F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 00:30
by mrbsct
I read on Defense issues by Picard578(a ridiculous avionic "expert" who shows a bunch of stats to make him look smart, then comes up with random numbers to support his own agenda against Lockheed Martin and the "military industrial complex", basically an internet Pierre Sprey), say that IRST is so effective now systems like the PIRATE can pretty much nullify stealth at 100 km on a frontal target to the point that IR stealth such as IR Paint makes zero difference and the F22's nozzles only increase rear stealth. Also I head ridiculous claims that modern ECMs can jam radar(even LPI AESAs) to the point they are only 1/3 their range(some number he pulled out with no support)

How effective is IRST? I know it is very stealthy since it cannot be detected or jammed, but the range comes into question. How effective are IR panels? Can ECMs really be that effective on modern radar like AESAs?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 02:10
by sferrin
"LowObservable" get a new handle or something? :lmao:

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 02:51
by thomonkey
The f22 and f35 will get a radar lock on any non stealthy jet a long time before any irst is within range. I don't really think much has to be said besides that.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 08:22
by hornetfinn
Modern IRST systems are very good and can see targets long distances away. They can see very small heat differences and I'm sure that they can see F-22 or F-35 at fairly substantial distances away. However they are definitely affected by design features like nozzles, airframe and exhaust cooling and other IR reduction features. Any reduction in heat peaks is going to reduce detection and tracking range. It's impossible to tell how different heat signature F-22 or F-35 has compared to designs with minor IR reduction measures like almost any pre-5th gen fighter. IMO, it's likely that both have much lower IR signature but that's just a guess. Of course lighting up AB is going to make very bright heat source no matter what the aircraft in question is (although IR reduction measures would still have some effect).

IRST currently has some limitations like poor range resolution. Most IRSTs have quite poor magnification capabilities and thus can do target ID only at relatively short ranges. That also affects range resolution as range can be determined more accurately if there are more pixels available from the target. F-35 EOTS is an exception as it has similar magnification capabilities to targeting pods which have 5 to 20 times higher magnification capabilities to IRST systems.

One thing to notice is that most capable IR sensor cores (which set the performance of the IRST systems) are produced by USA, then folled by France, UK, Japan, Israel and Germany. Possibly include South Korea and maybe Taiwan in the list as well. After that there is huge gap before China and Russia in producing IR sensor cores. So the threat of IRST systems is rather low currently as potentially hostile countries don't have technology to produce really modern IRST systems. For example OLS-35 in Su-35 is still nowhere as good as AN/AAS-42 produced for F-14D over 20 years ago.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 08:56
by KamenRiderBlade
sferrin wrote:"LowObservable" get a new handle or something? :lmao:


No, he had a kid with a foreign lover to train to follow his footsteps.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 09:19
by hornetfinn
Any radar can be jammed totally given enough power. If one could jam AESA to the point that it could only see 1/3 of the non-jammed range would mean that non-AESA radar would not see anything but noise and false targets. Besides, the effective jamming range depends heavily on the RCS of the target protected by the jamming.

Let's assume that advanced 4th gen fighter with AESA confronts 5th gen fighter with AESA. Both have identical radar performance and identical jamming system. Since 5th gen fighter will have say 100 times lower RCS, it can be detected it can be detected/tracked about 1/3 the range 4th gen fighter can be detected/tracked when no jamming is present. With jamming employed have the same comparative jamming performance (still maintain 1:3 range advantage) using 1/100 of the power required to protect advanced 4th gen fighter. Alternatively it can jam the 4th gen fighter radar so much that it can detect or track the 5th gen fighter at less than 1/10th the range 5th gen fighter can detect/track 4th gen fighter (assuming both use all the jamming power in their jamming systems).

Of course 5th gen fighters have much more jamming power available due to integration of AESA antenna and EW suite. For example F-35 is said to have 10 times more jamming power any legacy fighter has ever had:
https://www.f35.com/about/capabilities/electronicwarfare

While F-35 is capable of stand-off jamming for other aircraft — providing 10 times the effective radiated power of any legacy fighter — F-35s can also operate in closer proximity to the threat (‘stand-in’) to provide jamming power many multiples that of any legacy fighter.


It could be argued that F-22 and F-35 have better than 100 times lower RCS than advanced 4th gen fighters and along with much more jamming power, the net effect is something unbelievable. Even AESA radar which seems impervious to jamming against 4th gen fighters might be severely affected when trying to detect F-22 or F-35 due to combination of very low RCS and high jamming power.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 14:46
by eloise
Due to the principles that they work, deceptive jamming are quite useless against AESA radar

The deceptive jammer received enemy incoming RF signal , it analyse , and then re transmitted that signal with different characteristic , like different doppler , pulse width . In contrast to noise jamming, deception jammer tries to mimic the radar echo so that the radar will respond as if it is receiving an echo from another aircraft or ship.


So deceptive jamming have to receive and process signal before they can send out jamming signal
Here are some characteristics of AESA radar that make them very resistance to jamming : frequency agility , and random PFR , random scan pattern
Jamming is likewise much more difficult against an AESA. Traditionally, jammers have operated by determining the operating frequency of the radar and then broadcasting a signal on it to confuse the receiver as to which is the "real" pulse and which is the jammer's. This technique works as long as the radar system cannot easily change its operating frequency. When the transmitters were based on klystron tubes this was generally true, and radars, especially airborne ones, had only a few frequencies to choose among. A jammer could listen to those possible frequencies and select the one to be used to jam.
Most radars using modern electronics are capable of changing their operating frequency with every pulse. An AESA has the additional capability of spreading its frequencies across a wide band even in a single pulse, which equates to lowering the emission power, making jammers much less effective. Although it is possible to send out broadband white noise against all the possible frequencies, this means the amount of energy being sent at any one frequency is much lower, reducing its effectiveness

http://self.gutenberg.org/articles/aesa_radar


In general, high PRF radars are more resistant to ECM because their average power is greater. Changing the PRF in a random fashion is an effective counter to deception because deception ECM depends on predictability of the radar. However, because PRF is related to the basic timing of the radar, this technique results in additional complexity and expense. Random PRF has been employed as a very effective ECCM feature in some radars for many years and has the additional benefit of elimination of MTI radar blind speeds.

Scan pattern. The radar scan pattern can influence ECCM capability because it influences the amount of energy directed toward the radar target. An active tracking phased-array radar is quite ECM resistant because of its ability to rapidly scan its radar beam in a random fashion than in the regular circular or sector scan pattern of conventional radars. This irregular beam positioning would give the opposing ECM system little or no warning and make it impossible to predict where and when to transmit false signals. In systems where scanning is performed in the receiver rather than in the transmitted beam, such as those mentioned in the section on angle deception, ECM has no direct access to the radar scan pattern and thus has difficulty using that information to interfere with the radar system operation.

Frequency. Frequency agility is a significant ECCM design feature. Using components such as frequency synthesizers (something like those employed in radio scanners) instead of conventional crystal-controlled oscillators, some radars are able to change frequency within one pulse repetition time (PRT). This makes deception and jamming very difficult. The radar can be designed to change frequency automatically within a certain range, or this can be done manually.

http://fas.org/man/dod-101/navy/docs/fun/part11.htm

To effectively jam an AESA radar, you would need to use noise jamming. For a noise jammer to be effective , the signal to noise ratio that enemy received must be less than 1. To achieve that you either have to increase your jamming power or reduce your reflected signal , or both. F-35 use APG-81 to jam, AESA have very narrow beam, as a result jamming power are more focused at enemy's place. It's also have a tiny RCS, thus reducing the reflected signal significantly
Even if we assume both side use the same kind of jammer, it still much easier for a stealth fighter to jam a normal fighter's radar than the other way round. Here is why :

Image
not only that lower RCS reduce burn through distance , jamming power required will decrease in the same rate as RCS reduction ,50% reduction in RCS = 50% less power required to overwhelm real radar reflection with noise ( you can work it out for yourself , 99.9% reduction in RCS= 99.9% less power required to achieve same level of effectiveness , and so on )
now let take example of 4 aircraft :
1) B-52 : RCS = 100 m2
2) Mig-31 : RCS = 10 m2
3) Mig-35 : RCS = 1 m2
4) F-35 : RCS = 0.001 m2
now compared them :
from B-52 to F-35 then RCS is reduced by 99.999% =>99.999% less power require
from Mig-31 to F-35 then RCS is reduced by 99.99%=>99.99% less power require
from Mig-35 to F-35 then RCS is reduced by 99.9% =>99.9% less power require
( if you not good at math then use this http://www.percentagecalculator.net/ the lowest row )

so again a very powerful enemy radar : if F-35 need 5 kW jammer to shield it's radar reflection with noise signals then Mig-35 will need a 5 MW jammer , Mig-31 will need 50 MW jammer , B-52 will required 500 MW jammer , you can argue that bigger aircraft can carry more powerful jammer but remember even the SPY-1 only have power of 5 MW

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 15:23
by eloise
Picard and many people in anti F-35 group wrongly believed that fighter will be detected, lock and shot down the instant they turn on their radar thus lead to their conclusion that Radar and low RCS have little use and Optic sensor along with low IR signature are the more important
However, they are wrong because :
RWR doesn't always help aircraft detect enemy's radar before themselves get detected ( even though they have the advantage that the signal only have to travel one way)
Firstly, modern AESA implement several method to make their signal appear like background noise to enemy's RWR ( due to the fact that they change frequently every second , have random scanning pattern,compress their pulse .. etc)
Image
http://www.mar.mil.br/caaml/Revista/2007/Ingles/10-Pag40.pdf
Image
http://www.emrsdtc.com/conferences/2004/downloads/pdf/tech_conf_papers/A14.pdf

Secondly, even though RWR only have to listen to signal that travel one way, thus giving them 80 dB advantage compared to radar that have to detect reflected signal that travelling 2 ways, because of that in theory aircraft carry RWR should be able to detect Radar twice the range the radar can detect them if 2 side have equal sensitivity . In real life radar could be alot more sensitive than RWR because they have better gain . Here are reason why radar antenna have better gain :
1. RWR antenna typically has a gain of about 0 dB due to wide angular coverage. Fighter AESA radar has a gain of roughly 40 dB. This means instant 40 dB advantage to the radar.

2. Radar can operate at much narrower bandwidth as it knows the frequencies it uses and RWR does not and has to operate at much wider bandwidth. RWR receivers have a sensitivity in the region of -40 to -60 dB while radar receivers have a sensitivity is roughly about -100 dB with digital receivers achieving even better sensitivity like -120 dB.

This can give additional 50 to 80 dB advantage to radar depending on exact design of the systems involved. As AESA has a very wide total bandwidth, RWR must cover that very wide bandwidth leading to much less sensitivity. As the radar signal has a quite narrow bandwidth and radar can process only very narrow bandwidth giving large advantage in sensitivity. For AESA the advantage can be for example in the 60 to 80 dB range.

