Project RAINBOW - not halted after Phila. Experiment

The same group of scientists that were reported to be responsible for the infamous "Philadelphia Experiment" were a sub-function within Project RAINBOW. The technical research continued in other functions. It was the follow-on group to this that was later able to create electronics warfare pods for the jets by the time of the Vietnam War. By using electromagnetic projections they could disturb the radar signals of surveillance and targeting radars used by our enemies.

Within another two decades, they had also created the PHASED ARRAY early warning radar systems. These were then additionally able to be placed into systems that could detect and register enemy artillery shells immediately after they were fired, then could calcualte their firing point, and feed the information to the computers controlling the integrated artillery batteries so that they could have artillery rounds already in the air and en route to the enemy artillery positions by the time the enemy artillery shells landed in our territory.

The ongoing development of the electronics warfare systems aboard our fighters and bombers are derived from the original Project RAINBOW research.

With that said, can we really de-bunk the reports of what supposedly occurred with the Philadelphia Experiment. After all, the systems in the electronic warfare packages on our current aircraft would have seemed impossible to the scientists in WW II.

That is interresting, that experiment always smelled fishy to me.

I believe much more is hidden in those programs.

Do you have links or reference I can read?

Thank you for the post.

I cannot directly give you information about this, but I would recommend that you do some research on HOW the electronics warfare equipment of the USAF and Navy function, because their mode of operations would provide significant clues to my statements.

Sorry, but that's the best I can do for you.

Here is a good place to start:

www.es.northropgrumman.com...

Here is another excellent site.

www.designation-systems.net...

Has anyone looked u these resources and relaized that the ALQ pods cause the airfcraft to be "invisible" to enemy radar? Wasn't that the original purpose of Project RAINBOW?

reply to post by Truth1000


Yup. The original intent, depending on whom you speak to, was to make (at that time) the radar crossection of a naval vessel virtually non-existant. Though many people believe that by saying they were attempting to make the ship invisible to radar, somehow visual invisibility has supplanted that fact in the years since. For them to have halted after the Eldridge would have odd and unwise as during that period radar was coming into it's own as a very effective means of detecting threats at a distance. Thus negating that advantage would have been a top military priority. Alot of the technology gleened from that was packed into the EA-6B Prowler which has become a premier electronic warfare platform for the Navy. [atsimg]http://files.abovetopsecret.com/images/member/0382c144ce22.jpg[/atsimg]

Obviously the RCS reducing technology also made it's way to the U-2, Oxcart and the current generation stealth aircraft and newer air superiority fighters. The project since has reportedly changed monikers more than a few times as the technology upgrades abilities.

Excellent point, my friend.

Early radar evasion techniques included "window," which was just aluminum strips loosed from "counter-radar" aircraft. That was the situation when RAINBOW was started. There was a TRUE need for anti-radar capabilities. The "legend" of the Philadelphia Experiment totally ignores the real electromagnetic effects they found that could disrupt radar beams, and disturb rebounded radio-electric signals as they tried to go back to the sending radar set. THIS was what RAINBOW was really all about.

Think about this: there were no transponders or IFF sets back then. The technology needed to be produced. Who was going to produce that technology?

reply to post by Truth1000


Here is a little info on current gen electronic warfare suites by Raytheon. That particular link is for the ACES system but also has a link for ASPIS. With the miniturization of computer systems and exponential increases in computing power, what once took an entire aircraft now can be attached via pod or even a modular, server type, insert in most fighters. We've come a long way.

While most people wouldn't think about this kind of research with Raytheon, they were a major contractor for the USAF and for NASA. That technology was developed by scientists, who worked under the names of all kinds of classified programs.

If you want to know where to look, start with the dollars. Follow the money and you'll follow the research!

Follow the money AND the patents. One of the downsides for a gov't trying to keep tech secret is the need to make money off of it.

Originally posted by Truth1000
Has anyone looked u these resources and relaized that the ALQ pods cause the airfcraft to be "invisible" to enemy radar? Wasn't that the original purpose of Project RAINBOW?

Oh, come now. This is totally incorrect. No, they do not cause the aircraft to become "invisible", nor do they reduce the radar cross-section. Neither does chaff.

Nor can you "disturb rebounded radio-electric signals as they try to go back to the receiving set". At least not in the sense of modifying them somehow.

Somewhere around 2002 PhantomWorks had a "special effects suite" that is still quite highly classified out on the RCS test range at Holloman. Now THAT one has the option of "being invisible" for quite a range of radar frequencies, even against chirp, but not so much against UWB (yet). It can also displace the return for most radars by quite a distance, or return a stationary echo, or for some radars it can make the echo appear to be going backwards.

