Radar "readjustment"

[TLTeo]

  

Yeah I haven't been mentioning the FC3 jets because those are really, really old and really, really simple (and really, really wrong).

 

1 minute ago, GGTharos said:

here the 68v9 and 73 would be 'it'

Yeah, especially the 73 since it's part of a flagship module and it recently was updated. That comparison shows that both the Viper and Jeff need some double checking at the very least

[Harlikwin]

15 minutes ago, GGTharos said:

The F-15's radar is 20-30nm short of what it should be, but that's the F-15s problem.   The KLJ-7 is best compared and understood vs radars that are similar, and here the 68v9 and 73 would be 'it'.

 

Yeah, thats fair, the numbers I have put it more close to 20 than 30, but thats up to ED to fix in FC3 which has its own pile of problems with radar modeling. 

11 minutes ago, TLTeo said:

  

Yeah I haven't been mentioning the FC3 jets because those are really, really old and really, really simple (and really, really wrong).

 

Yeah, especially the 73 since it's part of a flagship module and it recently was updated. That comparison shows that both the Viper and Jeff need some double checking at the very least

 

That was simply my point. In 2.5.6 they were "relatively" speaking roughly reasonable when rank ordered. Now that the hornet is updated I'd like to see the Viper and Jeff "reevaluated" the viper for sure needs a fix, and I'm guessing the Jeff might too. 

TBH I really do wish the ED would model some of the downsides to these various modes as well. HPRF is gonna give you range ambiguity and its easy to notch, which isn't great for say guiding missiles, but AFAIK thats not modeled at all in DCS. So everyone uses TWS and HPRF pretty much all the time... 

Edited May 4, 2021 by Harlikwin

[dundun92]

15 minutes ago, Harlikwin said:

easy to notch

HPRF AFAIK is easier to notch in DCS. But you are right, the range ambiguity is missing, its really just one of many missing things from EDs radar modeling.

[Harlikwin]

9 minutes ago, dundun92 said:

HPRF AFAIK is easier to notch in DCS. But you are right, the range ambiguity is missing, its really just one of many missing things from EDs radar modeling.

 

Maybe, the AWG-9 is the main one I noticed is very notchable. I haven't noticed HPRF vs MPRF mattering much in other airframes like the mirage, jeff, or F15/flankers (don't fly those much). 

If I had a wishlist for fixing "RADAR" in DCS it would be:

Make modes matter i.e. HPRF vs MPRF (and LPRF if anything uses it)
Make there some tangible difference in terms of TWS and its errors versus other modes i.e. STT (should give you better guide and be harder to break a lock).

Make RCS and target aspect and "loadouts" matter. This can be calculated offline for airframes, and put in a chart in some basic fashion like using POFACETS in Matlab.

 

http://ausairpower.net/PLA-VLO/Chengdu-J-20d-0300GHz-Rs0000-IncPol-TM-Pol-Theta--E=0000-A=0000-.png (this was calculated in matlab in 2011) You can do this for the main airframes in DCS without a huge effort, its plug/n/chug for some interns. You already have the 3d models, and you can add stores to them. 

 

1.16 compliant open source from here: http://ausairpower.net/APA-2011-03.html

Edited May 4, 2021 by Harlikwin

[dundun92]

43 minutes ago, GGTharos said:

Edit:  Here's a source for the 68v9 which unfortunately offers no numbers.   This radar and the KLJ-7 seem to be similar in size, power and purpose.    https://science-naturalphenomena.blogspot.com/2010/12/anapg-68.html

Extending the range of the v9 required a completely new transmitter.

On the topic of the V9, the paper "On the use of AESA (Active Electronically Scanned Array) Radar and IRST (InfraRed Search&Track) System to Detect and Track Low Observable Threats" lists the V9 range as 38nm vs 1m^2, or 57nm vs 5m^2.

Its supposedly based on "open sources", though the paper doesnt list said sources. It also doesnt specify RWS/VS, however AFAIK the V9 now uses just a generic ERS mode, im not sure it has a specific VS though I could be wrong.

Edited May 4, 2021 by dundun92

[Harlikwin]

Just now, dundun92 said:

On the topic of the V9, the paper "On the use of AESA (Active Electronically Scanned Array) Radar and IRST (InfraRed Search&Track) System to Detect and Track Low Observable Threats" lists the V9 range as 38nm vs 1m^2, or 57nm vs 5m^2.

