stealthflanker@moon_light
You don’t divide scan area with beamwidth. To get the scan time or “time frame” The methods is as follows :
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Derived from original equations from Stimson’s Introduction to Airborne Radar 2nd Edition
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Well admittedly clutters is not in the calculator yet. However if i decide to include it you will have to input at least flight altitude and grazing angle to determine clutter patch area. Plus we may have types of clutter, is it surface (Ground patch) or volume clutter (chaff, clouds or flocks of birds) For sea clutter we may have sea states.
stealthflanker@moon_light
They were operated as one radar. and see this :
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Beamwidth for Horizontal is Narrow because of number of elements. Linear array beamwidth is basically 2/N Thus for array of 24 elements it is 2/24=0.08 Radian or 4.7 degrees. Vertical beamwidth would basically be the element’s beamwidth which in this calculator assumed to be a patch with 114 degrees of vertical beamwidth. and no lens optimization. Beam positions need to be scanned is thereby low as the radar only scan in azimuth.
stealthflankerwow.. Looks amazing. AFAIK Low band system for EW often have MTI or STC applied that will reject low speed target (Thus birds, etc will not clutter the radar screen) The long range Radar may also usually have kinda long pulse which will eclipse target at short distance. Or perhaps the radar can identify the drone based on modulation caused by its rotors.
stealthflankerWell, been known for some time that Syrian MiG’s got R-77’s.
I would love tho to see these birds more in action defending their respective motherland.
stealthflankerJust want to share bit of attempt in calculating “potential” range of L-band wing leading edge radar.
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The assumption is Very Long dwell strategy of 0.3 seconds per beam positions making total scan time of 250 seconds. Shorter dwells of 0.1, 0.025 and 0.01 seconds are shorter ranged BUT faster update rates. The range are 54-120 km for the target. Such long dwell time is possible, however i wonder if the update rate would be acceptable.
The most difficult thing to predict is the change of target RCS. In this respect i rely on “Radar Cross Section 2nd Edition” Where it mention that object designed for low RCS in X-band will have 18dB more RCS in L-band (1250 MHz) Thus object having 0.001 sqm (-30 dB) RCS in X-band will have -12 dB or 0.06 sqm RCS in L-band.
stealthflankerThanks Paralay.
and @Haavarla
Well if only Sukhoi willing to answer ;w; You know i tried to correspond with some Mil company, the first was French manufacturer for Galix countermeasure. and later i tried to contact GRPZ Ryazan for information and possible picture of experimental Soyuz radar set (What supposedly N001 myech should be) But well… it seems i hold not enough credentials for asking ;w;
stealthflankerThis might be an old question but.. i kinda need reminder. What’s the empty weight of the latest Su-35’s ? Surely it’s not 16.8 metric ton figure for the early Su-27S’s but i wonder if 18-19 metric ton empty weight estimate realistic. and some 20-22 ton for the operating empty weight where the plane is fitted with with some weapons, equipment including pilot.
stealthflankerand now there is another concern related to our flanker deal. That our govt decided to attempt to re-negotiate the numbers of Flankers purchased. Originally it was 8, then 11 and now the number can go as high as 16. The problem is that it does not followed by increase in funding (The budget remains 1.14 B)
Now.. ppl are thinking.. with increase in numbers.. something must be reduced.. what is it ? Armaments deal ? or supports ?
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Regarding the supports. esp in point 1 in the documents i posted before. We clearly need a new jet engine test center as our test cell can only accommodate at best F-16 engine.
stealthflankerIt is update time and various other stuff.
What’s new :
-Antenna type added
https://sta.sh/024qp486qzs7
Allow range calculation for typical aircraft nose radar and linear array that might be embedded in your wing leading edge or vertical stabilizer.
-Scan time now determined by dwell time.
An advantages of AESA or general ESA radar is that the beam is controlled by computer and practically have no inertia, thus can be precisely controlled to achieve required dwell time/time on target.
Dwell time is basically the time where radar beam will “stay” in a sector. It’s a fraction of the total scan time (or time frame) or in fighter aircraft we know it as “scan cycle”
This is typical fighter aircraft radar scan scheduling. As you see typical scan for fighter aircraft radar is about 1-5 seconds. Too long may cause problem in terms of update rate and tracking verification. In conventional mechanically scanned radar, this determined by the mechanical ability of the radar (actuator, hydraulics etc), which not much can be done with it.
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In previous version user can input their scan time, which later the sheet will “allocate” it according to the scan area inputted by user. In this new version the scan time is now dependent on dwell time, which now made select-able in drop down menu by user.
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The value in the drop down menu is based on Typical dwell time for Long range early warning radar, target acquisition and typical fighter radar found in table 1.8. ch1 from Lynch’s “Introduction to RF Stealth”
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Another additional function is atmospheric effects in shape of attenuation by atmosphere, and rain.
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I would like to add snow, but there seems to be problem in interpolating available data, or more like it’s kinda hard to do so due to nature of atmospheric absorption. However for typical radar frequency it appears to be quite satisfactory. The model used is based on simplified K.Barton’s atmospheric attenuation model. There is more complete model by L.V Blake, but i decided not to use it for now to keep things simple.
Another improvements and additions are the antenna weighting algorithm. adding new algorithms which you can try and have fun with. If anyone asks why Taylor is the default it’s because Taylor weighting is the easiest to implement and quite robust.
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Below the weightings there are new tables detailing antenna parameters for Linear and planar array. They’re there to help calculating range in the next worksheet. The assumption for the linear array however is as follows :
1.Microstrip patch, with aggressive tapering in elevation beamwidth, original beamwidth was 114 degrees. However with proper lens treatment it can be reduced to the value you see in the table.