Even for the radars it can't be totally invisible against, it can buffalo the range gate/filter software on most of them by returning anomalous dopplers, a lot of radars will filter out what returns they DO get, thinking it's noise.

For what it's worth, what you hear about "the Philadelphia Experiment" is a cover story for something that ended up being a lot different than what it started off as, but it's one of the bigger military tech stories of all time. One day I'm sure they'll talk about it. I'd say, in about 50 years.

edit: got the dates wrong - they had it in the lab in 2002, it was fall of 2004 when they took it to Holloman.



[edit on 15-5-2010 by Bedlam]

Basic radar theory.

A radio wave emanates from a radar antennae, then passes through the air, contacts a radar target, bounces back to the radar site, and the site can perform RAdio Detection And Ranging, which is what RADAR stands for.

How do you defeat radar?

1- destroy the radar site

2- decrease the rebounded radar signal because of aircraft manufacturing

3- drop aluminum strips, that cause so many radar reflections that the true targets can't be identified (highly primitive)

4- cause the radio waves approaching the aircraft to be partially disrupted, so that they poorly rebound to the radar site

5- send alternate radar signals to make the radar site's signals un-readable

BTW, the better you do #4 and #5, the harder it is for any enemy radar to effectively monitor your mission's progress.

This is extremely basic, but things that need to be understood before trying to go any farther in tracking down this technology.

Originally posted by Truth1000
Basic radar theory.

A radio wave emanates from a radar antennae, then passes through the air, contacts a radar target, bounces back to the radar site, and the site can perform RAdio Detection And Ranging, which is what RADAR stands for.

Before you get going too far down that road, I design parts of military radar and military comm systems for a living. Just sayin'. Don't try to teach your grandmother to suck eggs.

How do you defeat radar?

1- destroy the radar site

Such as using an anti-radiation missile...

2- decrease the rebounded radar signal because of aircraft manufacturing

By use of RAM, appropriately shaped structural members that tend to trap reflections inside the plane, and skin shaping using the edge-wave method. Been there, done that, got a vector processing engine for both linear and curved surface Ufimtsev calculation and simulation at work.

3- drop aluminum strips, that cause so many radar reflections that the true targets can't be identified (highly primitive)

Still works, you'll note that TACDS drops chaff in addition to other countermeasure.

4- cause the radio waves approaching the aircraft to be partially disrupted, so that they poorly rebound to the radar site

Don't know who told you that one. You need to go look up "superposition" as applied to radio waves. Multiple sets of radio waves crossing a volume interact within the volume according to superposition, but do not affect each other outside the volume, having passed through, it is as if they do not exist for each other. You can't beam something at an incoming or reflected radio wave to make it go away.

5- send alternate radar signals to make the radar site's signals un-readable

That's what's happening with ACES, ASPIS and the rest.

BTW, the better you do #4 and #5, the harder it is for any enemy radar to effectively monitor your mission's progress.

5, yes. 4, doesn't exist.

This is extremely basic, but things that need to be understood before trying to go any farther in tracking down this technology.

You might try a master's in comm theory EE. It helps me a lot when I'm designing radar equipment.

Seriously, there's no magic way to emit something that eliminates radio wave in free space. You could, if you had every square centimeter of the plane covered in little discrete emitting surfaces and were towing a few dozen super computers, possibly emit a very structured coherent conjugate wavefront that would superpose at the receiving antenna to sum your reflection to zero. But in a real universe, that's not going to happen. Which is why PhantomWorks and SkunkWorks don't do it that way.

I think what you're seeing and not following is that with a DRFM jammer, you can vary the apparent RCS of the false targets it generates, but not the aircraft itself. You can also vary their position fore and aft, if the search radar is using regularly timed pulses, aft only if they're using random delayed pulses, and you can cleverly generate off-track spoof images if you identify the search radar by its emission signature and work the sidelobes of the antenna. But in order to do that, you have to be intimately familiar with the emitting system. DRFM jammers are also not so good against UWB radar, or some types of chirp. You can, in fact, design a system that will spoof most DRFM jammers into giving away the "real" echo by just diddling the chirp and pulse timing the right way.

Originally posted by Truth1000
4- cause the radio waves approaching the aircraft to be partially disrupted, so that they poorly rebound to the radar site

Are you trying to describe active cancellation? It's sort of hard to tell the way you're describing it.

Let's assume you're trying to describe active cancellation but not describing it properly.

Active cancellation does not "affect the incoming radio signal so that it reflects poorly making the airplane invisible to radar".

What it does is emit a conjugate return so that the spoof signal and the aircraft's reflection cancel at the receiving antenna, like I was describing. It doesn't do diddly squat to the incoming radio signal - it can't. It doesn't even really do squat to the outgoing reflection - can't do that either. What you can do is try to establish a superposition at the receiving antenna so that at the receiving antenna, the sum of the echo and the spoof are as close to zero as possible.

