This is a discussion on A simple method to engage stealthy target within the Air Force & Aviation forum, part of the Global Defense & Military category; Airplane stealth technology poses a serious challenge to radar detection and missile guidance. But no airplane is invisible to infrared ...
Airplane stealth technology poses a serious challenge to radar detection and missile guidance. But no airplane is invisible to infrared seeker, no matter it's a F-22 or B-2. As long as the friction between moving air and solid surface exists, a sensitive infrared seeker can always detect the thermal difference. The IRST on Su-27 can track a F-22 like target more than 15 miles away. And modern infrared imaging seeker will make any counter-measurement useless. So an AIM-9X can always secure a hit on a F-22 within its range.
Old style radars use very long wavelength. It can detect stealth targets but unable to guide a conventional missile accurately due to its poor resolution(up to a few miles' error). If we combine a medium-range surface/air-to-air missile and an infrared seeker, something like an R-27ET, then it's a stealth target killer. Using datalink or radio command to guide such a missile to the approximate airspace near an F-22, the infrared seeker will finish the rest.
This is a simple method based on existing technology to defeat the stealth aircraft or cruise missiles. Previously people did propose using such a radar to guide fighters to get close to an F-22. Now using such radar to guide long range IR missiles to get close to an F-22 is more meaningful.
Airplane stealth technology poses a serious challenge to radar detection and missile guidance. But no airplane is invisible to infrared seeker, no matter it's a F-22 or B-2. As long as the friction between moving air and solid surface exists, a sensitive infrared seeker can always detect the thermal difference. Some seekers have an effective range up to 20 miles. And modern infrared imaging seeker will make any counter-measurement useless. So an AIM-9X can always shoot down a F-22 in its range.
Old style radars use very long wavelength. It can detect stealthy targets but with very poor resolution(up to a few miles' error). It cannot guide any conventional missile accurately. But If we combine a medium-range surface/air-to-air missile and an infrared seeker, something like an R-27ET, then it's a stealthy target killer. Using datalink or radio command to guide such a missile to the approximate space near an F-22, the infrared seeker will finish the rest.
Low observability isn't just about radar, aircraft like the F-22 and F-35 make significant use of IR reduction methods as well. This quote is taken from an RAAF officer who has flown against the F-22 at Red Flag:
"I can't see the [expletive deleted] thing," said RAAF Squadron Leader Stephen Chappell, exchange F-15 pilot in the 65th Aggressor Squadron. "It won't let me put a weapons system on it, even when I can see it visually through the canopy. [Flying against the F-22] annoys the hell out of me."
Now, given IR seeker technology is the dominant form of guidance among short range missiles all over the world, it follows that low observability platforms designed with air-to-air combat in mind are going to have their IR signatures reduced as much as possible, yes? The above quote seems to indicate to me that this has very likely been achieved to the point of being tactically significant.
I'd also be hesitant to say something like "an AIM-9X can always shoot down an F-22 in its range" because while the missile may be capable of doing so, the sensor systems onboard the shooter platform may not be sufficiently up to the task of detecting the F-22 such that the shot becomes a possibility. It's more complex than the missile simply having the capability in and of itself to intercept "target x" under certain circumstances.
LO, or "stealth" if you prefer, isn't just a matter of defeating radars. Remember that these aircraft, from the F-22 to the PAK-FA, are developed by professional organisations who spend billions upon billions of dollars to achieve LO solutions. It's reasonable to expect they've considered IR seekers and the threat they pose, don't you think?
I'd also be hesitant to say something like "an AIM-9X can always shoot down an F-22 in its range" because while the missile may be capable of doing so, the sensor systems onboard the shooter platform may not be sufficiently up to the task of detecting the F-22 such that the shot becomes a possibility. It's more complex than the missile simply having the capability in and of itself to intercept "target x" under certain circumstances.
LO, or "stealth" if you prefer, isn't just a matter of defeating radars. Remember that these aircraft, from the F-22 to the PAK-FA, are developed by professional organisations who spend billions upon billions of dollars to achieve LO solutions. It's reasonable to expect they've considered IR seekers and the threat they pose, don't you think?
As far as I know, firing a AIM-9X doesn't require any lockon by the pilot. It can find the target after it's launched.