Its supposedly based on "open sources", though the paper doesnt list said sources

 

Yup, and the V5 is gonna be less than that by some double digit percent margin ~20% at a guess. 

[dundun92]

Just now, Harlikwin said:

 

Yup, and the V5 is gonna be less than that by some double digit percent margin ~20% at a guess. 

IIRC the V9 was supposed to be 33% better than the V5 (well actually than V7 but the V7 im pretty sure has the same RWS detection range) according to the brochure and other sources. Whether this is 33% better than the V5s VS or RWS IDK, id assume RWS as its the most directly comparable (both all-aspect detection modes)

[GGTharos]

So what is the conclusion?  Are we ok with the KLJ-7 being here it is?

[Skysurfer]

15 minutes ago, GGTharos said:

So what is the conclusion?  Are we ok with the KLJ-7 being here it is?

 

I mean given there is no additional data, I guess. Unless someone gets the official radar parameters and punches them into the basic radar range equation for x-check.

[Schmidtfire]

This article might not be correct. But according to one PAF pilot, JF-17 was getting a radar lock-on Su-30MKI at more than 100km-ranges.
So it seems like it would match the KLJ-7 documentation.

https://eurasiantimes.com/powerful-jets-with-one-weakness-pakistani-jf-17-pilot-recalls-clash-with-indian-su-30mkis/

The F-16's launched AIM-120 at roughly 100km (54nm). This proved to be advantageous because the max range of R-77 is less than 80km.

If this article is correct it looks like both F-16/JF-17 radars should have no issues with detection and lock-on at 100km. 

Edited May 4, 2021 by Schmidtfire

[GGTharos]

I believe the detection range because those aircraft have a 15-20sqm RCS, not the 5.5 they're set to in game.   The 120 shot range is like ... what.   That makes no sense at all.

[TLTeo]

Yeah we can't just get those numbers (even without factoring in all the propaganda that went in that particular incident) and pretend we can just compare them to DCS numbers.

41 minutes ago, GGTharos said:

So what is the conclusion?  Are we ok with the KLJ-7 being here it is?

My gut feeling is it probably should be toned down a bit to ~APG 73 levels-ish but obviously when if the only data available are a fancy brochure and politically-charged statements, it's hard to have a well motivated opinion.

[Schmidtfire]

7 minutes ago, GGTharos said:

I believe the detection range because those aircraft have a 15-20sqm RCS, not the 5.5 they're set to in game.   The 120 shot range is like ... what.   That makes no sense at all.

Yeah, I was a bit baffled by the shot range. The advantage of having a longer stick. Maybe trying to force them defensive early? Very low pk, but they did break and run. Also, several Su-30MKI and F-16 casualties would have been a very serious incident... 

"First look, first shot"

Edited May 4, 2021 by Schmidtfire

[GGTharos]

I think they're just quoting brochure ranges and nothing more.

[Schmidtfire]

I guess it's difficult going by anything but the brochure. Everything else is just guesswork if we cannot get other data somehow.
One interesting aspect. Has Deka stated if it is a KLJ-7V1 or V2? Just asking because there are some Block II features on the DCS: JF-17 

KLJ-7V1 is Pulse Doppler, mechanically steered Array Radar & is equiped on first batch of 50 JF-17 Block 1. Its a Multimode Fire Control Radar (FCR) which operates at X-Band i.e (7GHz-11GHz). In A-A look up mode it have range of ~105KM for 5m^2 target & ~85KM for 3m^2 & 150KM for Sea-Surface threats.

KLJ-7V2 is a modified version of KLJ-7 V1 having more power & hence providing more range. It is equiped on 60 JF-17 Block 2s. KLJ-7V2 can detect 40 targets, can track 12 & engange 2 simultaneously & provides A-A mode for 3m^2 targets, ~150KM for 5m^2 & 200KM for sea targets.

 

[Harlikwin]

1 hour ago, GGTharos said:

So what is the conclusion?  Are we ok with the KLJ-7 being here it is?

 

Well currently the Viper range vs 5.5m^2 target is 77nmi. Which probably should be about ~40 IRL for a 5m target or less. 