3. Radar can code or modulate the signal so that it achieves significant processing gain over RWR. Either phase or frequency modulation/coding can be used. As radar knows the coding, it can filter out the signal from noise using matched filters. The RWR can’t know the coding and this gives the radar another big advantage in total gain. This is called Processing gain and it can be tens of decibels. The more complex the coding the larger the processing gain of radar is. Modern AESA radar using Digital Beamforming can use very complex coding schemes and basically only processing power and software is the limit here. A simple calculation about processing gain is dividing the spreading bandwidth (bandwidth where the signal is spread) with actual signal bandwidth.

4. When the radar main beam is not directly pointing towards the RWR, then it will only be seen through sidelobes. Given that sidelobe level can be lower than -50 dB in AESA radars (about -20 to -30 dB in fighter MSA/PESA radars), this gives the radar a healthy advantage against RWR/ESM systems which it’s not painting. This means RWR will only see very short flashes of main beam and makes it more difficult for the RWR to work effectively.

Calculated together, radar can suddenly have well over 100 dB advantage over RWR system through mainlobe and over 150 dB advantage otherwise. There are ways for RWR/ESM systems to get some of that back and of course the race is never ending. RWR/ESM system can use more directional antenna, more sensitive receivers and higher processing power.[code][/code]


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It also important to remember that even if your RWR, ESM system managed to detect enemy fighter's AESA radar, the only thing you know is bearing, it very hard to measure range for a missiles launch solution . Geolocated enemy aircraft by ESM, RWR is alot harder than geolocated ground target
First let see how a modern RWR, ELINT can geolocate a ground radar to generate fire solution for anti radar missiles :
there are 6 ways:
Image
Image
however you cant really use most of them to geolocated an aircraft
here is why :
1- triangulation method required target to be stationary , and take very long time
2- Azimuth / Elevation method will not work because you dont know enemy fighter altitude ( for a ground target you know the altitude is 0 ) thus cant use the Sine and Cosine function to work out the distance to target
3 - Time different arrival method required at least 3 aircraft stay at significant distance from the other ,but doesnt work well again AESA radar due to it very small side lobe , and thin beam, it also required many aircraft working together
4- determine distance by signal strength : required to threat radar characteristic to be known , and still doesnt work again modern AESA radar because they can managed transmitting power at short range to reduce probably of detection

there are some 2 additional methods to determine distance by RWR included :
5- phase rate change
6- RF doppler processing
they can be used again enemy's aircraft, using quite similar principles, will be discussed in the paper bellow :

http://subs.emis.de/LNI/Proceedings/Pro ... 54-222.pdf
http://users.isy.liu.se/en/rt/fredrik/r ... gsonly.pdf

Image
As you can see the method have many requirements such as
1) enemy's fighter fly at constant speed the whole time
2) enemy's fighter doesn't change heading the whole time ( the method measures range by calculate the changing of bearing between enemy fighter and ELINT aircraft when ELINT aircraft fly side to side " zic zack pattern" , thus it wouldn't be possible to apply the method if enemy fighter change heading and point their nose to ELINT aircraft direction all the time)
3)enemy's fighter will constantly emitting for the whole time needed for ELINT aircraft to measure range :
4) ELINT aircraft have to perform specific maneuver for a period of times to measure range
5) Accuracy is terrible , 20-40% error in range is very significant, at 100 km distance that is 20 - 40 km error, at 50 km distance that still 10-20 km error, that is even worse than long wave VHF radar thus not very useful for long range BVR engagement again enemy's fighter

How to counter RWR passive ranging :
let call the aircraft carry RWR sensor : ELINT aircraft

Method 1:
Image
To collect data for range measurement the ELINT aircraft must fly zigzag side to side to measure change in bearing , thus showing it's side aspect RCS to enemy's radar. And the S maneuver will only work if the enemy fighter fly straight and doesn't change their heading, fly at constant speed.
remember that side aspect RCS of any aircraft is very high (often in the range 20-30 dBsm or 100-1000 m2) , so the ELINT aircraft if wasn't detected by enemy radar earlier will be detected the moment it perform the S shape maneuver. Since most aircraft radar nowadays have no trouble tracking airborne target with RCS =100-1000 m2 from 300-400 km
So after detecting the ELINT aircraft, all enemy pilot have to do is changing their heading according to the heading of ELINT aircraft ( if the ELINT aircraft turn left, you turn left, if the ELINT aircraft turn right, you turn right, accelerate or decelerate to make your speed not constant)
that action will neutralise ELINT aircraft passive ranging ability


Method 2 :
Image
alot more simple, since the ELINT aircraft take at least 15 seconds of constant receiving enemy's radar signal to measure range with error about 25-40%, if enemy's pilot turn their radar on and off constantly, the ELINT aircraft wont be able to measure range in that case
modern AESA take 2-3 sec to scan it's whole FoV so you can turn radar on for 2 seconds and then off for 10 seconds then on again
and still have good tracking of target
Image


=> to sum up, RWR cannot replace Radar in air to air BVR engagement because they are alot more time consuming, less accurate, easily be neutralise by enemy tactics

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 16:33
by mrbsct
^Doesn't F22 RWR ALR-94 have 360 coverage? A read by Military Expert and Aviation magazine editor Bill Sweetman, the ALR-94 can not only passively receive but cue the APG-77 to make it even more LPI, and even lock on to targets whether they are generating radar or not.

eloise wrote:
To effectively jam an AESA radar, you would need to use noise jamming. For a noise jammer to be effective , the signal to noise ratio that enemy received must be less than 1. To achieve that you either have to increase your jamming power or reduce your reflected signal , or both. F-35 use APG-81 to jam, AESA have very narrow beam, as a result jamming power are more focused at enemy's place. It's also have a tiny RCS, thus reducing the reflected signal significantly
Even if we assume both side use the same kind of jammer, it still much easier for a stealth fighter to jam a normal fighter's radar than the other way round. Here is why :

So stealth fighters not having dedicated jammers but use their own radar to jam are more effective than dedicated jamming systems like the SPECTRA?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 17:06
by eloise
mrbsct wrote:^Doesn't F22 RWR ALR-94 have 360 coverage? A read by Military Expert and Aviation magazine editor Bill Sweetman, the ALR-94 can not only passively receive but cue the APG-77 to make it even more LPI, and even lock on to targets whether they are generating radar or not.

RWR of any fighter in general have 360 coverage , and yes they can be used to cue the radar or IRST sensor to focus at a specific angle, bearing thus allow them to have longer detection, tracking range

however in most case RWR cant generate fire solution again enemy's fighter by themselves due to the lack of ability to measure range to moving air target
( i have stated the way RWR can be used to passively measure range and the counter measures above)
the reason why the ELINT aircraft in my example have to fly zic zack left and right to measure range isnot because it's RWR dont cover 360 degree, but because it need to know the changing in closure rate in respect the change in bearing to measure range ( sorry if it still sound a bit confusing )
mrbsct wrote:So stealth fighters not having dedicated jammers but use their own radar to jam are more effective than dedicated jamming systems like the SPECTRA?

Delicated jammer is a really vague term . Aircraft ESM systems consist of receiving antenna , the central processor, and the transmitting antenna. The receive components on Rafale is SPECTRA, on F-35 is Asq-239. They both have central processor to detect, classify, generate jamming technique. however the transmitting part is a bit different, on Rafale the jamming signal is transmitting through the antenna spread through the aircraft airframe. On F-35 the jamming signal is transmitting through the radar T/R modules or towed decoy such as ALE-70. The advantage of SPECTRA is that jamming signal can be transmitted to any direction, the advantage of using APG-81 as a jammer is that jamming signal will be more powerful and focused due to better gain of radar. Also, the main reason that make stealth fighter's jamming more effective is their tiny RCS compared to legacy fighter
hope that clear up

Re: F22 vs. IRST and radar jammers

Unread postPosted: 27 May 2015, 23:21
by mrbsct
I believe the F22's RWR the ALR-94 can provide accurate data for attack.

Journal of Electronic Defense; Bill Sweetman

The F-22 represents a radical departure from the traditional approach to EW. Passive systems, once considered to be defensive in nature, are now critical to detecting, tracking and even attacking the target.

High-priority emitters -- such as fighter aircraft at close range -- can be tracked in real time by the ALR-94. In this mode, called narrowband interleaved search and track (NBILST), the radar is used only to provide precise range and velocity data to set up a missile attack. If a hostile aircraft is injudicious in its use of radar, the ALR-94 may provide nearly all the information necessary to launch an AIM-120 AMRAAM air-to-air missile (AAM)

But aren't radar based jamming more prone to be detected by RWR and can risk an attack from anti-radiation missile?

Here is a quote from Air Power Australia:
Currently classified capabilities such as the use of the APG-79 or APG-81 AESA radar as an X-band high power jammer against the Russian BARS or Irbis E radar are not a panacea, and may actually hasten the demise of the F/A-18E/F or F-35 JSF in a BVR shootout. This is for the simple reason that to jam the Russian radar, the APG-79 or APG-81 AESA radar must jam the frequencies being used by the Russian radar, and this then turns the APG-79 or APG-81 AESA radar into a wholly electronically predictable X-band high power beacon for an anti-radiation seeker equipped Russian BVR missile such as the R-27EP or R-77P. The act of jamming the Russian radar effectively surrenders the frequency hopping agility in the emissions of the APG-79 or APG-81 AESA radar, denying it the only defence it has against the anti-radiation missile. A smart Russian radar software designer will include a "seduction mode" to this effect, with narrowband emissions to make it very easy even for an early model 9B-1032 anti-radiation seeker.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 04:39
by eloise
mrbsct wrote:I believe the F22's RWR the ALR-94 can provide accurate data for attack.

If you read the article more careful , it does say ALR-94 provide nearly all but not all information required for missiles launch , radar still needed for velocity and distance measure


Journal of Electronic Defense; Bill Sweetman

The F-22 represents a radical departure from the traditional approach to EW. Passive systems, once considered to be defensive in nature, are now critical to detecting, tracking and even attacking the target.

High-priority emitters -- such as fighter aircraft at close range -- can be tracked in real time by the ALR-94. In this mode, called narrowband interleaved search and track (NBILST), the radar is used only to provide precise range and velocity data to set up a missile attack. If a hostile aircraft is injudicious in its use of radar, the ALR-94 may provide nearly all the information necessary to launch an AIM-120 AMRAAM air-to-air missile (AAM)

( it very easy for a RWR to geolocate a stationary ground target , again a moving air target that is a whole different story)

mrbsct wrote:But aren't radar based jamming more prone to be detected by RWR and can risk an attack from anti-radiation missile?

