and DDD Control Knobs") to adjust the signal strength threshold of a pulse doppler radar return to be displayed in the TID (which is a digital radar display unlike the DDD). That means if we encounter a small aircraft with a rather small radar return (e.g. a F-5 or a MiG-21), its radar reflections might be visible on the DDD while it will not show up on the TID as its radar returns are below the threshold. The RIO could then change that by lowering the PD THRLD, so that the signal strength of the radar returns is above the threshold level and the contact appears on the TID. At least that is how I understand it.

Now, what happens if we just set the PD THRLD control knob to the lowest possible setting? That would cause contacts to appear on the TID very early, as their radar reflections would be above the threshold even if they are still far away and provide only weak returns. I guess the disadvantage in real life of doing so would be, that a lot of false contacts would appear on the TID, as radar rays will be reflected back to the Tomcat by various other things apart from aircraft (e.g. clouds, buildings, terrain, ...).

Will this be the case in DCS as well or will the TID only display actual aircraft contacts, so that we can keep the PD THRLD at it's lowest setting without having to worry about false contacts or other disadvantages?

 

 

Edit: I forgot about the dev update about the AWG-9 back in 2017: https://forums.eagle.ru/showthread.php?t=196159

It explains the first part of my question, how the DDD will display radar returns from other surfaces or objects than aircraft:

 

But the 2nd part of the question still remains, if and how those returns will be displayed on the TID when the PD THRLD is set to its minimum?

Edited February 28, 2019 by QuiGon

[TLTeo]

In principle yes, if you lower your threshold enough you should eventually get ground clutter/returns in Pulse Doppler mode (as you would expect in Pulse mode), so I wouldn't be surprised if that happened in the game. I'm not sure about clouds though, it's hard to say whether they have any returns modelled in DCS or not.

[corvinus]

In principle yes, if you lower your threshold enough you should eventually get ground clutter/returns in Pulse Doppler mode (as you would expect in Pulse mode), so I wouldn't be surprised if that happened in the game. I'm not sure about clouds though, it's hard to say whether they have any returns modelled in DCS or not.

 

 

And don't forget internal system noise, if you lower the threshold, all you will see is noise ...

[QuiGon]

In principle yes, if you lower your threshold enough you should eventually get ground clutter/returns in Pulse Doppler mode (as you would expect in Pulse mode), so I wouldn't be surprised if that happened in the game.

And don't forget internal system noise, if you lower the threshold, all you will see is noise ...

What display are you guys talking about? The DDD? Then yes, it would be cluttered with contacts, but what about the TID? The threshold knob defines at what signal strength a return gets displayed as a contact on the TID as well, meaning that the TID would get cluttered with contacts as well, even if there are no aircraft, because the radar returns are just noise (from clouds, buildings, ground, internal).

Now my question is: Does Heatblurs TID simulation allow for such false contacts? Because if that is not the case, then there would be no reason to not lower the threshold all the way.

 

 

I'm not sure about clouds though, it's hard to say whether they have any returns modelled in DCS or not.

The MiG-21 radar shows cloud returns in DCS.

Edited February 28, 2019 by QuiGon

[corvinus]

What display are you guys talking about? The DDD? Then yes, it would be cluttered with contacts, but what about the TID? The threshold knob defines at what signal strength a return gets displayed as a contact on the TID as well, meaning that the TID would get cluttered with contacts as well, even if there are no aircraft, because the radar returns are just noise (from clouds, buildings, ground, internal).

 

I thought that was what I was saying ...

[TLTeo]

^same. Also,

 

 

The MiG-21 radar shows cloud returns in DCS.

 

 

I don't have the Mig21 so I didn't know, that's very cool! I haven't noticed any in the F5 or Viggen which is why I was unsure.

[QuiGon]

I thought that was what I was saying ...

But I guess you were talking about how it is IRL? I would like to know if it will be like that in the game as well.

[Naquaii]

Unfortunately PD THRLD is not something we're modelling at release.

The current model assumes that that control is left in the auto detent (NORM) allowing the computer to control that.

 

This is something we'd eventually like to model but haven't prioritized for EA release.

 

Like you guys have mentioned the effect, if lowered, would be more targets but also more false echoes which would translate to spurious and erroneous contacts on the TID in RWS and TWS.

 

Especially TWS is vulnerable to this because of the 18/24 target limit which can quickly fill up with false targets.

 

I appreciate you guys asking questions like this and the radar model will for sure get more detailed as we continue along in EA! :-)

[QuiGon]

Thanks a lot for the clarifying answer Naquaii! :thumbup:

 

I assumed the PD THRLD is implemented, because it was well described in the manual without having the small note below it that says it isn't implemented. I can imagine how difficult it is to simulate such analogue systems in DCS, so I was a bit suprised to not see that note there. I hope it will be possible to implement that feature, as it would make the RIOs job even more interesting and challenging! :)

Edited March 1, 2019 by QuiGon