Russian PESA and AESA Radars

Tell me Garry, what is the difference between PESA and AESA, which is better? Sorry for the question but trying to learn that stuff, am really interested in it.

SerbNationalist wrote:Tell me Garry, what is the difference between PESA and AESA, which is better? Sorry for the question but trying to learn that stuff, am really interested in it.

Related to PESA or AESA , the primary differences between them is their power source , PESA RADAR uses Single transmitter to transmit their beam , their Antenna elements contains no "Active" elements, only Phase Shifters for their electronic Scanning .

Example is Irbis-E RADAR which uses 2 Travelling Wave Tube to form its transmitter system, it's antenna contains nothing but a beam steering controller and phase shifters .

as for AESA every antenna elements mounted on it have their own transmitter in shape of MMIC (Monolithic Microwave Integrated Circuit) along with power amplifier , thus every element can transmit power by itself , and those devices are mounted in the Antenna (PESA transmitter is NOT in the Antenna but in separate module/LRU) .

as for AESA Vs PESA comparison , the primary advantages held by AESA over PESA is in the Reliability of the transmitter, PESA transmitter (Travelling Wave Tube, Klystrons, Magnetrons ) are usually "short lived" due to the fact that they often handle very high amount of Microwave power in often very confined or small space, like say fighter RADAR's , their MTBF (mean Time Between Failure) is somewhere between 200-300 Hrs , and can be as low as 5 hours (early Su-27's N001 Myech RADAR's) once the transmitter fail , the entire RADAR will cease to function .

AESA RADAR in other hand , since MMIC modules handle lower power (5 watts till some 100 watts) their reliability is higher , APG-79 MMIC T/R Modules may last with MTBF up to some 20.000 Hours , another advantage is since each modules have its own transmitter, failure of some modules may not hamper the RADAR's performance, however there is a "safe limit" of 10% .. more than it entire RADAR's may fail .

as for PESA type RADAR, the primary advantages over AESA is price .. AESA is EXPENSIVE.. cost of the AESA  can up to millions of $ , primarily determined by emitted power and numbers of transmit and receive modules  .

You can try calculate it using following equation, for generalized phased Array system (AESA or PESA) :

Ch=Ct*Nt+Cpav*Pav*Nt+Cr*Nr


Ch=Cost of Hardware ($)
Ct=Cost of Transmitter module
Nt=Number of Transmitters
Pav=Average emitted power (PPeak*Duty Cycle)
Cr=Cost of Receiver Module
Nr= Number of Receivers
Cpav=Cost of producing average power (U$/watt)

Let's have an example.. now we have AESA RADAR with 2000 T/R Modules with peak power of 20 Kilowatts and duty cycle of typical Russian fighter jets (25%), cost of the T/R modules is U$ 500  

In the other hand we have a PESA RADAR with single transmitter having 2 Travelling wave tube each delivering 10Kw of power thus Peak power of the RADAR's is 20Kw .. cost of the transmitter is U$ 250.000 , the PESA have 2000 receive module with cost of U$ 300 each .

duty cycle is same .

cost of producing average power for both RADAR is assumed to be the same U$ 0,1/watt

so which one is cheaper ?

AESA RADAR
Pav= 20.000 watt* 0.25 = 5000 Watt
Cost of AESA : U$ 3.000.000

PESA RADAR
Pav= same as above (5000 watts)
Cost of PESA : U$ 850.500

the PESA RADAR with same power and same duty cycle comes in much cheaper .

perhaps that is why SAM engagement RADAR's which may consist of some 10.000 antenna modules uses PESA scheme instead AESA.

Stealthflanker wrote:

SerbNationalist wrote:Tell me Garry, what is the difference between PESA and AESA, which is better? Sorry for the question but trying to learn that stuff, am really interested in it.

Related to PESA or AESA , the primary differences between them is their power source , PESA RADAR uses Single transmitter to transmit their beam , their Antenna elements contains no "Active" elements, only Phase Shifters for their electronic Scanning .