Here is a quote from Air Power Australia:
Currently classified capabilities such as the use of the APG-79 or APG-81 AESA radar as an X-band high power jammer against the Russian BARS or Irbis E radar are not a panacea, and may actually hasten the demise of the F/A-18E/F or F-35 JSF in a BVR shootout. This is for the simple reason that to jam the Russian radar, the APG-79 or APG-81 AESA radar must jam the frequencies being used by the Russian radar, and this then turns the APG-79 or APG-81 AESA radar into a wholly electronically predictable X-band high power beacon for an anti-radiation seeker equipped Russian BVR missile such as the R-27EP or R-77P. The act of jamming the Russian radar effectively surrenders the frequency hopping agility in the emissions of the APG-79 or APG-81 AESA radar, denying it the only defence it has against the anti-radiation missile. A smart Russian radar software designer will include a "seduction mode" to this effect, with narrowband emissions to make it very easy even for an early model 9B-1032 anti-radiation seeker.

No radar based jamming are not anymore prone to be detected by RWR than a normal jammer like ALG-184 or Spectra .
However , you are right about the part that when you use jamming , you are at risk get attacked by anti radiation or HOJ missiles .
That being said however : noise jamming to denied enemy ability to attack you by over saturate their receiver with noise signal , what does that mean : it mean enemy will know your direction , but they wont know the distance to your aircraft or your velocity , aspect angle .If they still decided to launch missiles anyway without knowing the range, speed then their missiles will have to fly a direct path rather than an arcs like they normally do thus reducing their range and terminal velocity significantly , moreover missiles in HOJ mode ( or anti radiation missiles ) will home at the radiated source without knowing direction the enemy going , aspect angle or speed of target thus they are unable to do a lead intercept and that will further reducing their PK again maneuver targets .
the threat from anti-radiation missiles could also be solve by using a FOTD . For example : ALE-55, TRD, X-Guard, ALE-70.. etc or an automous jamming UAV such as MALD-J to do the jamming work .

Anti-radiation missiles can also be defeated very easy by a simple tactic : jamming in turn ( not sure if i remember the tactics name correctly but it have been used since Vietnam war again anti radar and HOJ missiles )
As we know missiles in HOJ mode doesn't know the speed or range to target, it just home at the radiated signal ( basically like an anti radar missiles)
As long as there are 2 jamming asset fly at a certain distance from the other , they can turn their jammer on and off , in turn to attract and defeat the enemy's missiles,
For example : Imagine this : 2 fighter get in detection range of a SAM site. Fighter A start jamming to neutralise enemy radar. SAM crew decided to launch missiles in HOJ mode to counter that. When the enemy missiles home on the fighter A direction, the pilot of it will turn off his jammer, fighter B will turn jamming on , missiles will now steer to the direction of fighter B , now the fighter B turn off jamming and the fighter A turn on jamming again... etc very quickly after 1-2 time the SAM or AAM will run out of fuel and fall down the sky
P/s: the same thing can be done by 2 f-35 or 1 F-35 carry a MALD-J

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 04:57
by eloise
Also , while radar guide air to air missiles often have HOJ mode to deal with the situation when jamming is too heavy , a delicate anti radiation missiles ( something like R-27P , R-27EP ) are very close to useless again fighter because :
1) unlike an AWACs , fighter's radar only have FoV of about 60 degree , which mean the missiles will fly unguided the moment enemy fighter turn it's nose to other direction
2) unlike a ground radar , a fighter is moving very fast , when the ground radar turn off while the anti radar missiles still in mid fly ,the anti radiation missiles can use INS to guide itself to fly into the last known location if the radar , because ground radar are either stationary or moving very slow so that tactic would work. But again a moving aircraft , that tactic is close to useles.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 05:55
by eloise
optical sensor ( IR, EO) also have a few weakness that stop them from replacing radar as the main sensor :
1) optical sensor may have very long detection range ( aas-42, private can reach out 200 km) but their targeting range ( where they can give firing solution) are very short because it is limited by the range of LRF, often about 20-30 km
2) Optical sensor have to zoom ( focused) when they want to look at target far away, when zooming they have very narrow FoV, and the scan rate of optical sensor are significantly slower than an AESA / PESA radar
3) optical sensor are heavily affected by weather, cloud, smoke, enemy can fly near cloud to hide from them

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 09:21
by hornetfinn
mrbsct wrote:I
But aren't radar based jamming more prone to be detected by RWR and can risk an attack from anti-radiation missile?

Here is a quote from Air Power Australia:
Currently classified capabilities such as the use of the APG-79 or APG-81 AESA radar as an X-band high power jammer against the Russian BARS or Irbis E radar are not a panacea, and may actually hasten the demise of the F/A-18E/F or F-35 JSF in a BVR shootout. This is for the simple reason that to jam the Russian radar, the APG-79 or APG-81 AESA radar must jam the frequencies being used by the Russian radar, and this then turns the APG-79 or APG-81 AESA radar into a wholly electronically predictable X-band high power beacon for an anti-radiation seeker equipped Russian BVR missile such as the R-27EP or R-77P. The act of jamming the Russian radar effectively surrenders the frequency hopping agility in the emissions of the APG-79 or APG-81 AESA radar, denying it the only defence it has against the anti-radiation missile. A smart Russian radar software designer will include a "seduction mode" to this effect, with narrowband emissions to make it very easy even for an early model 9B-1032 anti-radiation seeker.


That would not work very well if at all for many reasons:

1. Russian radar would totally surrender the main reason it is designed, detect and track targets. It would be obsessed with one target (the jamming APG-79/81) and would not be able to see anything else. As fighter aircraft usually operate in formations, this would make the Russian fighters dead meat. The jamming aircraft could be flying well behind the rest or use totally different flight path.

2. This tactic would be so easily countered, it's not even funny. The jamming aircraft could just alter the heading every 20 to 30 seconds and the missile range and pK would drop like a rock. Just refer to what eloise here has said.

3. F/A-18 or F-35 could sling AMRAAM far further with precise targeting info they'd get from their AESA radars than Russian aircraft could effectively fire their anti-radiation missiles with heading only information. Like eloise described, AMRAAM could be using lofting profile going for determined collision point. Anti-radiation missile would have to fly in straight line and always go directly towards target heading. This would mean AMRAAM has huge advantage in range, end-game maneuverability and probability of kill.

4. This proposed tactic seems to assume that the jammer would use huge amount of power right away and it's easy to detect. That's not how modern jamming systems work. Much more likely is that the jamming power is small (F/A-18) to extremely small (F-35) at longer ranges and power is increased as range decreases (as radar returns get stronger). Especially F-35 would need only minuscule amount of power to hide it or any accompanying F-35 from the radar. This very small amount of jamming power would be very difficult to detect from the background noise. Very likely the radar would decrease sensitivity as the noise is increased as it would not be able to differentiate jamming from background noise as they'd be very close to each other. Every radar does this as background noise is not static but varies a lot depending on many factors like day/night, weather, background (sea, ground, vegetation), clouds, birds etc.

5. Another tactic to overcome this easily would be using co-operative jamming where each aircraft in the flight would take turns to jam the target radar. As the aircraft would fly in formations that can be even tens on miles/kilometers, it would be impossible to engage any one of them with anti-radiation missiles.

All in all, this proposed tactic is extremely poor idea and I'm sure Russian professionals are not stupid enough to believe it would work. I think the Russian missiles are intended against larger stand-off jamming aircraft which would be relatively easy targets as they do not maneuver and emit a lot of jamming power. I doubt their effectiveness against more modern jamming systems (like Growler) which work much smarter.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 11:55
by sdkf251
Just out of curiosity, isn't the R-27 HOJ missiles kind of a very "specialized" type of missile. Is this fielded as a regular load for Frontal aviation or just for special cases? Is there any Russian operational doctrine on when these missiles will be used?

I can understand if you want to take out an identified, regular scheduled flying airborne target like an AWACS, this seems to be the missile to use. But to shoot blindly at opposing aircraft seems kind of inviting the potential of the missile deciding to hit unintended targets along the way to the target. (especially long range targets)

Is there no mid-course guidance or terminal fusing for these types of missiles? ECM is not just about radar, but the whole operational electronic spectrum of the weapon system.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 14:04
by hornetfinn
eloise wrote:Delicated jammer is a really vague term . Aircraft ESM systems consist of receiving antenna , the central processor, and the transmitting antenna. The receive components on Rafale is SPECTRA, on F-35 is Asq-239. They both have central processor to detect, classify, generate jamming technique. however the transmitting part is a bit different, on Rafale the jamming signal is transmitting through the antenna spread through the aircraft airframe. On F-35 the jamming signal is transmitting through the radar T/R modules or towed decoy such as ALE-70. The advantage of SPECTRA is that jamming signal can be transmitted to any direction, the advantage of using APG-81 as a jammer is that jamming signal will be more powerful and focused due to better gain of radar. Also, the main reason that make stealth fighter's jamming more effective is their tiny RCS compared to legacy fighter
hope that clear up


F-35 uses (or can use) the AESA antenna also to receive signals. It obviously also has antennas all around the airframe to both receive and transmit signals for the ASQ-239. This gives the system also high gain (high sensitivity) receive antenna with ability to give very precise angle of arrival info about received signals. Of course it's also limited to FOV of the AESA antenna.

I have a feeling that F-35 ASQ-239 is capable of both receiving and transmitting jamming signals to all directions. Of course the frontal sector will have by far the most powerful jamming system with the APG-81 antenna.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 14:29
by charlielima223
hornetfinn wrote:Modern IRST systems are very good and can see targets long distances away. They can see very small heat differences and I'm sure that they can see F-22 or F-35 at fairly substantial distances away. However they are definitely affected by design features like nozzles, airframe and exhaust cooling and other IR reduction features. Any reduction in heat peaks is going to reduce detection and tracking range. It's impossible to tell how different heat signature F-22 or F-35 has compared to designs with minor IR reduction measures like almost any pre-5th gen fighter. IMO, it's likely that both have much lower IR signature but that's just a guess. Of course lighting up AB is going to make very bright heat source no matter what the aircraft in question is (although IR reduction measures would still have some effect).

IRST currently has some limitations like poor range resolution. Most IRSTs have quite poor magnification capabilities and thus can do target ID only at relatively short ranges. That also affects range resolution as range can be determined more accurately if there are more pixels available from the target. F-35 EOTS is an exception as it has similar magnification capabilities to targeting pods which have 5 to 20 times higher magnification capabilities to IRST systems.

