Fishbed & Viggen: radar raytracing?

[QuiGon]

The Viggen made me curious about radar technology in DCS. So I would like to have some questions clearified. For the moment:

- As far as I know the Viggen-radar in DCS will make use of raytracing for its ground mapping purpose, but not for detecting units. Is that correct?

- Does the MiG-21 radar uses raytracing?

I hope someone can shed some light on this :)

[Jumbik]

As far as I know the only other aircraft that will use raytracing (or waves simulation in general) for its radar modeling will be F-18C and probably A-7 from Razbam.

 

The current implementation of radar of all other aircrafts is based on different detection model.

 

But I'm basing this on all the information I have gathered from forums in past years, I have no proofs. :)

[Beamscanner]

I think the ray tracing technique is only being used for 'imaging' the ground at this point. Though it hasn't been detailed, I do believe LN is looking to improve the Jaybird radar display and effects.

 

Ray tracing would be very beneficial to improving the displayed artifacts of ground clutter.

 

Using ray tracing for A-A radar modes isnt necessary, because most fighter radars do not 'draw' images of airborne targets (though it is possible with ISAR waveforms).

 

I do believe that the RADAR/RWR/JAMMER/IFF systems need to be overhauled in this game though..

 

Repeater jammers should confuse or degrade RWRs (alter signal strength, direction, disrupt identification, and potentially create a false indication in the direction of the jammer.

 

RADARs should have unique sounds based on their waveforms (like IRL)

 

Modern Jammers should not jam signals identified as friendly

 

multi-path interference from close terrain should have an effect on the RWR (create errors in signal direction or lower the S/N ratio)

[Frederf]

Rasterized RP-22 would be amazing and above and beyond the call of duty. Analog radar imagery is really complex and interesting. It is a raw analog return with some additional effects for above/blow and IFF.

[amalahama]

This is an interesting question that won't be properly answered I guess, since everybody is holding cards very tight. I think that ED is developing a shader-based technology for the incoming F/A-18. Have a look at this:

 

http://www.isprs.org/proceedings/XXXVI/part7/PDF/101.pdf

 

https://www.researchgate.net/publication/224989618_Simulation_of_Imaging_Radar_Using_Graphics_Hardware_Acceleration

 

For LN it seems they are following a beefed-up, yet traditional, raytracing approach.

 

Regards!

Edited January 10, 2017 by amalahama

[QuiGon]

Thanks guys, it seems we really won't get much info on how this works under the hood :noexpression:

 

Thanks @amalahama for the two links. Interesting read! :thumbup:

[Cobra847]

This is an interesting question that won't be properly answered I guess, since everybody is holding cards very tight. I think that ED is developing a shader-based technology for the incoming F/A-18. Have a look at this:

 

http://www.isprs.org/proceedings/XXXVI/part7/PDF/101.pdf

 

https://www.researchgate.net/publication/224989618_Simulation_of_Imaging_Radar_Using_Graphics_Hardware_Acceleration

 

For LN it seems they are following a beefed-up, yet traditional, raytracing approach.

 

Regards!

 

The purely shader approach described in the whitepapers currently has some DCS limitations that did not make it feasible for us to use on the Viggen.

Edited January 10, 2017 by Cobra847

[amalahama]

The purely shader approach described in the whitepapers currently has some DCS limitations that did not make it feasible for us to use on the Viggen.

 

Fair enough, the shader-based method is mostly required for high resolution modes like DBS or SAR, your approach seems perfect for the radar type modeled :thumbup:

 

Regards

[Dirty Rotten Flieger]

What I have been asking for years is if the Mig21bis radar ground and cloud filters also lower the sensitivity for detecting aircraft?

 

I mean, if the filter didn't lower the detection range for aircraft then the engineers would have no reason to not have it always on...

 

But even if that is true we don't know what if modeled.

 

I guess I could just test the radar detection range against AI with and with pout he filters and see ...

[powerload]

Radar ray tracing is a very interesting idea. If it is true ray tracing against the actual surfaces of the aircraft model, it would provide some very interesting insights into a few things. There are now mods available adding F-22, F-35 and Su-57 to DCS. Make the radars work based on real ray tracing and... I'm sure you can see where I'm going with this...

[amalahama]

No I'm not

[powerload]

It means that if the model shape is accurate, with ray traced radar, the range at which a 5th generation fighter can be detected by radar will be realistically reduced.

[QuiGon]

It means that if the model shape is accurate, with ray traced radar, the range at which a 5th generation fighter can be detected by radar will be realistically reduced.

It's really not that simple or otherwise many countries would have stealth fighters in their inventory for a long time already. There are many other factors that play into that, like materials, fan blade and engine inlet designs and more...

DCS does already has RCS as a factor and thus stealth aircraft like the F-117 have a pretty low RCS in DCS.

[powerload]

I'm not disputing the importance of other factors, but it would still be very interesting to see just what difference the shape makes.

[amalahama]

The number of rays used in the AG radar modeling is wayyyyyyyy less than the number you would need for an effective computation - you would need a dedicated monster-GPU 2080-like just for getting enough rays to work out a significative RCS value in real time for just one 3D object, and yet the behaviour of microwaves are fundamentally different to visible waves, specially at low frequencies.

 

Bref: No, this technique is not useful for assessing RCS in a realistic way.