Example is Irbis-E RADAR which uses 2 Travelling Wave Tube to form its transmitter system, it's antenna contains nothing but a beam steering controller and phase shifters .

as for AESA every antenna elements mounted on it have their own transmitter in shape of MMIC (Monolithic Microwave Integrated Circuit) along with power amplifier , thus every element can transmit power by itself , and those devices are mounted in the Antenna (PESA transmitter is NOT in the Antenna but in separate module/LRU) .

as for AESA Vs PESA comparison , the primary advantages held by AESA over PESA is in the Reliability of the transmitter, PESA transmitter (Travelling Wave Tube, Klystrons, Magnetrons ) are usually "short lived" due to the fact that they often handle very high amount of Microwave power in often very confined or small space, like say fighter RADAR's , their MTBF (mean Time Between Failure) is somewhere between 200-300 Hrs , and can be as low as 5 hours (early Su-27's N001 Myech RADAR's) once the transmitter fail , the entire RADAR will cease to function .

AESA RADAR in other hand , since MMIC modules handle lower power (5 watts till some 100 watts) their reliability is higher , APG-79 MMIC T/R Modules may last with MTBF up to some 20.000 Hours , another advantage is since each modules have its own transmitter, failure of some modules may not hamper the RADAR's performance, however there is a "safe limit" of 10% .. more than it entire RADAR's may fail .

as for PESA type RADAR, the primary advantages over AESA is price .. AESA is EXPENSIVE.. cost of the AESA  can up to millions of $ , primarily determined by emitted power and numbers of transmit and receive modules  .

You can try calculate it using following equation, for generalized phased Array system (AESA or PESA) :

Ch=Ct*Nt+Cpav*Pav*Nt+Cr*Nr


Ch=Cost of Hardware ($)
Ct=Cost of Transmitter module
Nt=Number of Transmitters
Pav=Average emitted power (PPeak*Duty Cycle)
Cr=Cost of Receiver Module
Nr= Number of Receivers
Cpav=Cost of producing average power (U$/watt)

Let's have an example.. now we have AESA RADAR with 2000 T/R Modules with peak power of 20 Kilowatts and duty cycle of typical Russian fighter jets (25%), cost of the T/R modules is U$ 500  

In the other hand we have a PESA RADAR with single transmitter having 2 Travelling wave tube each delivering 10Kw of power thus Peak power of the RADAR's is 20Kw .. cost of the transmitter is U$ 250.000 , the PESA have 2000 receive module with cost of U$ 300 each .

duty cycle is same .

cost of producing average power for both RADAR is assumed to be the same U$ 0,1/watt

so which one is cheaper ?

AESA RADAR
Pav= 20.000 watt* 0.25 = 5000 Watt
Cost of AESA : U$ 3.000.000

PESA RADAR
Pav= same as above (5000 watts)
Cost of PESA : U$ 850.500

the PESA RADAR with same power and same duty cycle comes in much cheaper .

perhaps that is why SAM engagement RADAR's which may consist of some 10.000 antenna modules uses PESA scheme instead AESA.

First of all I never mind, it would be nice to come and read this topic tomorrow and find 50 more responses from different people.  
Second, thank you for that post, it is very educational and is something I looked forward to!
So generally they have the same effectiveness? I mean they both have the same quality in waging war. PESA will need more maintenance and more spare parts in high level battles while AESA will need less but costs over 3 times more than PESA? They are both LPI (Low Probability of Interception) if I'm not mistaken, and they more or less have the same performance? If I'm not mistaken most if not all AD systems use PESA? I'm guessing that in combat it is as reliable as AESA, just needs more maintenance and spare parts?
I said as reliable having in mind that strategy will be multiple radars scanning areas when they spot groups or individual targets they track, then they shut down and leave the job for Buk's guidance PESA radar's, guidance radars work for few seconds until they launch (for ARH) or few extra seconds while they guide the target if its SARH! I knew that every Buk has its on radar I just didn't know weather they were PESA or something else.
And since I really love Buk, I'm interested in your opinion would a good combo be something like AESA radars for surveillance and acquisition radars and PESA as guidance radars, and of course a good command and control center...mobile of course_!
Thank you in advance and sorry for being boring, I just really like Buk and want to learn everything about it, and I also like radars, and am about to serve on one in few months when I report for military duty after I'm done with college!
And by Buk I always mean M2 or M2E or M3, although no one knows anything exact about the M#, just guesses and small info that has been released.