One thing to notice is that most capable IR sensor cores (which set the performance of the IRST systems) are produced by USA, then folled by France, UK, Japan, Israel and Germany. Possibly include South Korea and maybe Taiwan in the list as well. After that there is huge gap before China and Russia in producing IR sensor cores. So the threat of IRST systems is rather low currently as potentially hostile countries don't have technology to produce really modern IRST systems. For example OLS-35 in Su-35 is still nowhere as good as AN/AAS-42 produced for F-14D over 20 years ago.


Two other good things to point out is that compared to a traditional radar found on fighter aircraft. IRSTs have a very narrow field of view and that they are more effected by weather conditions.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 28 May 2015, 22:58
by mrbsct
I know No Escape Zones(NEZ) is highly classified, but can anyone make precise calculations on these missiles like

AIM-120 B/C/D
Meteor
R77-1 Adder
R27 Alamo
R37 Arrow

And how does aircraft acceleration and kinematics effect the NEZ? Are missiles even effective after NEZ against a fast maneuvering opponent?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 00:04
by neurotech
hornetfinn wrote:Modern IRST systems are very good and can see targets long distances away. They can see very small heat differences and I'm sure that they can see F-22 or F-35 at fairly substantial distances away. However they are definitely affected by design features like nozzles, airframe and exhaust cooling and other IR reduction features. Any reduction in heat peaks is going to reduce detection and tracking range. It's impossible to tell how different heat signature F-22 or F-35 has compared to designs with minor IR reduction measures like almost any pre-5th gen fighter. IMO, it's likely that both have much lower IR signature but that's just a guess. Of course lighting up AB is going to make very bright heat source no matter what the aircraft in question is (although IR reduction measures would still have some effect).

IRST currently has some limitations like poor range resolution. Most IRSTs have quite poor magnification capabilities and thus can do target ID only at relatively short ranges. That also affects range resolution as range can be determined more accurately if there are more pixels available from the target. F-35 EOTS is an exception as it has similar magnification capabilities to targeting pods which have 5 to 20 times higher magnification capabilities to IRST systems.

One thing to notice is that most capable IR sensor cores (which set the performance of the IRST systems) are produced by USA, then folled by France, UK, Japan, Israel and Germany. Possibly include South Korea and maybe Taiwan in the list as well. After that there is huge gap before China and Russia in producing IR sensor cores. So the threat of IRST systems is rather low currently as potentially hostile countries don't have technology to produce really modern IRST systems. For example OLS-35 in Su-35 is still nowhere as good as AN/AAS-42 produced for F-14D over 20 years ago.

Every IRST system has advantages and disadvantages.

The IRST/ATFLIR effectiveness depends on a number of factors, such as scan volume, and if its radar slaved or not. The OLS in the earlier Flankers and Fulcrums doesn't use any Digital Image Processing, Even if the Chinese purchased a Canon camera and stuck it in a Flanker, without the Digital Image Processing, it wouldn't be as effective as the system on later F-16 aggressor jets.

Almost all the cases where a F-22 got smoked against F-5 aggressors were WVR with ATFLIR providing the lock. The radar was practically useless.

Also note that the F-35 has two different systems. EOTS and EODAS. The EOTS has a 40+ mile range against a fighter aircraft. The targeting pods on the F-16 are an earlier version. The EODAS doesn't have the same resolution at long range, but has 360 degree scan, and can point the EOTS at the target. The two systems are fused together to provide maximum situational awareness, even with low RCS targets and jammers.

My understanding is that frontline F-16 pilots don't train using their (ATFLIR) targeting pods for A/A engagements. The aggressor jets that fly against F-22s are trained to use them. Some reports say its an upgraded version of the AN/AAS-42 first used in the F-14D although my understanding is that there is multiple pods in use on the F-16 aggressor.
http://theaviationist.com/2014/02/21/re ... ed-nellis/
The F-5s were not using AN/AAS-42 pods, likely in part due to size and weight constraints

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 02:29
by eloise
hornetfinn wrote: :x

F-35 uses (or can use) the AESA antenna also to receive signals.

My bad, i forgot to mention that
hornetfinn wrote: It obviously also has antennas all around the airframe to both receive and transmit signals for the ASQ-239. This gives the system also high gain (high sensitivity) receive antenna with ability to give very precise angle of arrival info about received signals. Of course it's also limited to FOV of the AESA antenna.

I have a feeling that F-35 ASQ-239 is capable of both receiving and transmitting jamming signals to all directions. Of course the frontal sector will have by far the most powerful jamming system with the APG-81 antenna.

From what i know ASQ-239 is a passive system some what similar to ALR-94 or Falcon Edge and all sources i can find only mentioned F-35 transmitting jamming signal through APG-81, ALE-70
sdkf251 wrote:Just out of curiosity, isn't the R-27 HOJ missiles kind of a very "specialized" type of missile. Is this fielded as a regular load for Frontal aviation or just for special cases? Is there any Russian operational doctrine on when these missiles will be used?

HOJ is the anti radiation mode of radar guide missiles like Aim-120, Meteor, R-77. When their radar doesn't work they can rely on passive sensor to home on radiated source
R-27EP on the other hand is a completely passive missile, which mean it only have anti radiation mode ( basically similar to AGM-88, KH-31)

sdkf251 wrote:I can understand if you want to take out an identified, regular scheduled flying airborne target like an AWACS, this seems to be the missile to use. But to shoot blindly at opposing aircraft seems kind of inviting the potential of the missile deciding to hit unintended targets along the way to the target. (especially long range targets)
.

R-27EP can be carried with R-27ET, R-27R to increase their effectiveness when enemy have powerful jamming or AWACS asset such as EA-18G, EF-111, E-2.. etc

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 13:54
by hornetfinn
neurotech wrote:Every IRST system has advantages and disadvantages.

The IRST/ATFLIR effectiveness depends on a number of factors, such as scan volume, and if its radar slaved or not. The OLS in the earlier Flankers and Fulcrums doesn't use any Digital Image Processing, Even if the Chinese purchased a Canon camera and stuck it in a Flanker, without the Digital Image Processing, it wouldn't be as effective as the system on later F-16 aggressor jets.


This is all true. Modern IRST can be valuable tool as it provides very accurate video and images. Of course they have some drawbacks but no system alone is perfect.

All OLS systems in Flankers and Fulcrums are non-imaging systems. They can only detect sources of heat but can not create any images, just like many older heat-seeking missiles. Basically they will show the pilot a blip on the screen and nothing else. Digital image processing would not do any good for them as the detector is incapable of producing any real images. These types of detectors are also much less sensitive than modern imaging systems. Another drawback is the very low number of targets detected and tracked (like 1 to 4 vs hundreds in imaging systems).

neurotech wrote:Also note that the F-35 has two different systems. EOTS and EODAS. The EOTS has a 40+ mile range against a fighter aircraft. The targeting pods on the F-16 are an earlier version. The EODAS doesn't have the same resolution at long range, but has 360 degree scan, and can point the EOTS at the target. The two systems are fused together to provide maximum situational awareness, even with low RCS targets and jammers.


This is true and they complement each other extremely well. I think both of these systems along with sensor fusion will give some very interesting and unique capabilities for the F-35. We have seen ballistic missile/rocket detection/tracking, ground fire detection and aerial target detection/tracking. I think there are huge number of potential capabilities for the whole system, some yet not even imagined.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 15:33
by mrbsct
Is IRST capable of getting good missile lock on? IRST cannot determine range, and the range has to be determined by other sensors. I believe the PIRATE ISRT on the Tyhpoon can sense targets out to 90 km but can it use its Meteor to hit those targets?

For example if the IRST of the Tyhpoon sees a F22 or F35 at like around 80 km, and then ripple fires its entire Meteor load....do those missiles have a good chance of hitting?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 18:19
by eloise
mrbsct wrote:Is IRST capable of getting good missile lock on? IRST cannot determine range, and the range has to be determined by other sensors.

yes, it can achieve missiles lock, most IRST have a LRF that can help it measures range ( but not velocity or aspects angle)
with sensor fuse, the fighter can use radar to measure range.

mrbsct wrote: I believe the PIRATE ISRT on the Tyhpoon can sense targets out to 90 km but can it use its Meteor to hit those targets?

For example if the IRST of the Tyhpoon sees a F22 or F35 at like around 80 km, and then ripple fires its entire Meteor load....do those missiles have a good chance of hitting?

90 km range is only if enemy fighter is at tail on aspects, maximum head on detection range of IRST again subsonic fighter is often around 30-40 km
And as explained before IRST and optical sensor have to zoom with very narrow FoV to achieve their maximum range,
for example :
OLS-27
A combined IRST/LR device for the Su-27, similar to the MiG-29's KOLS but more sophisticated, using a cooled, broader waveband, sensor. Tracking rate is over 25deg/sec. 50km range in pursuit engagement, 15km head-on. The laser rangefinder operates between 300-3000m for air targets, 300-5000m for ground targets.
Search limits are ±60deg azimuth, +60/-15° in elevation. Three different FOVs are used, 60° by 10°, 20° by 5°, and 3° by 3°. Detection range is up to 50km, whilst the laser ranger is effective from 300-3000m. Azimuth tracking is accurate to 5 secs, whilst range data is accurate to 3-10m. Targets are displayed on the same CRT display as the radar. Weighs 174kg.
OLS-27K for Su-33 featured new algorithms and better processor. It allegedly tracked targets in pursuit mode by their IR signature at 90 km during tests.

the maximum range are only achieved when 3° by 3° FoV are used.
So to answer your questions : yes these Meteor have good chances of hitting, but PIRATE detection range again fighter is more like 30-40 km rather than 80 km, and that is only in good weather conditions, if there is even a bit of cloud between Typhoon and F-35, F-22 then the IRST range shrink dramatically or even become useless

mrbsct wrote:The source wikipedia brought me to is the German Military website which said.


So can it find the F22 at 80 km? Maybye?

