All sensors and weapon systems have their limits, but the advantage that the RWR has over the radar in terms of first detection is not one of them. The figures cited by Blue Apple make this clear, and you have offered no refutation of these.

I assume you meant to say something other than you did.

As for Blue Apple’s example, why would I need to “refute” it? I never said that it was impossible for a RWR to detect a radar first, only that the reverse was possible. I have the much easier job in this debate…

First off, Blue Apple’s example ignored signal processing, but setting that aside…

If we were to decrease the range of the scenario, the propagation losses would decrease, until such a point where the radar’s superior gain would result in it receiving a more powerful signal.

A radar operating below that range, and employing intelligent power management could then ensure that it was able to maintain its track on the target, while staying below the RWR’s detection threshold.

In the real world it is not necessarily the case that the radar would actually need to receive a stronger signal than the RWR. Again, signal processing and other issues could significantly shift the range beneath which the radar could maintain its track while denying the RWR a detection via power management.

Whether and the extent to which this range would be tactically useful would depend on the RWR, the RCS of the aircraft carrying it, and of course the radar attempting to track the target. Clearly the more capable the radar, less capable the RWR, and larger the RCS of the aircraft the greater the radar’s advantage. The radar can be expected to maintain its output at the minimum level necessary to maintain its track, whether or not this would be sufficient to prevent a detection by the RWR would be scenario dependent.

What would this look like to a pilot? At long ranges the pilot relying on his RWR could enjoy a first detection advantage. As distances closed the radar could them subsequently detect the fighter. If the distance continued to close the RWR could then lose the track entirely as the radar decreased its power. (where, and whether this would happen would depend on the specifics…)

If a radar were willing to accept decreased detection ranges, it could also make intelligent assumptions about the RCS and RWR of its target, and preemptively decrease its power output such that it could expect to detect a target before a RWR was able to detect it, albeit, at fairly short ranges. This would make the most sense for a ground based radar with a very high-gain antenna. (and a strong desire to avoid eating a missile)

Another scenario would have the threat radar activate while the fighter relying on its RWR was well within its range. Once it had detected the fighter it could then decrease its power as described above. The fighter in this case would most likely observe a momentary detection, followed by nothing. (and then perhaps a missile…)

Well, if you want to speak of practical experience, during the industrial phase of my career I worked on the development team of an airborne radar-warning system. Since then, I can modestly claim to have been responsible for teaching the rudiments of EW to many dozens of engineers.

Uh huh

(I’ve taken the liberty of removing the bold red lettering from the original – writing something in bold and red does nothing to increase its veracity.)

I’m not sure what amuses me more – the idea that processes in the real-world do not conform to the underlying mathematics that describe them (the simulation and modelling so widely used in weapon-system design rely on this relationship), or the idea that the designers of radar-warning receivers do not understand the limitations of the systems they are creating.

I don’t know what amuses me more, that one would so smugly suggest that my explanation does not conform to the “underlying mathematics” or that RWR designers are not aware of the limitations of their systems.

I have often found that those with the most confidence in their theories have the least practical experience.

This quote sums it up nicely:

“In theory there is no difference between theory and practice, in practice, there is.”

You should direct your attention here (pg 156) for a simple explanation (that will not, shockingly enough, violate any laws of physics or mathematics):

http://books.google.com/books?id=pd71EFWpVZMC&pg=PA155&lpg=PA155&dq=%22low+probability+of+intercept%22+radar+%22low+power%22&source=bl&ots=tJsQg1HFnh&sig=b5S6Rs8C_rk56_R1i0cedvL_6yI&hl=en&sa=X&ei=wT5PUa-cPKm80AG4sYDYBA&ved=0CGkQ6AEwCA#v=onepage&q=%22low%20probability%20of%20intercept%22%20radar%20%22low%20power%22&f=false

Summarizing now for the layman… antenna gain matters a great deal, as does signal processing, and in the real world there are in fact situations where a radar can detect its target before the RWR detects the radar.