Tell me Garry, is Buk equipped with an AESA radar, or if it isn't, can
it be equipped? And by Buk I mean do TELARS have it, I know that it can
be used as a surveillance radar! And tell me what is the difference
between PESA and AESA, which is better? Sorry for the question but
trying to learn that stuff, am really interested in it.

The difference between Kub and Buk is cost... having a radar on every TEL made the system much more capable and much more survivable, but also much more expensive.

PESA and AESA are both electronically scanned arrays and share many advantages over mechanically scanned radar.
AESA is best but expensive. PESA is 70% as good and much cheaper. In terms of guiding missiles all the advantages of low sidelobes is shared by both ESAs.
PESA is much cheaper.

Interesting , Source ?

That book that I mentioned that showed the US turned off civilian GPS over Georgia during the conflict in 2008 to make it harder for the Russians (the Georgians were using military navstar receivers) mentioned it from memory, or it might have been in a CAST article... I will have a look.

Related to PESA or AESA , the primary differences between them is their
power source , PESA RADAR uses Single transmitter to transmit their beam
, their Antenna elements contains no "Active" elements, only Phase
Shifters for their electronic Scanning .

In many ways the difference is like the difference between having a grid array of lenses with optical fibres leading to a single bulb where the bulb can electronically send light down one or all of the fibres to shine light in a different area. It can electronically scan the field of view in milli seconds and then examine the results.

That is a PESA.

An AESA is a grid array of flashlights where each has the power to transmit and receive light. Obviously it is an order of magnitude more expensive and complicated but each element can do some preliminary processing to reduce noise and lower power settings can be used.

perhaps that is why SAM engagement RADAR's which may consist of some 10.000 antenna modules uses PESA scheme instead AESA.

To add to this the Russians have been using PESA radars for 30 years and have improved them over time so their performance is actually very impressive. Their technology with regard to AESA radar antennas is much more limited and "new".
In performance terms a Russian PESA vs a Russian AESA the Russian PESA is probably a better choice for now and not just because of cost. A Good PESA is likely better than an average AESA.

The Russians have invested a lot of money and effort into AESA technology and some of the PESA technology can certainly be applied to AESAs so they are not starting from square one.

Soon next gen SAMs and ships and aircraft etc will be fitted with AESAs as standard.

So generally they have the same effectiveness? I mean they both have the same quality in waging war.

Think of it in terms of stealth. For some roles... like air policing duties or intercepting unescorted bombers stealth is pretty pointless. For other duties like penetrating enemy air defences, or shooting down enemy fighter aircraft stealth is pretty useful to have... though C4IR and net centricity and situational awareness is just as important.

The thing is that PESA is almost as good as AESA and most of the time it is good enough. There are some roles where AESA makes a real difference... for instance using powerful radar emissions as jammers is much easier with 2,000 emitters than with one emitter through 2,000 lenses.

AESAs tend to be better in low probability intercept modes (LPI) where very low energy beams are used to scan and track targets using different frequencies and wave shapes to find different targets. The use of the right frequency and the right wave shape means you look sharper... the alternative is raw power which makes your scan or track signal like a lighthouse beam to a man with a pair of binoculars.

Because each of the antenna elements is a complete transmit receive module it can form complex signals and process the return signal to remove noise and unwanted data, which means less powerful emissions are required and the correct signal can be used to get the best data on the target.

For instance some radar frequencies bounce off rain clouds and are used by weather radars to monitor weather... other frequencies go through clouds and moisture but tend to bounce off the ground and aircraft. Different materials reflect different frequencies differently... and of course there is Doppler shift which will tell you if the target is moving and in which direction.

Tell me is PESA considered an LPI (Low Probability of Interception)radar? (question inspired by your comment on side lobes, which is the characteristic of LPI radars, low side lobes ) I know that SAM's don't need jamming capabilities, but LPi is very important these days, that's why I asked about AESA and PESA.