Firstly , according to the source :
The range of the system is between 50 and 80 kilometers, but could be up to 150 kilometers. The target identification can be carried out more than 40 kilometers. However, the weather conditions

So i would say in perfect weather condition the maximum range of PIRATE again fighter is 50 km head on , 80 km tail on , 150 km range is again things with very significant heat signature like Mig-25 , mig-31, SR-71 fly at mach 3 , 60K ft .The 150 km range may sound very significant , but it is for advertising purpose rather than real world use .As i stated before aas-42 have maximum range of 200 km , but it can detect something like an F-5 from only around 20 km .One can claim DAS have maximum 800 km range , but we all know the detection range again fighter is significantly shorter , like 20-25 km at best . . An example of maximum advertising range vs practical range of electric optical system :
Northrop AN/AXX-1 Television Camera System (TCS). TCS represents the TISEO/TCS family of stabilised TV telescopes, used by the USAF and USN on air defence and air superiority fighters. TCS provides sharp close-up images of hostile aircraft outside of visual range. Typical identification ranges quoted are. DC-10 at 85 miles, F-111 at 40 miles, C-130 at 35 miles and F-5 at 10 miles. TCS could be fitted to the F-18, though currently only the F-14A is equipped.

http://www.ausairpower.net/TE-EO-Systems.html
So you can see producer can easily claim AN/AXX-1 have range up too 85 miles or 140 km ,however in real world condition , again adversary such as F-5 , mig-21 , the range can shrink to less than 10 miles

According to Eurofighter pilot :
At a distance of about 50 km the Typhoon IRST (Infra-Red Search and Track) system could be capable to find even a stealthy plane “especially if it is large and hot, like the F-22″ as a Eurofighter pilot once said.

http://theaviationist.com/2013/02/21/ra ... yphoon-us/
so there you have it ,in head on position PIRATE can detect a supercruise F-22 from 50 km


mrbsct wrote:However I am not sure if it can track it effectively or find good identification ,range, position and velocity for its Meteor Salvo to be effective. How effective is the rangefinding, tracking system on the Tyhpoon?
Picard said that the Typhoon can still find the range by using by " PIRATE can carry out kinematic ranging (either through a weaving maneuver by a single fighter or datalinking several fighters together)." How true is this? This seems rather tedious
.
PIRATE doesnt have a LRF thus wont be able to measure range by conventional mean like other IRST .However in theory , PIRATE can measure range by using weaving( zig zag ) maneuver ( similar to what i mentioned earlier about how a RWR on fighter can passively measure range to another airborne target , same tactic , the only thing changed is the sensor ).
If you have several fighter , you can also datalink them and use triangulation to measure range , that is alot more simple , and if you triangulate for a long period of time , you will know the velocity of the enemy too.
Of course that is in theory , in reality , according to producer , PIRATE cant measure range


mrbsct wrote:The Tyhpoon website says:
Once a target has been tracked and identified PIRATE can be used to cue an appropriately equipped short range missile, i.e. a missile with a high off-boresight tracking capability such as ASRAAM. Additionally the data can be used to augment that of CAPTOR or off-board sensor information via the AIS. This should enable the Typhoon to overcome severe ECM environments and still engage its targets.

So at 50 km it can still use heat seekers like the ASRAAM without knowing the range,direction and velocity? However I doubt it would be effective because ASRAAM only travels Mach 3.

mrbsct they didnt say any where that PIRATE can be used to cue ASRAAM from 50 km distance , if target was at that distance it would make a lot more sense to use Meteor , since that missiles have much better kinematic , and it also have a data link .
The reason why they mentioned "short range missile, i.e. a missile with a high off-boresight tracking capability" is because , at shot range ( 15-20 km ) missiles dont have to fly in an arcs , they can fly a direct path and still reach target , range information wont be very necessary thus PIRATE can be used to cue missiles :D


mrbsct wrote:A duel between the Tyhpoon and the F22 in my estimates, the Tyhpoon will be instantly tracked by the F22 radar instantly around 260 km-200 km due to the RCS of the Typhoon being around 1m2 when weapons are loaded. The F22 is stealth, LPI and can use ALR-94 to make radar even more LPI so there is no way PraetorianDAS can jam or track it. While the Eurofighter outdated doppler radar can be easily tracked and jammed.

Eurofighter trance 3 will have CAPTOR-E MK2 , which is an AESA radar . Eurofighter can still jam F-22 radar by noise jamming , if it some how know F-22 is there ( by IRST or data link from ground VHF radar ). Of course F-22 can jam Eurofighter radar too , and it will be a lot more effective since F-22 have much smaller RCS , and more powerful radar
mrbsct wrote:The F22 plans the battle and gains a superior position such as above the Eurofighter out of the range of (PIRATE has only low azimuth when pointing up and F22 has higher flight ceiling)azimuth of the IRST. The Eurofighter has a superior missile the Meteor. No escape zones are around 25 km for the AIM-120B, and AIM-120C around 30 km(based on the report I found the that the improved AMRAAM in 2000 was supose to engage 9 g targets at 30 km, and Eurofighter pilots reporting they cannot escape 30 km F22 shots at Red Flag). AIM-120D is 50 percent increase range so around 45 km NEZ, 50 km if lucky and with the F22's superior kinetmatics to the F15's. The Meteor being three times the NEZ of AIM-120B is around 75 km NEZ.

NEZ is the distance where missiles will reach and over take target no matter what the aspect angle of it . It doesnt mean missiles will hit , it just mean the aircraft will have to defeat missiles by maneuver rather than turning and run away . NEZ depending alot on type of target , altitude ,missiles launching speed .
There is a very simple formula that can be used for estimating the performance of a missile. It goes like this :
Change in Velocity (Delta V) = 10 x Specific Impulse x LN (initial weight / final weight) m/s

This assumes that all the fuel is used to get the missile as fast as possible and
none is used to provide just enough thrust to sustain a given velocity.
In otherwords, it assumes an all-boost motor not a boost sustain motor.

For example, let'a take a look at the AIM-120A AMRAAM which we have some decent info on...

Launch weight = 335 lbs (Published stats)
Motor weight = 156 lbs (WPU-6/B HTPB rocket motor weight as per Raytheon)
Approximate specific impulse = 245 seconds (typical of HTPB solid motors)
Approximate fuel fraction of motor = 85% (typical of robust aluminum cased aerospace rocket motors)

OK... if 85% of the motor's mass is the fuel, we have about 132 lbs of fuel in the AMRAAM-A
-- roughly a 39.4% fuel fraction (sounds about right). So let's run the numbers...

Delta V = 10 x 245 x LN(335/(335-132)) = 1227 m/s

The formula predicts that the AMRAAM will go about 1227 m/s (~Mach 3.7) faster than it started.
If it is launched at say Mach 1.5 it'll be going Mach 5.2.
In reality the AMRAAM doesn't go that fast.
The reason is that not all the fuel is used to get it as fast as possible.
The AMRAAM's motor is a boost-sustain design.
It is probably grained to take the weapon to abut Mach 2.5~2.8 faster than it started at
(Mach 4+ in a typical Mach 1.5 release).
The rest of the fuel is shaped to burn much more slowly to keep it's velocity at
or near the achieved maximum out to a longer range before the motor burns out.


Well, for any given fuel fraction and specific impulse,
a designer can decide how fast he wants to go and how long he wants to stay at
or near the peak velocity achieved. For instance, if a missile carries 40% of its launch weight
as fuel and uses the typical a modern HTPB propellant motor, it can:-

(1) Spend 25% to get an approximate Mach 2.1 delta V and 15% on sustaining that speed for a relatively long while.
(2) Spend 30% to get an approximate Mach 2.7 delta V and 10% on sustaining that speed for a shorter while.
(3) Spend 40% to get an approximate Mach 3.8 delta V have no sustain burn time at all.

BTW, in reference to the above comment on deceleration... it doesn't really work that way.
If a missle starts at Mach 4 at burn out and decelerates 25% to Mach 3 after 10~15 seconds,
it WILL NOT decelerate to Mach 2 (another 33% from Mach 3) after 20~30 seconds.
This is impossible because aerodynamic drag (Fd = Cd x A x 0.5 x P x V^2) is a function of
the square of velocity.
As velocity decreases, drag force decreases exponentially in relation to it.
Hence, if the drag for at Mach 4 causes a 25% loss in velocity in 10~15 seconds,
there is no way a much lower drag force at Mach 3 will cause a 33% loss in velocity after
another 10~15 seconds.
What happens is that deceleration is non-linear;
you start off steep and the slope flattens out over time as velocity and hence drag drops.
It'll take a missile a heck of a lot longer to decelerate from Mach 4 to Mach 2 compared to
say Mach 2 to Mach 1 for instance.



Actually it also depends a heck of a lot on altitude (air density)...
Let's plug some numbers shall we?

Question: How much thrust is needed to sustain Mach 3.0 in an AAM like the AMRAAM?

Drag force (Newtons) = 0.5 x P x V^2 x Cd x A

P = Density of Air (kg/m^3) ; ~1.29 kg/m^3 @ sea level; ~0.232 kg/m^3 @ 12,000 m
V = Velocity (m/s) ; Mach 1 = 340 m/s @ sea level; ~295 m/s @ 12,000 m
Cd = Co-efficient of Drag ; ~ 0.6 to 0.95 for rockets depending mostly on finnage,
nose and tail profile
A = Sectional Area (m^2) ; ~ 0.025 m^2 for a 7" diameter missile.

For an AMRAAM like AAM going at high altitudes (40,000 ft)...

Drag Force @ Mach 3 = 0.5 x 0.232 x (295x3)^2 x 0.70 x 0.025 = 1590 Newtons = 357 lbs
Drag Force @ Mach 2 = 0.5 x 0.232 x (295x2)^2 x 0.70 x 0.025 = 707 Newtons = 159 lbs
Drag Force @ Mach 1 = 0.5 x 0.232 x 295^2 x 0.70 x 0.025 = 177 Newtons = 39.8 lbs

The same missile going Mach 3 at Sea Level...

Drag Force @ Mach 3 = 0.5 x 1.29 x (340x3)^2 x 0.70 x 0.025 = 11,744 Newtons = 2640 lbs
Drag Force @ Mach 2 = 0.5 x 1.29 x (340x2)^2 x 0.70 x 0.025 = 5,219 Newtons = 1173 lbs
Drag Force @ Mach 1 = 0.5 x 1.29 x 340^2 x 0.70 x 0.025 = 1,305 Newtons = 293 lbs

Assuming that there is no sustainer,
the deceleration experienced at Mach 3 by the 203 lbs (empty) missile is

Deceleration @ Mach 3 = -F / mass = -1590 / (203 x 0.454) = -17.3 m/s^2 = - Mach 0.059/sec @ 40,000 ft
Deceleration @ Mach 2 = -F / mass = -707 / (203 x 0.454) = -7.67 m/s^2 = - Mach 0.026/sec @ 40,000 ft
Deceleration @ Mach 1 = -F / mass = -177 / (203 x 0.454) = -1.92 m/s^2 = - Mach 0.0065/sec @ 40,000 ft

Deceleration @ Mach 3 = -F / mass = -11744 / (203 x 0.454) = -127 m/s^2 = - Mach 0.39/sec @ sea level
Deceleration @ Mach 2 = -F / mass = -5219 / (203 x 0.454) = -56.6 m/s^2 = - Mach 0.17/sec @ sea level
Deceleration @ Mach 1 = -F / mass = -1305 / (203 x 0.454) = -14.2 m/s^2 = - Mach 0.042/sec @ sea level

OK... enough of the math and the formulas... what does all these mean?
Well, it means that while coasting at Mach 3 an AAM is going to lose about less than 2% of
its velocity a second at high altitudes while it stands to lose about 13% of its velocity at
sea level! Huge difference isn't it?
Remember though that the rate of deceleration actually DECREASES as the
missile's velocity decreases.
It is easy to see that one can claim that a missile can burn out burn out its booster
and sustainer and be effective out to over 100 km at high altitudes or be useful only
against helos after 10km on the deck!

