Radar Active cancellation

Active cancellation is a theoretical military jamming system that involves the sampling of an incoming radar signal, analyzing it, then returning ths signal slightly out of phase, thus "cancelling" it out. While there are no official systems using this in service, it is rumoured to be in use on USAF Stealth Aircraft like the B-2, F-117, F-22A, and possibly the F-35. It is also speculated that the Thales SPECTRA aicraft protection suite also uses this system.

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So what do people think of this concept could it work with modern radar? Is it in use by planes right now?

I would imagine you would need massive computing power to calculate every possible variable of the planes radar return as the plane is ever moving, changing the angle of the radar waves hitting it in real time. Would it be able to handle multiple radars emitters?

Could a systems like this perhaps produces a "ghost" radar image of the plane if it couldn't completely mask its radar image? I would think if a system could mess up the radar return just enough to give a false position it would be very handy.

Originally posted by ShadowXIX
I would imagine you would need massive computing power to calculate every possible variable of the planes radar return as the plane is ever moving, changing the angle of the radar waves hitting it in real time. Would it be able to handle multiple radars emitters?

Could a systems like this perhaps produces a "ghost" radar image of the plane if it couldn't completely mask its radar image? I would think if a system could mess up the radar return just enough to give a false position it would be very handy.

You wouldnt need the massive computing power to be on board the plane. Working out the possible variables of the planes radar return could be done on the ground and then adjusted in the air as suitable.

It would only produce a ghost image if the timing of the return wasnt compleatly accurate. This is a great idea but i think that it would be almost impossible in real life especiallly if there was more than one radar aiming at the plane.

Justin

Computers are very good at adding up numbers - which is basically where the computer power is needed.

They should talk to my wife; she is a master at signal cancellation and disruption. I put the “signal” or my “vibe” out all the time, and she cancels them with absolute efficiency…

All jokes aside, I think this is one of the ways the B-2 makes itself disapear from radar. Sure its stealthy, sure its smooth, but from a look down / shoot down radar its like a barn door...but then the USAF say it isn't.... so how the hell do they manage that then?

Its first mention was in the early 1990's, and then kind of slipped off the radar so to speak, and only surfaces every now and again.

I'll dig for the article, but a Flight international editor got a flight in the B-2, and all flight, just 1 switch was taped over because of its sensitivity / classification. Makes me wonder just what it was....... active stealths my bet.

i think its used for long wave radar tha operate in HF,VHF,UHF bands (still less frequency than fire control radars) A phased aray or AESA radar would solve the problem of multiple mmitters and also u can have it hop frequencies faster than the enemy radar can for added efficiency. But its not perfect Ew radars msut still be taken out by low flying apaches and cruise missiles like GW1 but it could be used sometimes.

Originally posted by MadGreebo
I think this is one of the ways the B-2 makes itself disapear from radar. Sure its stealthy, sure its smooth, but from a look down / shoot down radar its like a barn door...but then the USAF say it isn't.... so how the hell do they manage that then?

Just because the US air force say something about one of their planes doesnt mean it is true.

Justin

er yeah Justin thats what I'm saying... a barn doors a barn door....

Any how, French seem to be in on this tech as well.

www.janes.com...

2000 article about Frances use of fledgling active stealth tech. I still believe its out there and in use some where.

Scroll down to the last aircraft mentioned, and theres a pic of the system mounted on a drone wing.

www.armada.ch...


[edit on 20/3/06 by MadGreebo]

Yeah, was going to say what Greebo said basically.

The Rafale was supposed to have some kind of active cancellation system.


One major, massive, insourmountable problem with it is this - active radar cancellation can only deal with one radar transmitter and reciever.

However, are more modern radar systems not one transmitter, multiple reciever nodes? To deal with this, you'd need cancellation transmitters installed in every part of the airframe to cancel the local wave reflection and not cancel the global reflection in one direction.

Heres an interesting read from janes defence. Has loads of different pics in it ( Pdf format) but its the comments from the Legendary Skunk works creator that makes you wonder.

Inventions 20 or 30 years old that are still cutting edge? sure as hell would love to see them in the light of day!

www.gyroscopes.org...