AN/APG-63v3 and JHMCS?

[GGTharos]

Higher PRF puts more energy on target per time-slice.

[TAW_Blaze]

But higher PRF also causes more ambiguity. You'll have a lot more signals that return later than one PRT, all of them if the target is further than PRT/2. Since we just lowered PRT by using higher PRF, we should have a lower Rmax, shouldn't we? Or did I go wrong somewhere?

[GGTharos]

You went wrong in thinking the radar design and pulse design doesn't already account for this :)

 

I'd have to hit the books to give you a technical explanation, because I no longer remember well. It's all a design thing though. I suggest you try to find the Radar Handbook or something like that and start reading.

[TAW_Blaze]

Thanks!

[Frostie]

My main thing is that in game right now, if you fly head on at each other, you will see each other at exactly the same distance. That would not be the case in real life.

Why not, the F-15s radar in the manual is listed as an APG-63, it doesn't state it as a (v)1, (v)2 or (v)3. It isn't an APG-70 as first announced back in LOMAC either.

The cockpit layout in FC3 for the F-15 has a pre APG-63(v)1 radar control panel, (the panel to the left of the throttle). There is no selector for INLV (interleave), HI, MED, RGH (similar to interleave) or VCTR. With this setup with an APG-63(v)1 the azimuth and ranges would be controlled with the HOTAS.

 

What control panel we have in FC3 however is the old APG-63 format - LRS, VS, SRS, PULSE and BCN, with the range and azimuth knobs featuring.

 

So considering it has MSIP (MPCD), the pre APG-63(v)1 + APG-70 radar control panel, and ED see fit to use its radar power similar to the N001 my conclusion is that the radar used by the F-15C in FC3 must be an APG-63PSP which is often attributed to being similar, sometimes less and sometimes more, in performance to the N001.

 

Much like the Su-27S, the cockpit tells the story, no SM upgrades for Su-27S cockpit, so no APG-63(v)3 for 20th century F-15 cockpit.

[opps]

New F-15C: DCS Flaming Cliffs manual says AN/APG-63(V)1 Radar.

But cokpit panel looks AN/APG-63 not (v)1

[GGTharos]

Why not, the F-15s radar in the manual is listed as an APG-63, it doesn't state it as a (v)1, (v)2 or (v)3. It isn't an APG-70 as first announced back in LOMAC either.

 

Because the original APG-63 had a 56nm range against a 1m^2 target. The 'medium RCS' target range is close to 100nm or more, I don't recall any more (I also don't know what medium RCS means in this context).

 

The cockpit layout in FC3 for the F-15 has a pre APG-63(v)1 radar control panel, (the panel to the left of the throttle). There is no selector for INLV (interleave), HI, MED, RGH (similar to interleave) or VCTR. With this setup with an APG-63(v)1 the azimuth and ranges would be controlled with the HOTAS.

 

APG-63 AZ is controlled with HOTAS by using AZ-bumping.

 

So considering it has MSIP (MPCD), the pre APG-63(v)1 + APG-70 radar control panel, and ED see fit to use its radar power similar to the N001 my conclusion is that the radar used by the F-15C in FC3 must be an APG-63PSP which is often attributed to being similar, sometimes less and sometimes more, in performance to the N001.

 

It's more, just not dramatically more like an AESA would be. It should be noticeable and significant though. For reasoning, look to better self-noise thanks to better electronics, more processing power, and antenna setup. Also, the Su-27 doesn't actually have more area than the F-15 radar antenna. It may in fact have less. This is because of the cassegrain setup. Resolution could be slightly better (it is governed by diameter), but power is governed by area. The Su-27 radar antenna has a huge hole in it. This is a large part (IMHO) of where some of the radar inferiority lies when it comes to this radar family.

 

Much like the Su-27S, the cockpit tells the story, no SM upgrades for Su-27S cockpit, so no APG-63(v)3 for 20th century F-15 cockpit.

 

Even a DCS F-15C wouldn't have a v2/3 IMHO. It's functionality is simply not known.

[Frostie]

Ok I've got this below which states both radars at over 100nm, could this be medium target. We know Russians have used 3-5m^2 as their standard gauge but this doesn't state Russian information. Both radars peak at about 5Kw If that is the case then you're probably talking about a 10% range advantage to the APG-63. But then there is another cloud of greyness in the form of each aircrafts RCS, if the Flankers RCS is slightly smaller than the Eagle then this would pull the detection ranges of each other closer together.

 

Other resources I've seen say 80-100km for N001 and 110km for APG-63. Obviously 56nm is 110km.

 

That being said what about Flanker upgrades, the export Su-27S the Su-27SK uses the N001E which has been labelled as 240 km. Surely the Russian would have upgraded their S to this spec or better.

 

 

 

 

Also, FC3 manual states an APG-63 while the DCS: Flaming Cliffs F-15C manual states an APG-63(v)1, is the new manual wrong?

