F-16.net

Enthusiast Joined: Aug 18, 2005 Posts: 55 Status: Offline

I'd like to hear your thoughts on the F/A-22 being detected by radar. A lot of people here keep saying things like 'undetectable' and 'invulnerable' (even pilots, who should know better), and I think we all know that's not the case. Sure it's probably the least detectable combat a/c ever made, but it's not invulnerable.

It can supposedly get within slammer range of an F-15 before being detected, which is great, but as we all know with the advent of AWACS, fighters don't like using radar to try and find something because it's like using a torch in the dark (your prey can see the beam and therefore knows where you are). Plus, you can get within spitting distance of an F-15 if it's not looking for you. Wink

What I'm thinking is a radar site like JORN could pick up the F/A-22, and do it from far enough away that the RAAF could scramble fighters in time to protect JORN itself. Plus JORN is really low frequency compared to airborne radar (to get the over-the-horizon coverage), so I'd guess the F/A-22's RAM and structure wouldn't be anything like as effective against it as against microwave radar. Any thoughts?

Plus, the F/A-22 is designed to provide an ultra-low RCS from the front, but spikes against the flat surfaces. If you used a bistatic system, with a high energy radar transmitter a long way away, but receivers on the ground out in front of the radar, it could a) increase detection range (no longer requires a round trip back to the radar), b) pick up on more favourable reflection angles from the a/c, and c) the receivers wouldn't be putting out any energy, therefore could not be detected and destroyed. They could be hidden anywhere, even out on fishing boats, or on the roof of a hospital, depending on how much the operators don't like Geneva...

JORN also uses this idea partially, because the energy is coming down from the ionosphere to the a/c, getting a much more favourable reflection than head-on.

I guess, however 'stealthy' you make an a/c, it's still a lump of material up in the sky, and enough energy will generate a detectable response, even if the people living around the radar start having funny looking kids because of all the radiation. Smile

F-16.net Sponsor

This message from our sponsor will disappear if you log on as a member.

I very much agree with you, These techniques, together with better signal processing and passive searching will make stealth a lot less useful, and IMHO it might have been better to give performance a higher priority and do stealth only in detailwork, Imagine the pure performance of the "non stealthy fighter" that has the same $$$ behind in R&D and production then the F22. Couple that with a ramjet missile and you have a incredible machine, too.

Well. hard to predict the future but all that money (and performance compromises for stealth) are a risky bet

Hi Catisfit, this myth has been beaten on several threads. First, one has to keep in mind how the F-22 will be used; you don’t send them carelessly to any hotspot and expect them to do their job with full impunity. Second, a lower RCS is always a tactical advantage regardless of advancements in Radar technology. In the case of the F-22, stealth is coupled with an incredible array of sensors on a superb launching platform. There won’t be anything better out there for a long time; it is the whole package which makes an F-22 an incredible bully. Should it ever find itself in an unfavorable situation (AWACS + many fighters), it has the option of taking down a few, wait for reinforcements or returning to base. This is why I don’t think anything in the sky will be able to harm it.

Also, while systems like JORN might be useful in detecting stealth aircraft, they are also vulnerable (at least the transmitters) to cruise/balisitic missiles within the first couple of hours of a war. Mobile stations have to deal with Wild Weasels as well.

Well said Pat1

Some more comments:

Low frequency radars are highly susceptible to noise so even though "typical" LO treatments get less effective at lower frequency (unless tailored for those frequencies), the ability of a radar to actually find anything gets harder. Usually a wash. Also note I said "typical" in quotes. I am not going to talk about what the Raptor can or cannot do nor will I address whether it can be lumped into the "typical" category or not. I don't want the men in black to pay me a visit, nor do I want to put my USAF brethren in harm.

Bistatic...to date none of our potential adversaries has come up with a truly effective bistatic system. Keep in mind it takes more than simply catching an off-axis reflection. You have to know the exact time it left the transmitter AND becasue you've added another variable to the mix (the angle of arrival is no longer fixed to the physical angle of the antenna), you have now created a 2x2 matrix of solutions rather than a single point solution. This means the processing has gone up by a factor of 4.

With datalinks, today's fighters have significantly fewer reasons to transmit with their radar. Hence harder to find. Stealth is cool, but the advent of truly useful theater-wide tactical datalinks is (in my mind) a more significant reason why we will still kick anybody's A$$ that messes with us.

Bottom line. Stealth is not a panacea. however, you combine that with datalinks, a simply outstanding set of sensors that can soak up any EM that's out there, and a pilot vehicle interface that is so intuitive that it boggles the mind, and you have an air superiority fighter than will rule for as long as we can keep them flying.

Also, Stealth does not make one invisible...merely harder to see. But also keep in mind that seeing tour opponent is only the first step. To kill him yu have to find...track...launch (with more tracking from a smaller sensor)...and then, assuming you got close, fuze the warhead. To survice, all we have to do is break one of those links or degrade them all. So you picked up a blob a gazillion miles away on JORN...now what are you going to do?

hansundfranz wrote:

I very much agree with you, These techniques, together with better signal processing and passive searching will make stealth a lot less useful, and IMHO it might have been better to give performance a higher priority and do stealth only in detailwork, Imagine the pure performance of the "non stealthy fighter" that has the same $$$ behind in R&D and production then the F22. Couple that with a ramjet missile and you have a incredible machine, too.

Well. hard to predict the future but all that money (and performance compromises for stealth) are a risky bet

True, but imagine the F/A-22 with a Ramjet missile: It's supposed to launch supersonic anyway, the range on it would give reach out and touch someone a whole new meaning. But the great thing, at least in my understanding is that the shape of the F/A-22 not only gives aerodynamic benefits, but also stealth. I guess if you put enough dollars into any non-L/O fighter you'll eventually get one...

