Ship to ship EW?

[LoBlo]

There's alot of data out there about softkills and jamming incoming missiles, but has anyone ever read anything about whether or not its possible to for one ship to completely jam another ships radar? There are rumors that the next generation EW system in development for the USN is powerful enough to jam orbiting radar satellites...

[Dr.Sid]

How does radar jamming work anyway ?
I understand that if you send the same frequency back all the time, radar can't detect target range. But it still can detect bearing, and for many applications it can be enough.

[PeriscopeDepth]

Originally Posted by LoBlo

There's alot of data out there about softkills and jamming incoming missiles, but has anyone ever read anything about whether or not its possible to for one ship to completely jam another ships radar? There are rumors that the next generation EW system in development for the USN is powerful enough to jam orbiting radar satellites...

That all depends on the power of the jammer and the power of the radar and the distance between them. Get close enough and any radar will burn through jamming. Nobody really knows when it comes to EW, it is a very sensitive subject.

PD

[PeriscopeDepth]

Originally Posted by Dr.Sid

How does radar jamming work anyway ?
I understand that if you send the same frequency back all the time, radar can't detect target range. But it still can detect bearing, and for many applications it can be enough.

No easy answer to that question. There are many methods of jamming. Bearing certainly isn't enough in most cases, range is very important in naval warfare.

From this (http://forums.frugalsworld.com/vbb/s...=jamming+works) thread, posted by mirv who is a USAF officer on an E-3 IIRC:
Quote:
Originally posted by Marlin
A radar signal is nothing more than a noise ping which has a frequency and a wavelength. A jammer trys to match the frequency and wavelength but at 180 degrees phase thus cancelling out the signal, but the jammer signal itself is a perfect source for your radar to detect.
[/b]

This is a pretty good thread. Finally some discussion that is doesn't have a lot of misinformation and someone who's done some homework. I only want to add a brief explanation about some jamming stuff. It's pretty geek, so bare with me.

And not to steal your thunder, what you've said is true from a basic point of view, but....jammers do a lot more than just that and radar energy is a bit more complex than just frequency and wavelength. Jammers have to "know" or determine a lot of characteristics about the victum radar.

The kind of jamming you described is called Inverse gain jamming and is typically used against conical scanning radars (like a AAA radar for example). Since conical scan radars use the phase of the target returns to generate error signals, an inverse gain deception jammer attempts to alter the phase (like you said) by inducing fake signals into the antennas. Also, by altering the amplitude of the signal, the jammer induces large errors into the tracking loop. To do this, the jammer must determine the frequency, PRF, and scan rate of the victum radar. It then transmits signals that change the phase and amplitude of the target signal, resulting in a signal 180 degrees out of phase with the actual target. This 180-degree error rapidly drives the antenna off the target and causes a break-lock. Cool eh?

Like I said in another post, there are TONS of jamming techniques out there, most/all of which Falcon doesn't do...there's false target jamming, range deception, range gate pull-off, angle deception, inverse gain, swept square wave jamming, velocity deception, velocity pull-off, doppler noise, velocity bin masking, monopulse deception, skirt frequency, cross-eye, terrain bounce and some others. Falcon is generic, but at least it denies/delays lock-ons until burn through, can cause break-locks and even provides a nice "I'M HERE!" target.

PD

[SeaQueen]

Originally Posted by Dr.Sid

How does radar jamming work anyway ?
I understand that if you send the same frequency back all the time, radar can't detect target range. But it still can detect bearing, and for many applications it can be enough.

Turning on certain types of jammers can definitely raise your electronic signature and make you more detectable to certain types of EW suites. Other types don't. Typically, though, when a jammer is turned on, it's because the enemy already has a pretty good idea of where you are or at least that you're on the way. The whole discussion of when and what to emit is actually pretty interesting. If you're a game theory geek, you can formulate EW in those terms.

[ASWnut101]

Or short and sweet. :

Imagine all your senses were in your ears. The ears emit a ping of noise, and listen for the return. Some kinds of RADAR jamming are like taking a super loud radio and putting it to your ear. Now try to hear the return.

[Dr.Sid]

I understand .. but why do I need the return where there is the radio playing ? It must be even easier for missiles to home on strong 'jammer' instead of radar returns.

[To be]

Active jammers work by (effectivly, see technical description above) sending false returns to the radar. Radar bounces a beam off an object, and waits for it to return. The jammers send lots of fake returns to hide your range from the radar, since the radar can't tell what return is real. But the returns are all coming from the target, so they are all on the same bearing. That is my understanding anyway.

[ASWnut101]

Originally Posted by Dr.Sid

I understand .. but why do I need the return where there is the radio playing ? It must be even easier for missiles to home on strong 'jammer' instead of radar returns.

Because they can't hear their own returns. They hear your "radio."


P.S. I may have not explained it well enough. I'll try agian.

(This is something you can actually try at your house) Imagine that your ears are a set of RADAR emiiter/receivers. Take a coin and toss it against a metal surface. The coin acts as your RADAR "ping," and the noise you hear from the impact of the coin is the return signal. Now, take a radio, put in the loudest, crappiest music you can find (preferably heavy metal ), and turn it on. Turn the volume up really loud. The radio acts as the enemy's jammer. Throw the coin again. What do you hear?:hmm: The music. You can't recieve the RADAR return. All you get is a mass of noise from everywhere. This is essentially RADAR jamming.

[PeriscopeDepth]

Originally Posted by Dr.Sid

I understand .. but why do I need the return where there is the radio playing ? It must be even easier for missiles to home on strong 'jammer' instead of radar returns.

This is true in some cases, particularly with modern AAMs. In these cases jammers are useful in denying a good enough firing solution (lack of range information). Once burn through occurs though, you are simply amplifying your location even further.

PD

[ASWnut101]

Which is why we need to invent a "Jammer on a string" concept for aircraft. Infact, for boats, you could do the same thing, just on a ballon teathered to Ownship. It would help stop burnthroughs, wouldn't it?

[LoBlo]

Originally Posted by Dr.Sid

How does radar jamming work anyway ?
I understand that if you send the same frequency back all the time, radar can't detect target range. But it still can detect bearing, and for many applications it can be enough.

I can't really add anything to what already been said except that I'm not sure of the details either. Though I know someone that designs them for a living... I'll ask him to give me the basics, though it will be over my head I'm sure.

I do know that there are systems in development to jam even IR and optical homing missiles with medium power lasers. Nothing like the power output to enable a hard-kill, but enough laser energy directed at the nose of the incoming missile to blind it completely.

[SeaQueen]

Originally Posted by ASWnut101

RADAR jamming is like taking a super loud radio and putting it to your ear. Now try to hear the return.

That's not quite true, there's also deceptive jamming where, the jammer emits false returns, creating the illusion of there being more than one target.

Electronic warfare has a lot of sublty involved, and is extremely technical.

[SeaQueen]

Originally Posted by ASWnut101

Which is why we need to invent a "Jammer on a string" concept for aircraft. Infact, for boats, you could do the same thing, just on a ballon teathered to Ownship. It would help stop burnthroughs, wouldn't it?

That's essentially what Nulka is. It's a deceptive radar jammer with a rocket to keep it hovering above the sea surface.

[ASWnut101]

Originally Posted by SeaQueen

That's not quite true, there's also deceptive jamming where, the jammer gets false returns, creating the illusion of there being more than one target.

Electronic warfare has a lot of sublty involved, and is extremely technical.

Ok, well some types of jamming work that way. That's the easiest concept, I think. I'll edit.