Low (energy) side lobes is a feature of ESA radars, so both PESA and AESA radars benefit.

In many ways sensor fusion can offer LPI modes to any radar in the sense that the combination of an IRST with any type of radar means that a target that is detected by the IRST can be tracked by a radar without needing a full field of view scan or high energy pulse.

For a conventional dish radar to find targets it transmits radar beams and mechanically scans one side to the other top to bottom or bottom to top. As it transmits it listens for return signals so the scan has to be slow enough to allow the signal to go out and come back from the target.

With an AESA or PESA each element covers an area of the field of view so to scan the entire FOV at once you just turn the elements on and off and then listen for the return signal.

In both cases the return signals for targets are remembered and to "track" the target you occasionally send another pulse in the area of sky the target was to see if it is still there or if it has moved.

With an IRST detecting targets the radar no longer needs to scan and send out energy in random directions that can be detected by an enemy... the IRST finds the target but cannot give a precise range so using the angular information from the IRST the radar can send a tracking pulse directly at the target and get range and speed and other information in a single fraction of a second pulse that might be missed by the enemy in the noise of other radars and jammers etc.

From the Feb. issue Take Off mag...

The MiG-31BMs upgraded in Phase I (i.e. furnished with the improved Zaslon radar and an advanced cockpit display system at the backseater’s combat station) have been fielded with combat units.

In December 2012, successful launches of new long- and medium range air-to-air missiles crowned the Phase II trials.

The official tests report is to be approved in the near future, and aircraft upgraded this way will start fielding with line units too.

And this on the Irbis...

Will you dwell on the Irbis radar that is surely the summit of the passive electronically scanned radar technology?

You are right, the Irbis is second to none in the world, indeed, as far as its test-proven characteristics are concerned. Last year, the fight trials involving the Su-35 fighter produced the unique aerial target acquisition results – much more than 400 km!

This is the unrivalled achievement of the world’s aircraft

.....Last year, the fight trials involving the Su-35 fighter produced the unique aerial target acquisition results – much more than 400 km!
This is the unrivalled achievement of the world’s aircraft

Professor Yuri Bely has, since several years, pointed out the outstanding tracking performances of "Irbis" radar and how them was largely head of the most advanced foreign competitors.


That is what it wrote about range comparison with AESA radars mounted on USAF F-15s and the future AESA (AN-APG-81) to be mounted of F-35:

При этом ряд заявленных характеристик не только не уступает, но и превосходит характеристики лучших зарубежных аналогов.
Так, заявленная в ТТЗ системы «Ирбис-Э» дальность обнаружения малоразмерной воздушной цели класса «истребитель» значительно превосходит аналогичные характеристики зарубежных аналогов. Обнаружение адекватного противника (истребителя) станцией AN/APG-62(V)1 модернизированного самолёта F-15C составляет 100-120 км, а модификации с БРЛС, снабжённой АФАР (AESA) - 160 км. Более «продвинутая» станция с АФАР многофункционального истребителя F-35 (JSF) может работать в см-диапазоне на дальности 170-180 км.

That is comparison with the most advanced western fighter aircraft mounted radar (AN-APG-77) and how the interaction with relative average RCS of the two aircraft would influence relative detection ranges.

Интересно сравнить «дуэльные» возможности авиационных комплексов Су-27СМ2 (Су-35) и F-22A «Сухой», оснащенный «Ирбисом», может обнаружить цель с ЭПР 0.1-0.5 м2 (приблизительно в этом интервале лежит величина эффективной радиолокационной поверхности рассеяния малозаметного самолета Локхид Мартин F/A-22A) на дистанции 165-240 км.
В то же время, американский истребитель «видит» своего противника с ЭПР 1 м2 на дистанции лишь 200 км (Jane's All the World's Aircraft 2005-2006). Таким образом, малозаметный «Рэптор» со своей АФАР по части бортового радиолокационного комплекса не имеет никаких реальных преимуществ перед модернизированным «Сухим» в ракетном воздушном бою на «вневизуальной» дальности

Is interesting to note that the precise requirements ,by part of MoD, for "Irbis" not only for similar tracking performances but also to being capable to engage, contemporaneously, up to four air targets with very long range missiles ( ranges superior to 300 km ) and the plan to equip modernized TU-22M3M with that radar suggest a possible employment of those long range supersonic bombers also in the critical role of surveillance assets useful at discover and pass the position of inbound groups of cruise missiles even while carrying out their own missile delivery attack missions

The integration of similar radar (likely also improved in the next years) in improved TU-22M3M would confer to them a real and critical dual-role attack/defense capability , exploiting to the maximum theirs high speed and optional low altitude flight profile capability .