Also, we can make a pretty educated guess as to how much thrust the sustainer has to make.
An AMRAAM class missile with a 400 lbs sustain thrust will be able to stay
above Mach 3 at high altitudes and stay about Mach 1.2 at sea level.
An AMRAAM class missile carrying about 10% of its launch weight as sustainer
grained propellant will be able to keep this level of thrust lit for 20.5 seconds
in addition to whatever the boost time was using the 30% of its fuel to get a
roughly Mach 2.7 Delta V after launch.
A missile like this when fired at Mach 1.5 will reach Mach 4+ and keep
above Mach 3 for the duration of the sustainer at high altitudes.
It will also reach about Mach 2.5 and keep above about Mach 1.2 at sea level.
A motor grained for this thrust profile can have a 10 second boost at ~ 2460 lbs thrust and
a 20 second sustain burn at 400 lbs thrust -- this is a 5:1 boost sustain ratio.
This is also about right for thrust profiles of star grain vs
core burn solid propellant burn rate profiles.




Another rough rule of thumb:-

The time it takes for a missile to lose 25% of its velocity after burn out at supersonic speeds.

Never @ > 100,000 m (~300,000 ft) ; in space
~150 seconds @ 24,000 m (~80,000 ft)
~70 seconds @ 18,000 m (~ 60,000 ft)
~25 seconds @ 12,000 m (~ 40,000 ft)
~10 seconds @ 6,000 ft (~20,000 ft)
~5 seconds @ Sea Level

Remember, fractions over time are not additive.
In otherwords, if a missile loses about 25% of its velocity in 10 seconds,
in the 10 subsequent seconds (t =20s) the missile loses approximately another 25% of
the remaining 75% not a 100%. Total velocity loss is ~43.75% not 50%.

This is highly collated to the fall in air density.
Drag = 0.5 x P x V^2 x Cd x A.
Holding everything else constant Drag falls proportionally to density.
Drag also falls exponentially with Velocity which accounts for the loss in velocity
in the given time slices being about 25% instead of closer to 40%.
So based on the formula above you can estimated NEZ for yourself .


mrbsct wrote:In close range WVR, chances are lessened since Eurofighter has HMD and ASRAAM is better than AIM-9x

I dont think ASRAAM is better than AIM-9x , but sure in WVR , Eurofighter will have the upper hand because F-22 lack HMD
mrbsct wrote:If Eurofighter fought the F35, the F35's higher IR signature(lack of IR reducing nozzle and no supercruise)will put it at a disadvantage

I cannot find any reason why F-35 would have bigger IR signature than Eurofighter , or F-22 . No supercruise mean it fly slower thus have smaller skin friction => smaller heat signature . F-35 operate at lower altitude compared to F-22 , Eurofighter thus less contrast in heat signature with background and there are more moisture to absorb IR radiation . F-35 have IR reducing nozzle too ( it called LOAN nozzle ) , both F-22 and F-35 have a paint called Topcoat to reduce IR signature .
mrbsct wrote:plus it can carry only 4 AMRAAMs. Since its RCS is lower the CAPTOR can probably find it at 40-50 km unless the F35 decides to jam it.

CAPTOR (EF-2000 Tranch 1 and 2)

For RCS 0.0001 m2 class target: 12 km+
For RCS 0.001 m2 class target: 22 km+
For RCS 0.1 m2 class target: 70 km+
For RCS 1.0 m2 class target: 124 km+
For RCS 5.0 m2 class target: 185 km+
For RCS 10.0 m2 class target: 220 km+
CAPTOR-E will do better since it is an AESA radar , however , CAPTOR-E still smaller than APG-81 , APG-77 , and F-22/ F-35 were designed to penetrate S-300/400 defense , so i dont think there is any change for Eurofighter to detect them first by radar . Why wouldn't the F-35 pilot jam Eurofighter radar though ? :?
Btw According to recent interviewed F-35 have even lower RCS than F-22 .
mrbsct wrote:Also the F35 has bad kinematics so its NEZ is much lower than 45 km with the AIM-120D.

both Eurofighter and F-35 can carry Meteor .About NEZ , refer to the formula above
mrbsct wrote:If it came down to WVR, the Eurofighter has better manuerablity and the F35 can't carry the AIM-9x stealthily. The Eurofighter has a huge advantage over the F35 in WVR and BVR IMO. ]

F-35 have DAS and DIRCM , Eurofighter doesn't .And no Eurofighter doesnt have advantage over any stealth fighter in BVR

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 18:32
by eloise
Picard and Wikipedia did claim PIRATE range of 100 km again subsonic fighter head on, however, there isn't any official source that support that assessment, so obviously that just one of many BS claim that he made
The producer of PIRATE however claim that it have maximum range of 145 km in perfect conditions , that may sound very high, however without knowing that type of target, altitude and aspect, that mean nothing, even Aas-42 have maximum range of 200 km

P/s : also, PIRATE actually lack LFR, unlike OFS, EOTS or OLS-35 :? , this actually a surprise for me, so Typhoon still have to rely on it's radar to lock target

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 19:00
by eloise
neurotech wrote:
Also note that the F-35 has two different systems. EOTS and EODAS. The EOTS has a 40+ mile range against a fighter aircraft. The targeting pods on the F-16 are an earlier version. The EODAS doesn't have the same resolution at long range, but has 360 degree scan, and can point the EOTS at the target. The two systems are fused together to provide maximum situational awareness, even with low RCS targets and jammers.

IMO
Since DAS range is alot shorter than EOTS, because it have much wider FoV compared to EOTS in maximum zoom , it is likely that EOTS will be cued by APG-81 and ASQ-239 rather than DAS. DAS may still cue EOTS at short range though

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 21:06
by mrbsct
The source wikipedia brought me to is the German Military website which said.

The range of the system is between 50 and 80 kilometers, but could be up to 150 kilometers. The target identification can be carried out more than 40 kilometers. However, the weather conditions

So can it find the F22 at 80 km? Maybye? However I am not sure if it can track it effectively or find good identification ,range, position and velocity for its Meteor Salvo to be effective. How effective is the rangefinding, tracking system on the Tyhpoon?

So the target identification is around 40-50 km depending on the wealthier conditions in my predictions. Picard said that the Typhoon can still find the range by using by " PIRATE can carry out kinematic ranging (either through a weaving maneuver by a single fighter or datalinking several fighters together)." How true is this? This seems rather tedious.

The Tyhpoon website says:
Once a target has been tracked and identified PIRATE can be used to cue an appropriately equipped short range missile, i.e. a missile with a high off-boresight tracking capability such as ASRAAM. Additionally the data can be used to augment that of CAPTOR or off-board sensor information via the AIS. This should enable the Typhoon to overcome severe ECM environments and still engage its targets.

So at 50 km it can still use heat seekers like the ASRAAM without knowing the range,direction and velocity? However I doubt it would be effective because ASRAAM only travels Mach 3.

A duel between the Tyhpoon and the F22 in my estimates, the Tyhpoon will be instantly tracked by the F22 radar instantly around 260 km-200 km due to the RCS of the Typhoon being around 1m2 when weapons are loaded. The F22 is stealth, LPI and can use ALR-94 to make radar even more LPI so there is no way PraetorianDAS can jam or track it. While the Eurofighter outdated doppler radar can be easily tracked and jammed.

The F22 plans the battle and gains a superior position such as above the Eurofighter out of the range of (PIRATE has only low azimuth when pointing up and F22 has higher flight ceiling)azimuth of the IRST. The Eurofighter has a superior missile the Meteor. No escape zones are around 25 km for the AIM-120B, and AIM-120C around 30 km(based on the report I found the that the improved AMRAAM in 2000 was supose to engage 9 g targets at 30 km, and Eurofighter pilots reporting they cannot escape 30 km F22 shots at Red Flag). AIM-120D is 50 percent increase range so around 45 km NEZ, 50 km if lucky and with the F22's superior kinetmatics to the F15's. The Meteor being three times the NEZ of AIM-120B is around 75 km NEZ.

So with the AIM-120D the F22 can beat the Eurofighter with superior positioning. But with the AIM-120C chances are lessened since IRST can find that range and its WVR. The F22 can fire at 50 km, to screw up the Typhoon's postioning to gain the upper hand at 30-40 km. In close range WVR, chances are lessened since Eurofighter has HMD and ASRAAM is better than AIM-9x.

If Eurofighter fought the F35, the F35's higher IR signature(lack of IR reducing nozzle and no supercruise)will put it at a disadvantage, plus it can carry only 4 AMRAAMs. Since its RCS is lower the CAPTOR can probably find it at 40-50 km unless the F35 decides to jam it. Also the F35 has bad kinematics so its NEZ is much lower than 45 km with the AIM-120D. If it came down to WVR, the Eurofighter has better manuerablity and the F35 can't carry the AIM-9x stealthily. The Eurofighter has a huge advantage over the F35 in WVR and BVR IMO.

Do you agree?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 29 May 2015, 22:16
by mrigdon
mrbsct wrote:If Eurofighter fought the F35, the F35's higher IR signature(lack of IR reducing nozzle and no supercruise)will put it at a disadvantage, plus it can carry only 4 AMRAAMs.


The F-35 does have an IR reducing nozzle, it's just a different design that what was used in the F-22. And the F-35 may be capable of supercruise, depending on loadout. There's quite a bit that hasn't been publicly released about the plane, although it's publicly debated to no end.

There's another thread concerning the RCS of the F-35 with Sidewinders mounted on the far pylons. It's possible that the F-35 can carry 4 AMRAAMs and 2 Sidewinders without significant RCS penalty, so that would get an F-35 closer to the air-to-air loadout of a Raptor.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 30 May 2015, 00:33
by Scorpion1alpha
Let's get off the F-35 discussion here. This topic isn't about the F-35, isn't the F-35 forum nor do I care about the F-35 in this forum. Future F-35 stuff mention here will be deleted.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 30 May 2015, 06:20
by eloise
Scorpion1alpha wrote:Let's get off the F-35 discussion here. This topic isn't about the F-35, isn't the F-35 forum nor do I care about the F-35 in this forum. Future F-35 stuff mention here will be deleted.

come on, why delete everything :( took me quite long to write that post :|

Re: F22 vs. IRST and radar jammers

Unread postPosted: 30 May 2015, 09:23
by Scorpion1alpha
eloise wrote:
Scorpion1alpha wrote:Let's get off the F-35 discussion here. This topic isn't about the F-35, isn't the F-35 forum nor do I care about the F-35 in this forum. Future F-35 stuff mention here will be deleted.

come on, why delete everything :( took me quite long to write that post :|

Apparently, you're not getting it. I'm also not going to repeat myself. If you do it again, it's going to happen again.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 14 Jul 2015, 18:59
by nicktheaircraftexpert
hornetfinn wrote:For example OLS-35 in Su-35 is still nowhere as good as AN/AAS-42 produced for F-14D over 20 years ago.