For reference The current RWS range for the F18 is now 48hi/26med prf (matching a chart I have), and thats for a radar that should be a good bit better than APG-68 both due to size and PRF. And those ranges are equal for the M2k RDI radar in game as well. 

The jeff in game is: 66/57/53 (hi/ilv/med) and 80 in VS... And the F15 is currently 65nmi in hi prf, which probably should be closer to 80... 

 

My 2 cents on this: No way is the KJL-7 the equal to an APG-63, and probably not the APG-73 just due to simple fact of antenna size and the fact you can stuff way more power and cooling into those airframes. Doubling your TX output is at best gonna give you 3dbi on the way OUT. I'm sure everyone knows that doubling your antenna gain (simpler) is gonna give you 3dbi on the way out AND on the way back in... Now we don't know the precise gain levels of the antennas, but it scales with size/area at the frequencies we are talking about. And the KJL-7 has the smallest antenna of any of the radars mentioned for the simple reason the jeff has the smallest nose. 

 

So my 2 cents again, it should probably be somewhere between the current APG-73 and APG68v5 due to the fact it has hiprf and lets say its more "modern" so has a better noise floor and maybe a bit better/cooling and power. But even doubling your power isn't by any means doubling your range, it means that you need more power and more cooling, both of which take "volume" and are scarce resources on all planes. 

 

14 hours ago, TLTeo said:

The brochure doesn't specify either mode (VS generally should have longer range than RWS) nor closure though, so it makes no sense to compare a claim on a brochure with actual DCS numbers. You could bring the VS range down to ~65nm where RWS is now, bring RWS range down to e.g. the RDI range of ~50nm in high PRF and ~35nm in medium PRF, and you could still say "hey this works exactly like the brochure says!"

 

It's one of two things - either the KLJ-7  is currently over performing for whatever reason (and the Viper is spot on, and the Hornet was spot on but was made to under perform with 2.7), or every other radar in the game is grossly under performing.

 

 

Yeah, and TBH its the relative performance that is the thing that really matters. And we can make a few informed guesses on that. IMO, the hornet/Viper/jeff were all overperforming in 2.5.6, but most people were kinda ok with that since they didn't know. Now all of a sudden the hornet radar "fits" DCS and reality a bit better, and now the Viper and Jeff seem to be the outliers. 

Edited May 4, 2021 by Harlikwin

[TLTeo]

29 minutes ago, Schmidtfire said:

I guess it's difficult going by anything but the brochure. Everything else is just guesswork if we cannot get other data somehow.
One interesting aspect. Has Deka stated if it is a KLJ-7V1 or V2? Just asking because there are some Block II features on the DCS: JF-17 

KLJ-7V1 is Pulse Doppler, mechanically steered Array Radar & is equiped on first batch of 50 JF-17 Block 1. Its a Multimode Fire Control Radar (FCR) which operates at X-Band i.e (7GHz-11GHz). In A-A look up mode it have range of ~105KM for 5m^2 target & ~85KM for 3m^2 & 150KM for Sea-Surface threats.

KLJ-7V2 is a modified version of KLJ-7 V1 having more power & hence providing more range. It is equiped on 60 JF-17 Block 2s. KLJ-7V2 can detect 40 targets, can track 12 & engange 2 simultaneously & provides A-A mode for 3m^2 targets, ~150KM for 5m^2 & 200KM for sea targets.

 

The Jeff in game can track 10 targets in TWS rather than 12 iirc, so my guess is it's supposed to be a block 1 radar. Iirc the "block 2 features" mostly means the aar capability. Assuming those numbers are correct, then yeah, the range performance is more in the block 2 range.

[Harlikwin]

Just now, TLTeo said:

The Jeff in game can track 10 targets in TWS rather than 12 iirc, so my guess is it's supposed to be a block 1 radar. Iirc the "block 2 features" mostly means the aar capability. Assuming those numbers are correct, then yeah, the range performance is more in the block 2 range.

 

Yeah, I'm really curious how they stuffed that much more power in the airframe and radar to basically double the detection range unless its not actually "power" and maybe a serious antenna tech optimization. I mean going from 85->150 is a big change. 

57 minutes ago, GGTharos said:

I believe the detection range because those aircraft have a 15-20sqm RCS, not the 5.5 they're set to in game.   The 120 shot range is like ... what.   That makes no sense at all.