Good info there guys...and thanks Mindstorm for the radar range comparison.

Good info there guys...and thanks Mindstorm for the radar range comparison.

What i think is even more important to point out ,starting from those data, is how "low observability" ,IN REALITY, contribute to confer to a fighter aircraft implementing it a decisive tactical advantage against enemy aircraft equipped with radar suit with "standard" tracking range capabilities. (it is very different from the fairy tales circulating on the subject).



In a "Classical" USAF exercise an F-22 is put against an F-15C ; them start in a route of recyprocal interception ,let put, 450 km away.


F-22 with few controlled pulses of its AN-APG-77 radar is capable to detect an F-15C more than 300km far , on its side an F-15 equipped with legacy AN-APG-63(V)1 (which would very likely alert F-22's AN/ALR-94 from second one) with its 120 km co-altitude closing detection range -5 square meters target - would detect an F-22 at less than 43 km ; one equipped with a (V2) or (V3) AESA radar would, very likely, still be incapable to detect the "Raptor" before 80-85 km range.

F-22 ,maintaining track of the precise vector of the opposing F-15C (or F-15Cs, if it is a "one vs many" exercise) with its AN-ALR-94 and/or disciplined employment of its AN-APG-77 AESA radar ,can at this point capitalize this huge detection range advantage and its crushingly superior dynamic performances to literally circumvent the cone of coverage footprint of F-15's AN-APG-63 main radar attacking so the "enemy" with AIM-120s delivered at very high speed, high altitude and relatively rear close range and egressing quickly ; all of that from well outside the radar field of view of the "unaware" F-15s attacked .



Is in THIS WAY that low observable aircraft achieve theirs kills..... "without that the enemy was even only aware to being under attack"; it represent simply the exploitation of a decisive tactical advantage offered by stealth ,but obviously nothing to do with the laughable fairy tales usually circulating on the subject


Anyone now can realize how the interaction of the Irbis-E much greater tracking range (almost totally offsetting by itself the difference in tactically relevant RCS between the two aircraft) and its capability to combine E-scanning with mechanical steering to enormously expand the field of view, render the up mentioned tactic totally unfeasible (naturally the RCS of the stealth aircraft while executing the outflanking maneuver previously described grow substantially , therefore in order to succeed low observable aircraft must enjoy an enormous detection range advantage over its opponent.)


It is also the main reason for integration of all around sensor suit (or at least exapanded Field of View AESA radars ,like for the EF Thyphoon CAESAR ) in all latest design expected to "cross the arms" with enemy low observable aircraft in the next years.

Mindstorm how does Irbis radar differ from the AESA radar of PAK-FA becuause the MKI upgrade is also suppose to get AESA radar from PAK-FA.

sepheronx wrote:Question regarding PESA vs AESA

I know Irbis-E is a very powerful PESA, but besides its detection/tracking ranges, how does it fair compare to its competitors that are in AESA form?  As well, since it lacks LPI mode, is it not easier to track an aircraft using PESA vs one using AESA?  As well, due to AESA's better ECM capabilities, how did Russia improve Irbis-E's ECM capabilities over that of the Bars radar?

As far as I can remember Ирбис-Э (Irbis-Eh) is not a PESA; it is not an AESA either. ESAs do not consist of only PESAs and AESAs; there are many other types of ESA radar types.


Irbis-Eh can be classified as ~((3A + P)/4)ESA if a person insists on carrying on from a PESA/AESA type of terminology! As far as I can remember, it is semiactive in transmit and active on receive.


In relation to LPI-capability and ECM resistance, an Irbis-Eh-type radar is indistinguishable from an AESA type.