Edited June 28, 2014 by Frostie

[GGTharos]

Ok I've got this below which states both radars at over 100nm, could this be medium target. We know Russians have used 3-5m^2 as their standard gauge but this doesn't state Russian information. Both radars peak at about 5Kw If that is the case then you're probably talking about a 10% range advantage to the APG-63. But then there is another cloud of greyness in the form of each aircrafts RCS, if the Flankers RCS is slightly smaller than the Eagle then this would pull the detection ranges of each other closer together.

 

Actually RCS has to be a lot smaller to get a significant difference. Think of it this way ... you need 1/16 of the RCS to halve detection range. Having half the RCS reduces range by 1/8th. Unless my math is borked in public, which happens.

 

Peak power is great and all, but it's not the only factor. Like I said, antenna construction and radar self-noise is a huge deal. You could build two radars of the same power but insanely varying performance based on gain/sensitivity driven by radar self-noise, as well as sidelobe noise etc. Even PD to CW is a huge change, though this is not a factor in this discussion.

 

Other resources I've seen say 80-100km for N001 and 110km for APG-63. Obviously 56nm is 110km.

56nm for a 1m^2 target. 'Medium sized target' is around 100nm, which actually jives well with 56nm for 1m^2 if you consider medium sized target to be sitting at the 10m^2 RCS mark IIRC - check the graph I posted above, along with the caveats I mentioned. In addition, it jives reasonably well with APG-59 performance from unclassified USAF documents. The 2-way radar formula takes into account a lot of the stuff I'm talking about here, but not clutter or atmosphere.

 

That being said what about Flanker upgrades, the export Su-27S the Su-27SK uses the N001E which has been labelled as 240 km. Surely the Russian would have upgraded their S to this spec or better.

I don't recall the N001E upgrade, but a flat plate antenna would increase range simply by virtue of increasing antenna area and eliminating some self-noise, so I wouldn't be terribly surprised. In that case, it would be a close match for the APG-63PSP.

 

Also, FC3 manual states an APG-63 while the DCS: Flaming Cliffs F-15C manual states an APG-63(v)1, is the new manual wrong?

I wouldn't worry about what the manual states right now. What we have in-game lacks functionality compared to pre-MSIP APG-63, excepting the existence of TWS. As you can imagine, it also lacks a lot of PSP functionality.

 

If you're only worried about radar range, I expect the v1 to be only slightly improved. The really huge improvement comes from the v2/3 which is a v1 with the AESA antenna and some other additional things. That antenna transmits a lot more power and is claimed to give the eagle 2-3 times the range of the original radar, AFAIK.

Edited June 28, 2014 by GGTharos

[GGTharos]

I don't know where Overscan gets his information, but if he's right, you have the radar with the upgraded processor from the 90's right now.

 

http://aerospace.boopidoo.com/philez/Su-15TM%20PICTURES%20&%20DOCS/Overscan%27s%20guide%20to%20Russian%20Military%20Avionics.htm

 

In 1985 NIIP were ordered to improve its performance. Attention and work had switched to the new N011 radar to equip the Su-27M, and problems with N001 persisted. According to NIIP, initial units had a MTBF of only 5 hours. Though the Su-27 entered service in 1986, its radar was not finally accepted into service until 1991. Eventually MTBF was brought up to 200 hours.

N001 has a 1.075m antenna diameter twist-cassegrain antenna. A pulse-doppler design operating in the 3-cm band utilising medium and high PRFs for optimum lookdown capability, the N001 has a search range of 80-100km against a 3 sq m RCS target in a headon engagement, 140km against a large bomber. It can track a 3 sq m target at 65km. In a pursuit engagement, search range for a 3 sq m target falls to just 40km. Azimuth limits are ±60° . It can also track ECM sources, and feed target data to the Su-27's IRST system.

The average power transmitted is 1kW (same as N019).

MTBF is 100 hours.

A radar datalink is used for updating inertially guided missiles such as the R-27.

[Frostie]

Yes I hear you with all that. Re. Kw, I actually meant to add that the smaller aperture on the N001 would make the difference.

[GGTharos]

Yep. Just my analysis. There ARE holes in it, but right now everything I have read and heard regarding the two radars is telling me that you got a bum deal in the flanker - comparatively. I'm not saying it's useless.

[USARStarkey]

All Su-27S have a standard N001 Radar. There have not been any upgrades to the Radar in the original Su-27S. All radar upgrades to the Su-27 have taken the form of new aircraft designations, IE: Su-30, or Su-27SM.

[GGTharos]

That isn't really true. No Su-27S uses the original N001 IMHO. There had been upgrades to it that made it work acceptably, from 85 to 91 or so, when the radar was accepted into service. That is the radar that is represented in the game, IIRC.

[USARStarkey]

That isn't really true. No Su-27S uses the original N001 IMHO. There had been upgrades to it that made it work acceptably, from 85 to 91 or so, when the radar was accepted into service. That is the radar that is represented in the game, IIRC.