Lower speed with no afterburner, B-2 has smaller heat signal than F-22. But it's no way escaping a common infrared camera during Paris airshow as widely known. And it's impossible to completely hide the high engine temperature from the background as engineering commonsense. We don't know the classified info about F-22 or T-50. But we understand the law of physics, don't we? No matter how capable F-22 is, it has to abide by the law. It is not the God.
Last edited by lizs; September 16th, 2010 at 12:33 AM.
As far as I know, firing a AIM-9X doesn't require any lockon by the pilot. It can find the target after it's launched.
But how do you know when/where to launch the missile? You need to know the target is there before you launch, otherwise you're taking random shots in a gigantic three-dimensional space, which isn't going to work. The missile still requires some form of targeting data, whether it's delivered before or after launch - if you cannot gather that data, the missile isn't going to be effective.
FYI, the sensor system by which the AIM-9X would attain a lock is through the missile's IR seeker itself - but from what I understand this has typically been a pre-launch activity in the past, the missile's seeker seeing the target and giving the pilot a tone prior to launch. In modern air warfare of course there is the potential for high off-boresight shots that require lock-on after launch, but you still have to be able to designate the target for the missile otherwise you will have no targeting data by which to guide the missile after launch, so yes, lock-on is required.
Quote:
Originally Posted by lizs
Lower speed with no afterburner, B-2 has lower heat signal than F-22. But it's no way escaping a common infrared camera in Paris airshow as widely known. And it's impossible to completely hide the high temperature from the engine nozzle. We don't know the classified info about F-22 or T-50. But we understand the law of physics, don't we? No matter how capable F-22 is, it has to abide by the law. It is not the God.
While the laws of physics are well understood, I do not understand them sufficiently to make claims about classified military aircraft that incorporate IR reduction technologies. Remember we're not talking about reducing an IR signature to "zero", we're talking about reducing IR signature sufficiently as to make detection and tracking by weapons systems more difficult. You don't need to break the laws of physics, you need to work around the limitations of sensor and weapon system technology. This is a very different thing.
As far as the Paris airshow goes, I believe gf0012-aust (a mod here) has set people straight about that event in the past, though I can't remember the details so I'll leave it to him if he wants to chime in or not.
Look, I'm not saying IR detection is going to be totally ineffective, nor am I in any way saying the F-22 is godlike (far from it, if you want my opinion). That's not my point at all. My point is that IR seeker technology for air to air missiles is nearly half a century old - and that it's unreasonable to expect this form of technology isn't considered when designing a modern LO aircraft, because low observability is NOT something that's related solely to radar cross section, but to radar, IR, electromagnetic and other . What I'm saying is that IR seekers are not a "silver bullet" solution to engaging LO aircraft, which I thought was your point - my apologies if it was not.
Airplane stealth technology poses a serious challenge to radar detection and missile guidance. But no airplane is invisible to infrared seeker, no matter it's a F-22 or B-2. As long as the friction between moving air and solid surface exists, a sensitive infrared seeker can always detect the thermal difference. Some seekers have an effective range up to 20 miles. And modern infrared imaging seeker will make any counter-measurement useless. So an AIM-9X can always shoot down a F-22 in its range.
That 20 mile range is only from behind where the engine exhaust is visible. The effective range is much shorter when viewing the aircraft from the front or side.
Quote:
Originally Posted by lizs
Old style radars use very long wavelength. It can detect stealthy targets but with very poor resolution(up to a few miles' error). It cannot guide any conventional missile accurately. But If we combine a medium-range surface/air-to-air missile and an infrared seeker, something like an R-27ET, then it's a stealthy target killer. Using datalink or radio command to guide such a missile to the approximate space near an F-22, the infrared seeker will finish the rest.
The radar type that you are referring to is Over-The-Horizon [OTH] radar. This radar works against some stealth designs because the wavelength can be tuned to match the wing span of the aircraft producing a resonance that cannot be masked, and because it is looking down on the aircraft due to the use of ionospheric bounce.
The problems with OTH radar include:
It cannot provide target elevation data.
It requires an antenna several kilometers on a side for the minimal accuracy you desire.