Academically speaking, one of the thing that has the potential of distinguishing a run-of-the-mill AESA from an Irbis-Eh-type radar (not necessarily an Irbis-Eh though) is the potential reliability aspects related to the lifetime of the transmitter TWT(s).


I should also mention that an Irbis-Eh-type radar has potentially also advantages over a run-of the-mill AESA in certain areas.

sepheronx wrote:I know that this is not the first time I heard Irbis-E called a Hybrid, and I think I am understanding now why it is.  

It's a hybrid array because it's basically a PESA in transmit and an AESA in receive. It's not a full AESA because the individual receiver modules are not providing the signal (making them different from an AESA's transmit/receive modules), the signal comes from the separate power source via the TWTs and waveguides.

Most of this is crap I haven't used for years. This week I'll dig out some of my radar design textbooks and come up with a better explanation of some of this mess if Morpheus hasn't gotten around to it by then.

sepheronx wrote:Morpheus Eberhardt, I would so much look forward to when you do a document of some sort telling the differences of AESA to PESA, benifits vs not and various different methods inbetween (Hybrids).

I know that this is not the first time I heard Irbis-E called a Hybrid, and I think I am understanding now why it is.  Thank you for the info, and please, I would love to understand more so whenever you get the time.

sepheronx,

Thanks. I'll do that; just that I have been a bit swamped with work recently.

SOC wrote:

sepheronx wrote:I know that this is not the first time I heard Irbis-E called a Hybrid, and I think I am understanding now why it is.  

It's a hybrid array because it's basically a PESA in transmit and an AESA in receive.  It's not a full AESA because the individual receiver modules are not providing the signal (making them different from an AESA's transmit/receive modules), the signal comes from the separate power source via the TWTs and waveguides.

Most of this is crap I haven't used for years.  This week I'll dig out some of my radar design textbooks and come up with a better explanation of some of this mess if Morpheus hasn't gotten around to it by then.

SOC,

That is not correct. Vide supra.

SOC wrote:

sepheronx wrote:I know that this is not the first time I heard Irbis-E called a Hybrid, and I think I am understanding now why it is.  

It's a hybrid array because it's basically a PESA in transmit and an AESA in receive.  It's not a full AESA because the individual receiver modules are not providing the signal (making them different from an AESA's transmit/receive modules), the signal comes from the separate power source via the TWTs and waveguides.

Most of this is crap I haven't used for years.  This week I'll dig out some of my radar design textbooks and come up with a better explanation of some of this mess if Morpheus hasn't gotten around to it by then.

That only improves sensitivity (separate receiver), the all main advantages of Aesa radar types over Pesa , lye in the emmiting part of it (emission part).

I don't have experience with neither PESA neither AESA radar, but as I know, PESA radar is also capable of frequency hoping as well as electronically control transmitting pulse in miliseconds and send them with low energy in different places for very short time, to be more difficult to detect, specially for older RWRs, so those moduls still control transmitting signals although not transmit themselves. Maybe PESA is better for engagement radar, because one larger transmitter could easier focus high power in one point than 1000 smaller ones, what is quite important for missile guiding and to overcome jamming signal.

there is a loss when a feed signal goes trough phase shifters in the antennae ,newer aesa also is better at focusing and can work at 110% for a short time  

I think in that case AESA need good cooling system around T/R modules to not overheat. Maybe PESA have here for now advantage, because transmitter is outside and could keep high power for longer time. But with time cooling will become better and AESA more standard for Russian military. At the moment they have only early warning AESA radars, because they don't need that high power as engagement radars.

not just cooling. its about efficiency .,how much energy is turned into radiation ,and how much to waste (mostly heat)...i had a good picture but cant find it now... 

That goes one with another. If you could not effectively cool it, efficiency drop and the system go out. AESA need less power to send a signal of 1W per square meter than PESA, but to increase power of signal you need more cooling for T/R moduls to not overheat, while in PESA transmitter is outside and with that easier to cool down receiving modules.

ok found it (finally:lol: )


now for modified pesa the receiver cutoff is before the waveguide so noise is half d.