This is most likely to happen when dealing with:

Extremely large/high-gain radars, large RCS targets (and/or a geometry that produces a RCS spike), shorter ranges (which will generally aid the radar in this scenario) and of course older and/or less sensitive RWRs.

Yes the RWR has some substantial advantages if you limit yourself to a superficial look at the equations, but the radar also possesses significant advantages and in actual practice it is not a given that a RWR will detect the radar first. Even in situations where the RWR does detect the radar first, it may not do so at an appreciably greater range than the radar is capable of tracking its target.

Any designer of RWRs would of course know this.

A simple analogy might make help. If a sentry is put into position on a totally overcast night, given a powerful torch (flashlight to out US forum members), and told to use this to search for old Mercurius, who is going to try to reach his position from some unknown direction, all he can do is wave the beam of light from one side to another until the presence of his target can be established. Once I have become close enough that my natty business suit is reflecting a detectable amount of light, the sentry will see me.

But on my side, all that I need to do is to spot the light from his torch. Even with my ancient eyes, that should be fairly easy at a long range.

Giving our sentry binoculars or even light-intensifying goggles will make his detection task easier, but even then I would question whether there would ever be a situation where I could not yet see a glimmer of light from the beam of a torch pointed directly at me, but would be reflecting enough light to be visible to the wielder of that torch.

Analogies can be useful, but also very misleading. With proper optics a telescope/night vision device can achieve several orders of magnitude of intensification.

http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1644

The flashlight in the woods scenario also does not account for the fact that the holder of the flashlight knows where to look as he directs his beam out into the distance, and can thus take advantage of a range of signal processing techniques unavailable to the man wandering in the dark scanning for a flicker of light…

One would imagine this is specifically when it comes to WVR? As the raptor has demonstrated SC @ Mach 1.72, Has a much much lower signature etc etc .. Most jocks that i have spoken have told me that event he raptor with its very very good low speed High AOA work is at a disadvantage of sorts when up against a capable fighter with HMS/HOBS….that is also probably why the DOD has included HMS HOBS as a part of the 6 billion dollar upgrade for the raptor…

The Germans also said the F-22’s advantages in BVR were “overwhelming.”

What these guys were doing was taking totally clean Eurofighters and flying them against F-22s in “fair” WVR fights. (entering with equal speed, altitude, situational awareness, no pre-merge shots, etc.)

It doesn’t really say much about how things would work out in the real world because those sorts of fair fights simply wouldn’t happen, but I imagine it is fun training.

Once again, just google “passive geolocation” & “Kalman filtering”, a RWR can provide a track, this problem has been solved 20 years ago. Your knowledge base is (way) out of date.

Now, as already said it will be a low pk track but the main idea is to use this track to either cue other sensors (radar or long range TV) or simply avoid the detected aircrafts.

I have said over and over again that it is possible to do some tracking of an emitter. What is not possible is the sort of tracking a radar itself provides. You may know someone is out there, and roughly where they are, but the area of uncertainty will be large, and the reliability of the track low.

At short enough ranges this may not matter, but for longer ranges?… there is just no comparison. There are a lot of aircraft today flying with EW systems comparable to Spectra, but that hasn’t diminished the value of a modern radar, though it has necessitated changes in tactics.

Any way you cut it, being able to actively scan the skies in front of you and see who is out there well beyond their ability to do the same to you is a big advantage. No other sensor, no IRST, or RWR, or TV system is able to provide a similar capability.

The antenna size is a complete red herring, it has nothing to do wth the discussionat hand and it is obvious that a RWR antenna is never going to be a large directionnal antenna like a radar and frankly I suspect you’re just trolling.

This by itself reveals all we really need to know. 😎

This is physics, but it is also plain ordinary common sense. If antenna size didn’t matter you would see designers doing fun things like spreading them all over the aircraft like they currently do with RWRs…

Naturally antenna size does matter, and to a huge degree.

That’s why smart systems don’t rely on a single sensor at a time but on a combinasion of several sensors, active or passive operating on different part or the spectrum, working together, whose data are computed and fused to create reliable tracks.