You need to prove that

Re: F22 vs. IRST and radar jammers

Unread postPosted: 14 Jul 2015, 19:07
by eloise
nicktheaircraftexpert wrote:
hornetfinn wrote:For example OLS-35 in Su-35 is still nowhere as good as AN/AAS-42 produced for F-14D over 20 years ago.


You need to prove that

range

Re: F22 vs. IRST and radar jammers

Unread postPosted: 17 Jul 2015, 06:08
by nicktheaircraftexpert
mrbsct wrote:The source wikipedia brought me to is the German Military website which said.

The range of the system is between 50 and 80 kilometers, but could be up to 150 kilometers. The target identification can be carried out more than 40 kilometers. However, the weather conditions

So can it find the F22 at 80 km? Maybye? However I am not sure if it can track it effectively or find good identification ,range, position and velocity for its Meteor Salvo to be effective. How effective is the rangefinding, tracking system on the Tyhpoon?

So the target identification is around 40-50 km depending on the wealthier conditions in my predictions. Picard said that the Typhoon can still find the range by using by " PIRATE can carry out kinematic ranging (either through a weaving maneuver by a single fighter or datalinking several fighters together)." How true is this? This seems rather tedious.

The Tyhpoon website says:
Once a target has been tracked and identified PIRATE can be used to cue an appropriately equipped short range missile, i.e. a missile with a high off-boresight tracking capability such as ASRAAM. Additionally the data can be used to augment that of CAPTOR or off-board sensor information via the AIS. This should enable the Typhoon to overcome severe ECM environments and still engage its targets.

So at 50 km it can still use heat seekers like the ASRAAM without knowing the range,direction and velocity? However I doubt it would be effective because ASRAAM only travels Mach 3.

A duel between the Tyhpoon and the F22 in my estimates, the Tyhpoon will be instantly tracked by the F22 radar instantly around 260 km-200 km due to the RCS of the Typhoon being around 1m2 when weapons are loaded. The F22 is stealth, LPI and can use ALR-94 to make radar even more LPI so there is no way PraetorianDAS can jam or track it. While the Eurofighter outdated doppler radar can be easily tracked and jammed.

The F22 plans the battle and gains a superior position such as above the Eurofighter out of the range of (PIRATE has only low azimuth when pointing up and F22 has higher flight ceiling)azimuth of the IRST. The Eurofighter has a superior missile the Meteor. No escape zones are around 25 km for the AIM-120B, and AIM-120C around 30 km(based on the report I found the that the improved AMRAAM in 2000 was supose to engage 9 g targets at 30 km, and Eurofighter pilots reporting they cannot escape 30 km F22 shots at Red Flag). AIM-120D is 50 percent increase range so around 45 km NEZ, 50 km if lucky and with the F22's superior kinetmatics to the F15's. The Meteor being three times the NEZ of AIM-120B is around 75 km NEZ.

So with the AIM-120D the F22 can beat the Eurofighter with superior positioning. But with the AIM-120C chances are lessened since IRST can find that range and its WVR. The F22 can fire at 50 km, to screw up the Typhoon's postioning to gain the upper hand at 30-40 km. In close range WVR, chances are lessened since Eurofighter has HMD and ASRAAM is better than AIM-9x.

If Eurofighter fought the F35, the F35's higher IR signature(lack of IR reducing nozzle and no supercruise)will put it at a disadvantage, plus it can carry only 4 AMRAAMs. Since its RCS is lower the CAPTOR can probably find it at 40-50 km unless the F35 decides to jam it. Also the F35 has bad kinematics so its NEZ is much lower than 45 km with the AIM-120D. If it came down to WVR, the Eurofighter has better manuerablity and the F35 can't carry the AIM-9x stealthily. The Eurofighter has a huge advantage over the F35 in WVR and BVR IMO.

Do you agree?



The PIRATE is a QWIP so it gets less affected by weather conditions

Re: F22 vs. IRST and radar jammers

Unread postPosted: 17 Jul 2015, 06:43
by eloise
nicktheaircraftexpert wrote:
The PIRATE is a QWIP so it gets less affected by weather conditions

No

Re: F22 vs. IRST and radar jammers

Unread postPosted: 18 Jul 2015, 21:46
by disconnectedradical
nicktheaircraftexpert wrote:The PIRATE is a QWIP so it gets less affected by weather conditions


What kind of weather? Fog? Haze? Smoke? The best frequency for penetrating haze is actually short wave IR, while mid wave IR is better for seeing through humidity. I believe PIRATE is dual band with both mid wave and long wave IR frequencies. QWIP does little in this regard other than potentially increasing the number of bands employed. With long wave the ambient emissions from ground objects becomes much more pronounced.

What is your source stating the PIRATE uses QWIP anyways?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 19 Jul 2015, 03:12
by nicktheaircraftexpert
disconnectedradical wrote:
nicktheaircraftexpert wrote:The PIRATE is a QWIP so it gets less affected by weather conditions


What kind of weather? Fog? Haze? Smoke? The best frequency for penetrating haze is actually short wave IR, while mid wave IR is better for seeing through humidity. I believe PIRATE is dual band with both mid wave and long wave IR frequencies. QWIP does little in this regard other than potentially increasing the number of bands employed. With long wave the ambient emissions from ground objects becomes much more pronounced.

What is your source stating the PIRATE uses QWIP anyways?


there are a bunch of sources if u want to you can look them up

Re: F22 vs. IRST and radar jammers

Unread postPosted: 04 Dec 2015, 23:16
by house_13
eloise wrote:Due to the principles that they work, deceptive jamming are quite useless against AESA radar

The deceptive jammer received enemy incoming RF signal , it analyse , and then re transmitted that signal with different characteristic , like different doppler , pulse width . In contrast to noise jamming, deception jammer tries to mimic the radar echo so that the radar will respond as if it is receiving an echo from another aircraft or ship.


So deceptive jamming have to receive and process signal before they can send out jamming signal
Here are some characteristics of AESA radar that make them very resistance to jamming : frequency agility , and random PFR , random scan pattern
Jamming is likewise much more difficult against an AESA. Traditionally, jammers have operated by determining the operating frequency of the radar and then broadcasting a signal on it to confuse the receiver as to which is the "real" pulse and which is the jammer's. This technique works as long as the radar system cannot easily change its operating frequency. When the transmitters were based on klystron tubes this was generally true, and radars, especially airborne ones, had only a few frequencies to choose among. A jammer could listen to those possible frequencies and select the one to be used to jam.
Most radars using modern electronics are capable of changing their operating frequency with every pulse. An AESA has the additional capability of spreading its frequencies across a wide band even in a single pulse, which equates to lowering the emission power, making jammers much less effective. Although it is possible to send out broadband white noise against all the possible frequencies, this means the amount of energy being sent at any one frequency is much lower, reducing its effectiveness

http://self.gutenberg.org/articles/aesa_radar


In general, high PRF radars are more resistant to ECM because their average power is greater. Changing the PRF in a random fashion is an effective counter to deception because deception ECM depends on predictability of the radar. However, because PRF is related to the basic timing of the radar, this technique results in additional complexity and expense. Random PRF has been employed as a very effective ECCM feature in some radars for many years and has the additional benefit of elimination of MTI radar blind speeds.

Scan pattern. The radar scan pattern can influence ECCM capability because it influences the amount of energy directed toward the radar target. An active tracking phased-array radar is quite ECM resistant because of its ability to rapidly scan its radar beam in a random fashion than in the regular circular or sector scan pattern of conventional radars. This irregular beam positioning would give the opposing ECM system little or no warning and make it impossible to predict where and when to transmit false signals. In systems where scanning is performed in the receiver rather than in the transmitted beam, such as those mentioned in the section on angle deception, ECM has no direct access to the radar scan pattern and thus has difficulty using that information to interfere with the radar system operation.

Frequency. Frequency agility is a significant ECCM design feature. Using components such as frequency synthesizers (something like those employed in radio scanners) instead of conventional crystal-controlled oscillators, some radars are able to change frequency within one pulse repetition time (PRT). This makes deception and jamming very difficult. The radar can be designed to change frequency automatically within a certain range, or this can be done manually.

http://fas.org/man/dod-101/navy/docs/fun/part11.htm

To effectively jam an AESA radar, you would need to use noise jamming. For a noise jammer to be effective , the signal to noise ratio that enemy received must be less than 1. To achieve that you either have to increase your jamming power or reduce your reflected signal , or both. F-35 use APG-81 to jam, AESA have very narrow beam, as a result jamming power are more focused at enemy's place. It's also have a tiny RCS, thus reducing the reflected signal significantly
Even if we assume both side use the same kind of jammer, it still much easier for a stealth fighter to jam a normal fighter's radar than the other way round. Here is why :

Image
not only that lower RCS reduce burn through distance , jamming power required will decrease in the same rate as RCS reduction ,50% reduction in RCS = 50% less power required to overwhelm real radar reflection with noise ( you can work it out for yourself , 99.9% reduction in RCS= 99.9% less power required to achieve same level of effectiveness , and so on )
now let take example of 4 aircraft :
1) B-52 : RCS = 100 m2
2) Mig-31 : RCS = 10 m2
3) Mig-35 : RCS = 1 m2
4) F-35 : RCS = 0.001 m2
now compared them :
from B-52 to F-35 then RCS is reduced by 99.999% =>99.999% less power require
from Mig-31 to F-35 then RCS is reduced by 99.99%=>99.99% less power require
from Mig-35 to F-35 then RCS is reduced by 99.9% =>99.9% less power require
( if you not good at math then use this http://www.percentagecalculator.net/ the lowest row )

so again a very powerful enemy radar : if F-35 need 5 kW jammer to shield it's radar reflection with noise signals then Mig-35 will need a 5 MW jammer , Mig-31 will need 50 MW jammer , B-52 will required 500 MW jammer , you can argue that bigger aircraft can carry more powerful jammer but remember even the SPY-1 only have power of 5 MW


What about rafale shooting passively a target at a distance far more than 10 nm at six o'clock as said by a test pilot?