 

DCS RCS needs a serious rework in general. Like I said earlier, ED could do it with minimal resources IF they wanted to, it would be consistent and at least ballpark accurate. But actually motivating them to do it... 

Edited May 4, 2021 by Harlikwin

[Blinky.ben]

7 hours ago, TLTeo said:

Again, as Harlikwin said, the main parameter that determines that is the antenna size. Fancy signal processing can only give you so much - for example, going from the oldschool APG 68v9 to its AESA equivalent (the APG 83, which is far, far more advanced than any mechanically scanned radar except perhaps CAPTOR on Typhoon) only increases detection range by ~15% - ish to about 50nm (source: https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf ). Obviously with better signal processing and/or AESA/PESA you get other benefits beyond sheer range, but that's not captured in DCS anyway.

 

It is just not possible for the KLJ-7 to be some ~70% better than Western radars which have similar (or larger, in the case of the Hornet) antennae. It's not how the laws of physics work.

 

So I wonder how the 20inch antenna We used to have got us 256nm maximum detection ranges or about 48nm detection ranges for 2m2 surface vessel, before we upgraded the radar system that had a 22inch antenna with almost half the detection ranges?

 

after 18 years with working with military radars I know the answer. I’m just trying to prove Wikipedia in terms of radar theory although not completely Wrong but can be extremely miss leading

 

i ask questions about radars on these forums cause of trying to understand DCSisms and also I don’t want to dig through charts for radar theory for each different radar. I already work 100 fourth nights that just feels like more work.

7 hours ago, TLTeo said:

Again, as Harlikwin said, the main parameter that determines that is the antenna size. Fancy signal processing can only give you so much - for example, going from the oldschool APG 68v9 to its AESA equivalent (the APG 83, which is far, far more advanced than any mechanically scanned radar except perhaps CAPTOR on Typhoon) only increases detection range by ~15% - ish to about 50nm (source: https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf ). Obviously with better signal processing and/or AESA/PESA you get other benefits beyond sheer range, but that's not captured in DCS anyway.

 

It is just not possible for the KLJ-7 to be some ~70% better than Western radars which have similar (or larger, in the case of the Hornet) antennae. It's not how the laws of physics work.

 

So I wonder how the 20inch antenna We used to have got us 256nm maximum detection ranges or about 48nm detection ranges for 2m2 surface vessel, before we upgraded the radar system that had a 22inch antenna with almost half the detection ranges?

 

after 18 years with working with military radars I know the answer. I’m just trying to prove Wikipedia in terms of radar theory although not completely Wrong but can be extremely miss leading

 

i ask questions about radars on these forums cause of trying to understand DCSisms and also I don’t want to dig through charts for radar theory for each different radar. I already work 100 fourth nights that just feels like more work.

[Harlikwin]

16 minutes ago, Blinky.ben said:

So I wonder how the 20inch antenna We used to have got us 256nm maximum detection ranges or about 48nm detection ranges for 2m2 surface vessel, before we upgraded the radar system that had a 22inch antenna with almost half the detection ranges?

 

after 18 years with working with military radars I know the answer. I’m just trying to prove Wikipedia in terms of radar theory although not completely Wrong but can be extremely miss leading

 

i ask questions about radars on these forums cause of trying to understand DCSisms and also I don’t want to dig through charts for radar theory for each different radar. I already work 100 fourth nights that just feels like more work.

 

 

So let me get your argument as it applies here. Correct me if I'm wrong cuz it sounds like chest thumping nonsense to me, and I want to give you the benefit of the doubt. 

 

So you went from a 20" antenna of an undefined type, with undefined gain characteristics that could detect a 2m^2 surface target 256nm , to a larger undefined 22" antenna (so 10% larger) with undefined gain characteristics in both cases and undefined power and frequency for either system that could detect (the same?) 2m^2 surface target at 48nm? Did the operating freq change? Did the power change? Otherwise a fun processing technique for ground targets is synthetic aperture  which helps a lot if your "target" isn't moving cuz you can make your antenna "bigger" but its fairly useless  in the A/A case. And SAR is modeled in the various DCS ground modes. So I'm not really clear on your point? Is it to try to compare ground mapping synthetic aperture to air to air modes? I mean literally all I got from your post was that you have 18 years of "experience" with "radar", is it cleaning them, polishing them, looking at them from 10m away? Because otherwise your post made exactly zero sense.