 

That is what I mean, aside from reliability fixes, it is that same radar.

[Alfa]

Other resources I've seen say 80-100km for N001

 

Yes 80-100 km detection range agianst RCS=3m2 which would be something like an F-16, so likely a little better against an F-15.

 

That being said what about Flanker upgrades, the export Su-27S the Su-27SK uses the N001E which has been labelled as 240 km.

 

The Su-27SK is not an upgrade - its just an export designation for the original production version. Same goes for the radar. I believe the 240 km is the maximum displayable range calibrated for the HDD, which in turn may have more to do with GCI than onboard radar capabilites.

 

Surely the Russian would have upgraded their S to this spec or better.

 

Again the Su-27SK is just an export name for the Su-27S and the radar specs are the same. Only export versions of the Su-30 multirole variant(Su-30MK) have an upgraded version of the N001 radar(called N001VE), which in turn made it into the more recent Su-27SM.

 

During the late eighties Niip developed a slotted array radar called N011, which probably could have given a comtempory APG-63 radar a run for its money, but neither this nor the aircraft it was slated for(Su-27M aka Su-35) made it into production. So if you are looking for Flanker radars with significanty improved performance, you need to look at something like the furhter developed N011M "Bars" PESA(installed in the Indian Su-30MKI) or the latest iteration of this, the Irbis(installed in the Su-35S).

 

Btw in regards to the chart you posted - according to this the AN/APG-65(F-18 ) should have the same range("100 nm +") as the AN/APG-63.....so :)

Edited June 28, 2014 by Alfa

[Alfa]

That isn't really true. No Su-27S uses the original N001 IMHO. There had been upgrades to it that made it work acceptably, from 85 to 91 or so, when the radar was accepted into service. That is the radar that is represented in the game, IIRC.

 

Yes but then surely "the original N001" would be the improved one that was accepted into service :) .

 

Same way as you would refer to the original Su-27 as the "Flanker B" that went into production and not the rejected pre-production "Flanker A" :)

[GGTharos]

APG-65 would have less range when mounted on the F-18. I can change out the aperture and put in the correct size for the APG-65, you'd see a difference.

[GGTharos]

I internalize it that way to keep history straight in my head. Can't tell if it always works. But yes, I think the 1991 Su-27's were finally equipped with a more maintainable radar and the new processor which enabled it to reliably use the limited SNP mode AFAIK.

 

Yes but then surely "the original N001" would be the improved one that was accepted into service :) .

 

Same way as you would refer to the original Su-27 as the "Flanker B" that went into production and not the rejected pre-production "Flanker A" :)

[Alfa]

Yes I hear you with all that. Re. Kw, I actually meant to add that the smaller aperture on the N001 would make the difference.

 

But is the aperature smaller? - point taken about the hole in the dish, but the N001 antenna as such is larger(1075 mm diameter versus some 900 mm of the APG-63)

[Alfa]

I internalize it that way to keep history straight in my head. Can't tell if it always works. But yes, I think the 1991 Su-27's were finally equipped with a more maintainable radar and the new processor which enabled it to reliably use the limited SNP mode AFAIK.

 

Improved maintainability and likely also tweaked general performance, but AFAIK there was no change to the processor(at least not back then) - i.e. using the same Ts100 unit as the N019.

[GGTharos]

It may or may not be. I haven't done the math on it.

 

F-15 area: 2.63m^2

Su-27 area: 3.63m^2

 

This is without removing the hole or accounting for any occlusion.

[Alfa]

APG-65 would have less range when mounted on the F-18. I can change out the aperture and put in the correct size for the APG-65, you'd see a difference.

 

Eh yes GG, but the APG-65 was made for the F-18 and therefore has a *much* smaller antenna :)

[GGTharos]

I can only control the aperture, I don't know the other parameters. If you have a specific range vs. specific RCS, better yet, more than 1 point of reference, I can guess the other parameters semi-reliably.

 

APG-65 has also been mounted on the harrier with an even smaller antenna AFAIK, and possibly a larger one on the F-4.

[Alfa]

I can only control the aperture, I don't know the other parameters. If you have a specific range vs. specific RCS, better yet, more than 1 point of reference, I can guess the other parameters semi-reliably.

 

APG-65 has also been mounted on the harrier with an even smaller antenna AFAIK, and possibly a larger one on the F-4.

 

Of course GG - I am sure that an APG-65 could obtain similar range to a contempory APG-63 if modified with a wacking big antenna of the same size :) . But I was refering to the chart Frostie posted, where it simply said F-18A -> APG-65 radar and then stated the exact same "110 nm +" range for this as for the F-15C -> APG-63, which obviously isn't right.

 

I cannot find any good sources right now, but IIRC the antenna size for APG-65/F-18 is something along the lines of 25 inches(~ 630 mm) diameter and stated range performance is around 60nm against "fighter type target".