What about using interferometry technique by RWR to allow precise ranging for firing solution?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 05 Dec 2015, 04:01
by eloise
house_13 wrote:
What about rafale shooting passively a target at a distance far more than 10 nm at six o'clock as said by a test pilot?

there wasnt any actual shot , it was a simulated shot
and only at distance of 7.8nm ( not even 10 nm let alone further than that)
Image


if you look careful at my picture, they mentioned a method to estimate range again known emitter ( when you already know exactly the kind of radar that enemy have ) hence it will only work again stable emitter ( old mechanical radar ) whose frequency and pulse repetition interval (PRI) remain relatively constant from pulse to pulse. a
Image

house_13 wrote: What about using interferometry technique by RWR to allow precise ranging for firing solution?

you have some misunderstanding here
Interferometer are what used to determine the direction of the emitter , from that you can use the technique i listed to determine the distance to target . But interferometry is not something that determine range on it's own
Image
1028882527.png

Re: F22 vs. IRST and radar jammers

Unread postPosted: 05 Dec 2015, 04:11
by eloise
One of the best ESM system today is the ALQ-218 on EA-18G
it use both long and short baseline interferometer, but still can only geolocate ground emitter
The AN/ALQ-218 utilizes a unique combination of short and long baseline interferometer techniques along with a patented passive ranging algorithmto provide precisionGeolocation of all ground-based emitters

http://www.northropgrumman.com/Capabili ... fault.aspx

Re: F22 vs. IRST and radar jammers

Unread postPosted: 05 Dec 2015, 17:30
by house_13
there wasnt any actual shot , it was a simulated shot
and only at distance of 7.8nm ( not even 10 nm let alone further than that)


But if you can do it at distance of 7.8 nm , you can do it further than that using the same method
the picture doesn't mean that this is its max range

if you look careful at my picture, they mentioned a method to estimate range again known emitter ( when you already know exactly the kind of radar that enemy have ) hence it will only work again stable emitter ( old mechanical radar ) whose frequency and pulse repetition interval (PRI) remain relatively constant from pulse to pulse.


Those methods are more effective against ground targets than fighters

Interferometer are what used to determine the direction of the emitter , from that you can use the technique i listed to determine the distance to target . But interferometry is not something that determine range on it's own


In THALES official site they say :
Using sophisticated techniques, such as interferometry for high precision DOA and passive ranging,

https://www.thalesgroup.com/en/worldwid ... ce/spectra

I can give you many links that say interferometry used for accurate measuring of distance , for example
A state-of-the-art interferometer can measure distances to within 1 nanometer

http://www.explainthatstuff.com/howinte ... swork.html

Re: F22 vs. IRST and radar jammers

Unread postPosted: 05 Dec 2015, 18:21
by eloise
house_13 wrote:But if you can do it at distance of 7.8 nm , you can do it further than that using the same method

Actually no , it much much easier to measure range at short distance because it easier for triangulation ( function of range and angle ) and also the rate of change are very high at short range allow easier measurement
house_13 wrote:the picture doesnt mean that this is its max range

No evidence that it possible at much longer distance like BVR

house_13 wrote:those methods are more effective against ground targets than fighters

actually estimate range by measure radiated power of a stable emitter is probably the only method that would be practical again moving air target

house_13 wrote:in THALES official site they say :
Using sophisticated techniques, such as interferometry for high precision DOA and passive ranging

https://www.thalesgroup.com/en/worldwid ... ce/spectra


:doh: come on ,pay attention to what you post
and passive ranging again ground emitter is much much easier than a moving air target ( i already explained the reason why )

house_13 wrote:I can give u many links that say interferometry used for accurate measuring of distance , for example
A state-of-the-art interferometer can measure distances to within 1 nanometer

http://www.explainthatstuff.com/howinte ... swork.html

it really doesn't matter how many links you give if you don't really understand what they talking about
have a look https://str.llnl.gov/str/Sommargren.html
there a certain reason why interferometer can measure distance very accurately in specific case
you need to understand the working principles first

Re: F22 vs. IRST and radar jammers

Unread postPosted: 31 Jan 2016, 15:45
by indochina
AN/ALQ-184 just power is 9.1 kVa = kW ? You can not know the power factor, how you can conclude ECM pod with 5 KW power can reduce RCS 50%?

http://home.tiscali.cz/falcon4/downloads/alq184.pdf

No ECM pod is yet strong enough to reduce 50% of RCS.

F-35 AESA radar jamming is just advertising, it has never been tested. You know the peak power of the APG-81 ? :bang:

Irbis-E has peak power rating of 20 kilowatts, even APG-77 can not jammer it, because APG-77 peak power is 12 Kw.
According to one of evaluation, the APG-81 has a capacity of only 2 KW

http://en.airforceworld.com/a/20150513/8_2.html

The radar just scan into the fuselage frame, it is detected by the RCS, RCS is what you do not understand, which is reflected signals of the fuselage to the radar detect-track

Image

Image

Image

Image

Re: F22 vs. IRST and radar jammers

Unread postPosted: 31 Jan 2016, 20:13
by SpudmanWP
indochina wrote: F-35 AESA radar jamming is just advertising, it has never been tested.

I'm not sure what you mean as the APG-81's EW capabilities have been demonstrated in flight tests and at Northern Edge for years.

2011 http://www.af.mil/News/ArticleDisplay/t ... -2011.aspx

2015 http://www..mil/news/docs/20150624_FighterTest.pdf

Irbis-E has peak power rating of 20 kilowatts, even APG-77 can not jammer it, because APG-77 peak power is 12 Kw.
According to one of evaluation, the APG-81 has a capacity of only 2 KW

http://en.airforceworld.com/a/20150513/8_2.html


An AESA jammer has several advantages, not the least of which is that it's signals only have to go half the distance of the radar's, so you cannot compare them 1:1.

Also, you read that link wrong. Here is the direct quote on the APG-81's "estimated" power.

Due to the small size of the nose of the craft, the APG-81 radar has less components than the APG-77, although there is currently no concrete figure, it is likely around 1,200, giving it peak power of 12 kW and average power of around 2 kW.


So, according to his estimation the APG-81 has a peak power rating of 12kW, not 2kW (that was the "average" power, not "peak"). I noticed that you did not quote his APG-77 peak power estimate that was 22kW.

He was wrong in one fact (not his fault as this was widely believed at the time), the APG-81 has over 1600 T&R modules, not ~1200. Using his power ratios that puts the APG-81 at 16kw peak power, not 12kw. Thanks to it being AESA based, it can also be focused into a tighter beam thereby increasing it's effectiveness-to-kW ratio.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 07:48
by eloise
indochina wrote:AN/ALQ-184 just power is 9.1 kVa = kW ? You can not know the power factor, how you can conclude ECM pod with 5 KW power can reduce RCS 50%?

No ECM pod yet strong enough to reduce 50% of RCS.

No one say ECM reduce RCS , i said the lower the RCS is , the easier it wold be to jam adversary radar , and no it isn't speculation , it is basic physic , you cant even write simple English phrase so I don't expect you to understand it anyway

indochina wrote:F-35 AESA radar jamming is just advertising, it has never been tested. :

Yes it was tested

indochina wrote: Irbis-E has peak power rating of 20 kilowatts, even APG-77 can not jammer it, because APG-77 peak power is 12 Kw.
According to one of evaluation, the APG-81 has a capacity of only 2 KW

Whether it can jam or not depending on the reflection signal , peak power is irrelevance here

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 07:58
by hornetfinn
Indochina, you are either totally uninformed or saddest troll attempt I've seen.

You really think that peak power is the only thing that matters between radar and jammer systems? Then all the jammer systems in existence are worthless and all the air forces have spent their money for nothing. Even the most powerful jammers would then be able to jam only the least powerful radars as there are not many jammers that can transmit with tens of kilowatts of power, let alone Megawatts many larger radars can.

I love how you demand official links or reliable sources but you only present totally worthless links with no real or reliable information. Why don't you do as you demand from others?

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 08:35
by eloise
hornetfinn wrote:Indochina, you are either totally uninformed or saddest troll attempt I've seen.

You really think that peak power is the only thing that matters between radar and jammer systems? Then all the jammer systems in existence are worthless and all the air forces have spent their money for nothing. Even the most powerful jammers would then be able to jam only the least powerful radars as there are not many jammers that can transmit with tens of kilowatts of power, let alone Megawatts many larger radars can.


It fking hilarious that everyone over keypub told him exactly the same things as i did but he so blinded by his agenda that he thought they agreed with him :doh:

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 16:34
by les_paul59
Probably very unlikely that the F22 and SU35s come in contact w/ each other in syria but look who just showed up to the party
https://www.the-newshub.com/internation ... s-to-syria

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 17:16
by SpudmanWP
indochina wrote:Test jammer the public radar?
What does that even mean???

I only see text generalities are not specifically mentioned. It does not say that the APG-81 jamming the FCR of F-15C or AIM-120 radar head seeker
I'll have to find the quote, but the APG-81 has been stated to have jammed the APG-77.

22Kw but you can not maintain continuous power. You can demonstrate APG-77 can maintain the energy of 22 Kw continuous? any concrete evidence! official link or reliable source !
Can the IRBIS-E maintain a continuous 20kw? I clearly stated the F-22's 22kW was it's "peak" power rating estimate.

My issue with your quote was that you equated the "peak" power of the IRBIS-E to the estimated "average" power of the APG-81 without stating the difference.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 18:42
by eloise
SpudmanWP wrote:Can the IRBIS-E maintain a continuous 20kw? I clearly stated the F-22's 22kW was it's "peak" power rating estimate.

My issue with your quote was that you equated the "peak" power of the IRBIS-E to the estimated "average" power of the APG-81 without stating the difference.

He cannot even distinguish between strength of skin reflection, radar pulse and radar peak power , so how can you expect him to know the different between peak and average power of radar :slap:
That guys is joke really, his nationalistic agenda blind him so bad that he refuses to believe anything good come from USA.He don't want to learn new things. What he want is for others to "confirm" his belief

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 20:51
by garrya
eloise wrote:It fking hilarious that everyone over keypub told him exactly the same things as i did but he so blinded by his agenda that he thought they agreed with him :doh:

From his comments on Keypublishing, to me it seem like he believes that "active cancellation" and " connection between radar cross section, and J/S ratio" are the same thing.

Re: F22 vs. IRST and radar jammers

Unread postPosted: 01 Feb 2016, 20:57
by eloise
garrya wrote:From his comments on Keypublishing, to me it seem like he believes that "active cancellation" and " connection between radar cross section, and J/S ratio" are the same thing.

Spot on, that why he so quickly agree with anyone who said active cancellation isnot possible because that support his agenda , little does he know that ''active cancellation'' is a completely different thing from " lower RCS make jamming more effective " :mrgreen: . It best to just ignore him , he doesnt really have any intellectual argument or critical thinking , there is no way to reason with that guy ,even when he know he is completely wrong he just keep screaming until you are bored so that he can declare himself the winner ( typical Russia Stronk troll, similar to JSR :wink: ) .