 

Edited May 4, 2021 by Harlikwin

[Blinky.ben]

5 minutes ago, Harlikwin said:

 

So let me get your argument as it applies here. Correct me if I'm wrong cuz it sounds like chest thumping nonsense to me, and I want to give you the benefit of the doubt. 

 

So you went from a 20" antenna of an undefined type, with undefined gain characteristics that could detect a 2m^2 surface target 256nm , to a larger undefined 22" antenna (so 10% larger) with undefined gain characteristics in both cases and undefined power and frequency for either system that could detect (the same?) 2m^2 surface target at 48nm? Did the operating freq change? Did the power change? Otherwise a fun processing technique for ground targets is synthetic aperture  which helps a lot if your "target" isn't moving cuz you can make your antenna "bigger" but its fairly useless  in the A/A case. And SAR is modeled in the various DCS ground modes. So I'm not really clear on your point? Is it to try to compare ground mapping synthetic aperture to air to air modes? I mean literally all I got from your post was that you have 18 years of "experience" with "radar", is it cleaning them, polishing them, looking at them from 10m away? Because otherwise your post made exactly zero sense.

 

 

I wasn’t finished with with working on that post but didn’t realise it posted. But no I gave the detection ranges for one radar and stated that the ranges we got with the new radars are less.

exactly what your have stated through your questions my point was that antenna size has a influence but it is not the main cause for maximum antenna ranges hence why all the important factors were left out.

[Harlikwin]

18 minutes ago, Blinky.ben said:

I wasn’t finished with with working on that post but didn’t realise it posted. But no I gave the detection ranges for one radar and stated that the ranges we got with the new radars are less.

exactly what your have stated through your questions my point was that antenna size has a influence but it is not the main cause for maximum antenna ranges hence why all the important factors were left out.

 

It is still the major determinant AFAIK. Power doesn't scale, literally to double the effect of your power you have to put in 4-8x as much, instead of merely doubling your antenna gain, because antennas work both ways, and power only works one way, a 3dbi antenna is the equal of going from 100MW to 400MW of power assuming 100% effiencicy which its not. Processing doesn't scale anywhere near as much, you might lower your noise floor a bit here and there but its not huge. That being said, if its SAR it can literally be "miles" long as in the case of scientific satellites. A bigger antenna ALWAYS works both ways and ALWAYS works better than "MORE POWAR", most of the antennas we are talking about have 30db or more gain, and are maybe 50-70% power efficient. So, going from a 30dbi to 33 dbi antenna (thats 3db out, and 3db back in so 6db total) is gonna net you the same as going from 100MW as 800MW assuming a 50% energy loss. I mean if you are super clever it might be like 70% efficient in terms of power use. Processing or low noise components might net you a db here or there on the receive side. But something like an APG68 is already pretty well processed. Frequency vs antenna size does scale. So the same size antenna at 8GHz will have more gain if its running at 12 GHZ but its not that huge, again you might get 3db there. Plus the design of any antenna has to consider sidelobe noise.

https://www.researchgate.net/publication/264111387_Design_of_a_Planar_Slotted_Waveguide_Array_Antenna_for_X-band_Radar_Applications

 

 

SO.... TLDR.... IF we are oversimplifying the shit out of it like we are in DCS THE BIGGER ANTENNA WINS...

 

Or maybe militaries for decades have been total idiots building OCA fighters with Huge ass Radar antennas (Ala, F14, F15, Mig31, SU-27) IDK, maybe Ben can tell us why they built those?

 

 

Edited May 4, 2021 by Harlikwin

[uboats]

Thanks for your interests and concern about the radar performance

in our sim, we actually implemented KLJ7v1.

the radar screen max range 80nm doesn't mean it can detect contact as far as 80nm. Any contact beyond 40nm needs to scale the screen to 80nm

AFAIK, KLJ7v1 is almost the newest radar which was developed in mid-late 2000s. the perf of radar not only relies on the power, but also the post process (signal process). newer radar normally has better post process (in algorithm as well as circuit design), that with a good signal filter, even some weaker contact echo can be identified.

compared to all public info (from CETC), as well as what we know, current radar perf is reasonable

if you have other questions, you can ask @L0op8ack

Edited May 5, 2021 by uboats