Because it also uses ionospheric bounce it has a minimum range of 800 km to 1000 km. Internal coverage will therefore be impractical except in the larger nations, and smaller nations may not even be capable of covering the normal zones for CAP.
It requires a huge power output to produce a useful return at ranges over 1000 km with the inevitable losses in 2 ionospheric bounce. Most installations are in uninhabited areas to avoid questions of safety to the surrounding population.
Very low signal to noise ratio means massive computational requirements. The more the better definitely applies here.
The ability to detect a particular size of stealth aircraft will depend heavily on the wave length being transmitted, which may be limited by the conditions in the ionosphere. Certain wave length may never be available, due to other natural phenomena.
It is fairly easy to spoof.
The idea is not new, it is just very limited in the locations where it would be practical to implemented. It is definitely not a panacea, even for those locations where is practical.
Lower speed with no afterburner, B-2 has smaller heat signal than F-22. But it's no way escaping a common infrared camera during Paris airshow as widely known. And it's impossible to completely hide the high engine temperature from the background as engineering commonsense. We don't know the classified info about F-22 or T-50. But we understand the law of physics, don't we? No matter how capable F-22 is, it has to abide by the law. It is not the God.
The infrared spectrum covers a large range, not all of which is useful for various reasons. Infrared emissions are defined by the various ‘black body’ formulas. The total ‘signal’ radiated [Stefan–Boltzmann law] is proportional to the 4th power of the temperature, while the peak wavelength is inversely proportional to the temperature [Wien’s Law]. You also need to have some means of identifying and rejecting false targets, and avoid blinding.
Your infrared camera (FLIR?) is designed for relatively low temperatures (long wave lengths), and is therefore a relatively short range device (low signal power). The camera was also working at night, viewing the aircraft against a cold sky, optimal conditions for the camera. It is very vulnerable to countermeasures, even a simple road flare can swamp the image.
IR homing missiles look only for higher temperatures / shorter wave lengths, to maximize effective range and false target rejection. If an IR homer operated using the same wavelength as a FLIR it would probably be very vulnerable to locking on to the moon at night as the sun in the day, and possibly the ground. The latest generation missiles look at several different frequencies and compare the results to further reduce false targets (like flares).
Airplane stealth technology poses a serious challenge to radar detection and missile guidance. But no airplane is invisible to infrared seeker, no matter it's a F-22 or B-2. As long as the friction between moving air and solid surface exists, a sensitive infrared seeker can always detect the thermal difference. Some seekers have an effective range up to 20 miles. And modern infrared imaging seeker will make any counter-measurement useless. So an AIM-9X can always shoot down a F-22 in its range.
Old style radars use very long wavelength. It can detect stealthy targets but unable to guide a conventional missile accurately due to its poor resolution(up to a few miles' error). If we combine a medium-range surface/air-to-air missile and an infrared seeker, something like an R-27ET, then it's a stealthy target killer. Using datalink or radio command to guide such a missile to the approximate airspace near an F-22, the infrared seeker will finish the rest.
You obviously completely misunderstand the point of low observability. It is not designed to make the target invulnerable, it is to allow the platform the capability to employ it's weapon systems before an opposition can target it.
So whilst an IR missile could indeed target an F-22 if close enough, the POINT is that no IR missile should be close enough to the F-22, before the F-22's own sensors and weapons can be employed against the IR missile launch platform.
An AIM-9X might be able to target and destroy an F-22. An F-22's radar and AMRAAM combination most definitely will enjoy a massive range advantage over any such threat.
It is to allow the platform the capability to employ it's weapon systems before an opposition can target it.
So whilst an IR missile could indeed target an F-22 if close enough, the POINT is that no IR missile should be close enough to the F-22, before the F-22's own sensors and weapons can be employed against the IR missile launch platform.
An AIM-9X might be able to target and destroy an F-22. An F-22's radar and AMRAAM combination most definitely will enjoy a massive range advantage over any such threat.
Plz read my post carefully.
No airplane is invisible in the radar frequency range below 2 GHz: A long-wave radar can detect a stealth target and roughly locate it, though not identify it. So the POINT is that such a radar can guide a IR missile close enough(say, 2~3 miles) to an F-22.