This doesn't make either signal go away in flight, it just sums them to something close to zero at the receiving end, sort of the same way your FM radio in your car fades in and out as you drive in a city where multipath echoes from the buildings can sometimes sum to near zero and leave "dead zones".

There are a lot of problems in doing this, as I said. One way that was proposed to do it was to have an active coating that was basically a plastic sheet of little wideband transmitters that would emit a cancellation wave as they picked up the reflection from the plane and re-radiated it dinked in phase as it came out of the sheet. That patent is Navy.

The problem comes in that your impinging radar wave can hit at any angle, and you don't know what the generating radar is at first, so you don't know the characteristics of the antenna on the receive end. The angle it hits at will cause a return from the plane that is complex in terms of phases and amplitudes, since it will hit different structures first, and the amount of return you get from each structure will vary also on the angle of impingement. So what you have to return as far as a cancellation function is nasty and varies with the radar that's scanning you, the angle it's hitting you from, the distance to the radar, and where in the pulse you are - you have to generate an attack, sustain, and decay phase set.

If the radar that's hitting you is chirping, you not only have to deal with the leading edge echo set being different from the sustain echo set, you have a sort of non-stop leading edge problem with the frequency changes that takes a LOT of computation, you also have to change the return constantly based on the changing aspect you are presenting to the radar as you maneuver or just fly away from it, which changes the angle and distance parts by itself.

All that is multiplied in spades if you're getting hit from more than one radar, to the point that you just about can't do it effectively if you're being imaged in more than one direction. AESA can do single radar active cancellation, there are a few other add-on boxes that can, ACES/ASPIT do not, that I am aware of.

Even with all that supercomputer number crunching to get this to work, it still doesn't make you invisible, btw, because you can never do it perfectly, and you have to identify the transmitting set before you can do a good job of it. On top of which, systems that do randomization in pulse and chirp characteristics make it nearly impossible, and UWB isn't cancellable. Active cancellation is a lot more effective on lower frequency sets, too, not so much on high frequency stuff.

edit: AESA can do it for most of the forward hemisphere, but not the rear of the plane

second edit: the distance mostly comes in as a "am I fairly close" issue. Once you're "far away" it doesn't matter so much. The problem is, if you're far away, you'll be hit with what is a nice approximation of a plane wave, that is, the conical section that the main lobe is putting out will be essentially flat by the time it gets to you. That simplifies things A LOT. If you're closer, the leading edge of the wave may look spherical, which complicates the returns, badly. Most radars aren't capable of resolving the signature on the leading edge of the return, but if you're spoofing for a plane wave and you're close, the summed leading edge of your return will be a noise burst because your plane wave conjugate spoof return will be wrong for a semi-spherical main lobe.

A very few of the newest radars can analyze the first few hundred ns of leading edge features and make a good guess at what sort of plane it is, and what angle it's presenting.


[edit on 15-5-2010 by Bedlam]

[edit on 16-5-2010 by Bedlam]

Funny story - the A12 carried an early active cancellation module. The Soviets discovered that you could use a bistatic radar setup and the cancellation would often make the RCS larger instead of smaller.

The "active skin" might work better - maybe. But these days, they're exploring other options, since UWB radar is THE upcoming thing, and you're going to play hell with actively cancelling it.

Bedlam,

You are doing a very good job of bringing out key information, especially in one of the important areas to which I referred. Keep going along this line you've started, and also think about what actually causes a reflection of radar signals. You seem quite well informed, BTW - good job!

reply to post by Truth1000


If you're talking about changing the refractive index of the plane so that it doesn't generate a reflection at all, by diddling the relative permittivity and permeability around the craft, that's what I was talking about with the PhantomWorks project in my first post.

The generation I metamaterial (although they called it a left-handed magnetic material then) coating allows "invisibility" as well as the generation of quirky nonsense returns, including single off-track ghosts, reverse or zero Dopplers and the like, none of which the add-on boxes can do.

They had it in 2002, and took it to the field test in 2004, IIRC, which is well ahead of the MSM's "Harry Potter cloak" stories.

edit:

And if you're talking about the real story behind the Philadelphia Experiment, I sort of mentioned that in the first post too...do you understand what it was supposed to do? And do you know the rest of the story? That's a deep rabbit hole, and doesn't have squat to do with the Bielek crap, other than its function as a cover story. It's also not one of those things I'd be posting on ATS, I certainly don't...verbum sapientum...

[edit on 17-5-2010 by Bedlam]

October 28, 1943. .---was not the end-not at all , not all are gone or wipedout from then. ->