Elite 1K Joined: May 26, 2005 Posts: 1127

Here's a question, are there any projects on the books to give the Raptor an anti-radiation missile?

Enthusiast Joined: Jan 14, 2004 Posts: 87 Status: Offline

Guysmiley wrote:

Here's a question, are there any projects on the books to give the Raptor an anti-radiation missile?

I'm not sure there is that much futute in anti-radiation missiles. With a good enough firing solution an SDB will do the job just as effectivly for a lot less $$$.

-MArk

Aren`t JORN radars very large? I dont know if there is a profusion of mobile low frequency radars. I have read that these type of radars are limited in accuracy because of the long wavelengths they use and also limited by the number of frequencies they can use because of many other systems that use them.

Roscoe seems to have hit the button, it is one thing to detect the F-22, it is entirely another to "lock" onto it with a weapons system. Apparently stealth aircraft have to be only a few kilometres away to get a decent lock.Counter-measure, fly around it! Biststic systems would be more capable, yes. The problem is where the hell do you place transmitters and receivers and how many do you need!!!

The real advance in radar technology seems to in computer processing power and algorithms to process data and actually classify small returns, rather than filter them out. That seems the only danger to stealth. A UK firm demonstrated a technique using the humble cell phone network to detect stealthy aircraft. There are hundreds of radio transmitters and receivers that already cover whole countries. You use those as your bistatic radars, after all, radar is only radio waves. Then very powerful processors for signal processing and some clever software and algorithms for filtering to build a target picture. This research was on the net and then got pulled....
Don`t panic people, it was all over TV news stations as well so I am not giving anybody any ideas!
Theory is fine, doing it is entirely another. Don`t forget, radar can be jammed.
Heat signature seems more of a worry to me with stealth, RAM coatings turn radar energy into heat I believe.

The biggest advantage for the Raptor apart from stealth is supercruise in my eyes. The air warfare book will have to be re-written because of that ability. Energy (speed) = advantage! This ability and stealth will keep the F-22 way out infront for many years. Any technology made to counter stealth faces countermeasures to negate it.

Elite 1K Joined: May 26, 2005 Posts: 1127

The trouble with long wavelength (low frequency) radar is that the antenna gets larger as the frequency gets lower. You aren't ever going to see a low frequency radar guided missile.

As far as the cell phone detection systems, if a country is at "no-kidding" all out war with the U.S. their cell towers aren't going to last very long.

Quote:

Heat signature seems more of a worry to me with stealth, RAM coatings turn radar energy into heat I believe.

Hi snypa777,

This is so negligible, it is irrelevant...

Thanks for the heads up on heat signature Pat1. I realise now that RAM wouldn`t be used if it significantly raised skin temperature and energy levels would be very low in that process anyway....! Supersonic flight would present more of a problem, especially if sustained.

Guysmiley, I guess just a couple of JDAMS in the right places on critical components would see off a cell phone network! You would`nt need to take out the entire network, just drilling a few corridors through the coverage to your targets would do the trick!

Quote:

True, but imagine the F/A-22 with a Ramjet missile: It's supposed to launch supersonic anyway, the range on it would give reach out and touch someone a whole new meaning.

Yeah, a pity they don´t fit in the weapons bay

Quote:

But the great thing, at least in my understanding is that the shape of the F/A-22 not only gives aerodynamic benefits, but also stealth. I guess if you put enough dollars into any non-L/O fighter you'll eventually get one...

Everything in engineering is a compromise. There is no free lunch. The fact that it has fixed inlets alone is a major backdraft for performance.

Quote:

I'm not sure there is that much futute in anti-radiation missiles. With a good enough firing solution an SDB will do the job just as effectivly for a lot less $$$.

-MArk

Suppossedly the newest versions of the AMRAAM will have SAR/IR and a home on jam/radar mode. Again, that's suppossition, but it doesn't seem like a stretch.

Why is it not possible for the -22 to have variable inlets? I don't fully understand this stuff yet, but it would seem that you could either do that, or something to compensate for it.

Enthusiast Joined: Aug 18, 2005 Posts: 55 Status: Offline

Thanks all for your insightful replies.

Your point (Roscoe) about the complexities of the return in a bistatic system is well made. It would be a complicated system, but given the people and technology we have nowadays, nothing like impossible. Speaking from a software point of view, without knowing on exactly what bearing the transmitter sent the radar signal would mean that you couldn't get distance information from the return found at the receiver, but you'd know azimuth (and elevation, with more equipment) of a spike at that receiver. So you'd need to triangulate two receivers to get a point fix. To get distance from receiver (and so only need one receiver to get a point fix), you'd need to 'sign' the radar signal on bearing from the transmitter, so when you got a spike, you could figure out the bearing it was sent from the transmitter, and therefore narrow it down to one possible location per rotation of the transmitter, which would give one plausible result and a couple of ludicrous ones (if your transmitter completes one revolution per second, you'd get images at +/- 300,000km, which are obviously inaccurate!).

As for picking up a spike on JORN, well once you know something's there, you can vector something in to intercept, radar off. If the F/A-22 is trying to be stealthy, you can be damn sure it's not spraying its radar around the sky, so you could get in close enough to light him up and launch while he's still trying to figure out who the hell you are and where you came from, after all, he's stealthy, right? His AWACS might see you if you engage too far away, so you'd need to let him come close enough to avoid that, but not close enough to take out your radar, that's where the huge range of JORN is an advantage.

Snypa, cellphone towers sound interesting. As for them not lasting long in wartime, well, if your radar can see far enough, you can protect them. They're not exactly irreplacable, and they're easy to hide (they don't need to be on the towers we put them on Wink

).

F-16.net

Forum: F-22A Raptor

F/A-22 radar detection