Ground-base radar or AWACS will outperform any fighter radar in range, and surface-to-air missile or long-range air-to-air missile guided by them can finish this job.
Last edited by lizs; September 16th, 2010 at 06:57 PM.
USAF Cruise missile, a solution from enemy shoot down??!!!
Ladies & Gentlemen,
Really have gotten the bull by the horns w/ this apparent easy look & shoot down
capability from enemy installations at will??! Can you believe their is already
a workable solution of which I shall not inform you of due to the fact that we are still
engaged w/ the enemy in Afghanistan. Our pilots & those drones are still the very hot defense
capability and shall endure through the length of any qwagmire; both now & in the near future.
That has got to be quickly appraised during and after skirmises where our enemies are.
deeply concerned @ why, where, what, who, when. Those were the concerns that I
experienced when patrolling anywhere boomers can go freely today!!! It has been said for
instance that on 22 May,1968; USS Scorpion was taken out w/just one aerially launched
torpedo onboard a Soviet Hormone helicopter, somewhere in the Atlantic Ocean.
No airplane is invisible in the radar frequency range below 2 GHz: A long-wave radar can detect a stealthy target and roughly locate it, though not identify it.
Could you quote an reputable source for this claim. IEEE L-band at 1 GHz - 2 GHz, has been claimed on some blogs to be able to see through stealth, but that is all speculative. Given that it is already used for air traffic control and long range search radars that seems highly unlikely. Everything I have seen reads more like marketing hype.
Could you quote an reputable source for this claim. IEEE L-band at 1 GHz - 2 GHz, has been claimed on some blogs to be able to see through stealth, but that is all speculative. Given that it is already used for air traffic control and long range search radars that seems highly unlikely. Everything I have seen reads more like marketing hype.
I am not a professional in radar technology. But you may find an easy read in
en.wikipedia.org/wiki/Stealth_technology
in the chapter of "Low-frequency radar".
BTW, air traffic control radar requires very high resolution to avoid collision accident. That's different from a "blur" radar mentioned above.
I am not a professional in radar technology. But you may find an easy read in
en.wikipedia.org/wiki/Stealth_technology
in the chapter of "Low-frequency radar.
I would suggest that you re-read the article. The critical words are “Shaping does not offer stealth advantages against low-frequency radar. If the radar wavelength is roughly twice the size of the target, a half-wave resonance effect can still generate a significant return.”
A F-22 is 18.9m long and 13.56m wide. Which value dominates may depends on the orientation of the aircraft and the transmitter. The minimum wavelength that can produce this effect is therefore 27m, or a frequency around 11 MHz. The only radars that uses this frequencies in this range are Over-The-Horizon radar, and the ‘Chain Home’ system used by the British at the start of WWII (which it should be added could not detect aircraft below 500’)
I covered all this, except the calculations and history, in the #5 post on this thread.
I would suggest that you re-read the article. The critical words are “Shaping does not offer stealth advantages against low-frequency radar. If the radar wavelength is roughly twice the size of the target, a half-wave resonance effect can still generate a significant return.”
A F-22 is 18.9m long and 13.56m wide. Which value dominates may depends on the orientation of the aircraft and the transmitter. The minimum wavelength that can produce this effect is therefore 27m, or a frequency around 11 MHz.
You took the concept too rigid. The geometry doesn't necessarily mean the overall dimension of an airplane. It can be part of the airplane, such as the vertical tail and wingtip. Suppose F-22's wingtip chord is 0.5m, then a double of it is 1m, corresponding to a frequency of 300MHz. This is ICBM warning radar's frequency, which goes straight and doesn't require any ionospheric reflection. It can be made as a phase array radar. Is it easy to deceive such a radar?
Are we looking at the issue too narrowly? Its not just a passive fight. EW jammers are going to be present. Aggressor ground based radar is going to be targeted by ARMs. AESA-based jamming makes it difficult to ID emitters as well. Anyone with no EMCON is going to be a flashing lightbulb.
I think there's a reason why fighter radars are x-band. If the other bands are that useful in fulfilling the fighter radar requirement, wouldn't it have been the preferred bandwidth choice? There's a lot of theory out there but I still haven't seen an actual anti-stealth fighter in operation yet.
Ladies & Gentlemen,
.