What a smart system seeks is to generate the most accurates tracks with the less possible active emissions. Hence Radar, and laser emissions must be especially well managed.

Of course

So what is the detection range of a su-35 on a Rafale ? and what makes you think that spectra will not be able to pick up su-35 radar emision beyong that range. The size of the Su-35 antenna alone ?

Detection range is going to depend on a lot of factors.

…and no, antenna size alone doesn’t mean much. There were some big antennas back in the 60s and 70s… but they are still thoroughly obsolete today.

A RWR receives a focused high energy radar beam while the emiting radar has to pick up scattered waves which are far weaker (especially from a low RCS a/c like the Rafale) and which energy per surface unit is a function of the inverse D²

Of course.

The radar will be working with a far weaker signal, both because of distance and because only the small minority of the energy reflected from the target ever actually returns to the radar. That said, the radar is going to be far more sensitive. How things actually balance out will depend both on the specific radar, RWR, and all the other usual factors. (loadout, geometry, etc)

My primary point is that it is not a given that a RWR will always detect a radar before the radar is able to track its target. That may be the more common outcome, but it is not a given.

Well, given that it takes around 10 seconds to get a first fix and less than one minutes to reach ful accuracy, this fighter has better be manoeuvring a lot and emit very intermittently.

In which case its usefullness in a patrol trying to defend its country’s airsapce is going to be quite limited…

“full accuracy” :rolleyes:

What constitutes “full accuracy” is going to vary widely depending on the emitter, and its motion.

Let me repeat for you once again. A RWR is not a radar, nor a substitute for a radar. It will -never- provide a similar level of information.

They can detect the presence of a potentially hostile emitter. They can provide a bearing, in some cases a pretty precise one. Some can also make gross estimates of range…

They do not “track” an opponent in the same manner that a radar does.

Do you understand what sensitivity means in the context of this discussion? Here is a hint, it has to do with receiver noise figure, bandwidth, noise threshold.

It has nothing to do with the size of the antenna, your “answer” misses the point by a mile.

Better than you do, clearly.

Start here:

http://en.wikipedia.org/wiki/Antenna_gain

Simplifying this for you…

The Su-35 has a very large, very high-gain antenna relative to any RWR. It is optimized very carefully for its own operating frequency and is highly directional.

The RWR is not nearly so large or optimized. The RWR needs to cover a much wider swath of the sky, and it needs to cover a much wider frequency range. It is also quite simply much smaller and more simplistic and thus less capable of distinguishing faint signals, all other things held equal.

This is the difference between this:

and this:

so prove it that Rafale can have higher altitude/speed for BVR shot than Tornado ADV?

Ah yes, the good old make a ridiculous claim and then demand others disprove it approach…

Rafale is certainly more agile aircraft than Tornado but it does not mean Tornado top end is slower than Rafale or less capable radar in Tornado.

Again, spec-sheet top speeds are very misleading. No 4th generation aircraft actually operates near its maximum speed. Additionally, while it is true that going higher and faster is advantageous for BVR shots, that really only matters if you are comparing similar missiles.

A Meteor is a far longer ranged and more energetic missile than is available on any threat aircraft, meaning that the Rafale would have a substantial advantage even if it were operating slightly lower or slower.

Su-35 engine power is way more than Growler. so certainly more powerful and heavier pods to higher altitude/speed it can carry.

:rolleyes:

This would be pretty comical if I didn’t suspect you were serious. The Su-35 has bigger engines, therefor you think it can carry more pods and be a better standoff jammer? 😀

The point i am making is that F-18E despite reduced RCS measures need this super expensive version with all external pods. so slighlty reduced rcs of Rafale is certainly not an advantage.

You don’t seem to know what point you are making.

The Growler supports all US aircraft, from the F-22 and B-2 to the B-52. It is a dedicated support asset and it works with all aircraft across all the services.

The existence of the Growler doesn’t say a thing about the RCS of the baseline Super Hornet or any other aircraft.