2.The spacing would still be half wavelength thus entire array length would be N*d where d is spacing in half wavelength. and beamwidth is Ka*(2/N) where N is number of elements and Ka is the weighting factor.
The planar array is your typical nose radar.
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Below the antenna table lies the dwell time selection table. This table lies the dwell time and will calculate the required scanning time based on the number of beam positions need to be scanned. In case you see changing the value of the scanning area increase the radar range, it’s because the sheet will adjust the value of the scanning time to the new sector. You can edit the dwell time value to your fitting. The scan time however is off limit.
Major change in Pre-calculated worksheet. Now most of it are automated Thus can’t be edited. You can still however edit the value on green columns
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System temperature now fully automated.
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Loss budget, some of it are still editable, and the radar range gate and receiver columns too.
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The fluctuation loss modeling. Now it’s fully modeled. The target is assumed to be Swerling case-2 target. Suitable model for tracking radar and what radar designer want target behave to. Swerling case 1 could also be applied. However this model is more suitable for search radar, esp rotating search radar.
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The new worksheet. The atmospheric effect, the most likely source of problem. This worksheet contain the “atmospheric model” and radar receiver noise figure “model” Based on excel trendline interpolation. The data is fortunately fits well so, the calculator is “work” However in the future i will implement better module.
As always feedback are appreciated.
Download Link for updated version :
https://www.mediafire.com/file/7wrkyslc1p4d36r/AESACalcTrial.xlsx
stealthflankerThe initiative now lies in our side. Especially in that first point.
Problem is that the NTP our Gas turbine maintenance company, is privately owned. There is a concern that it will have difficulty in actually find funds or state funds to upgrade the facility. Testing and maintenance of new engine requires tooling which need to be purchased and of course manpower. Plus there will be concern about profitability given the small fleet we operates. If UAE purchased Su-35, we might got the cake for their engine maintenance as when Iran sent their 727 and 737 engines to be maintained here (yes they did).
Another weird in the paper is the “PT APP”.. which well owned by Sinar mas Group. This according to google search is a pulp and paper company, which well if it really need to produce hose etc it would have to invest a whole new industrial base for it.
The worst of all is that those points could be just a “placeholder” just to fullfill the constitutional conditions (That everything we bought abroad need to have some percentages of local content and ToT)
However this is not the first time that mess occurred. our BMP-3 “ToT” program suffers similar story… and no not the fault in Russian side.
stealthflanker@TR1
This is what we got from 85-90 mil price of Su-35.
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stealthflankerCan i speculate a bit on implementation 😀 ?
What do you guys think on my guess on architecture for Pantsyr SM’s new engagement radar.
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It’s too generic But.. it’s quite clear i think. So i speculated that the design is Hybrid multi-band AESA-PESA design with TRM and transmitter for the second band located at back. The front face of the antenna is the PESA part, containing the radiating elements for the AESA and PESA’s phase shfiters and radiating element. Behind it there is a reflector for reflecting wave originating from the feed to “feed” the collecting PESA phase shifters antenna for beamsteering. Another part is AESA waveguide or strip to carry power from AESA trm to radiating element. They seem long in the image, BUT Pantsyr works in milimmetric wave band, thus the phase shifters is probably smaller than your little finger.
The array would be full face with number of elements about 8595 (assuming 1.5 cm wavelength) or higher. Given 2 band operations, only half at least would be available for the each band. Not a problem tho as one need to do is to arrange the elements and optimize scanning angle. Tor system did that and managed to achieve 42 dB of gain with only 500 phase shifters modules, spacing however is 3 wavelength and it put hard limit on electronic scan, to 7 degrees. I expect the SM will do better due to more elements being available.
Half of the modules that are not used will act as taper to optimize sidelobe.
The rationale of such design is basically to minimize cost as full fledged dual band AESA in the same working frequency as Pantsyr will probably cost more than the whole system itself. The 0.9-1 m diameter AESA. assuming full FOV will require at least 8595 modules. Price of modules in Ku band is still quite high due to required precision manufacture to make them.
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Higher frequency may inflict even higher price. 8595 modules, assuming U$ 750 in 2017 will make the total price of radar at least U$ 6,446,250 or yeah six million dollar Should true dual band AESA design sought, sharing the same radiator, the cost would easily double unless the second band use less modules. The Russian system with arrangement i speculated, might cost less, or at least half of the “full fledged” AESA.
It’s true that forward feed spaced array will suffer not only from phase shifter loss but also non optimum sidelobe performance due to blocking. The AESA part however will only suffer from the blocking by the feed. If the intention for the second PESA band is to provide “emergency” band in jamming condition OR missile guidance/capture i think the penalty could be minimum as larger beamwidth is desirable in capturing missile during flight (Thus reason of why missile capture antenna on command guidance systems are small, they’re wide beamwidth). The feed can also be easily made to have circular polarization, a desirable feature for missile guidance command link as it less affected by missile attitude, the main AESA array can be optimized to have horizontal or vertical polarization to engage airborne target.
The prime band could be made in lower frequency (X-band) thus achieveing even lesser cost BUT wider beamwidth generated by X-band may make the radar runs into problem of glint while engaging target at low elevation angle (horizon) due to multipath generated when the mainlobe or sidelobe hit the ground.
stealthflankerI see. hmm the existence of feed at front is kinda hair raising tho. kinda reminds me of the Pero and Klinok.
My guess it’s a feed for 2nd frequency band, reserved for countermeasure.
stealthflanker@Scar is that article said that the new antenna shown in the article is an AESA ?
stealthflankerLooking at the TV reports on Kalibr launch..hmm so it does use cold launch method. However instead of using compressed gas like S-300 or other Russian SAM’s It use explosive charge to generate the high pressure gas which expel the missile.
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