Introduction to Crosspol Jamming 04
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- เผยแพร่เมื่อ 5 ก.พ. 2025
- This video provides a brief introduction to Crosspolarization (Crosspol) jamming as a countermeasure against radar homing missiles.
Cognitive Crosspol jamming: • INVICTA Cognitive Cont...
The intention is to promote informed scholarly discussion, and to make the professional EW community aware that this countermeasure is an option against real-world missiles for which there are few countermeasures options.
This includes current- and next-generation missiles with circularly-polarized seekers using technology that appears to be borrowed from 5G and driverless cars. Examples include Neptune, which appears to be circularly polarized, and variants from Russia, China and India.
Explanation of circular pol XP: • Crosspol Against Circu...
As mentioned in the video, Crosspol appears to be a particularly interesting option against radar guided hypersonic missile threats, for example the Chinese DF-21.
Crosspol Overview: 1:36
Definitions 2:41
How To use Crosspol 6:10
How Crosspol Works 7:00
A Missed Explanation 10:53
Radome Effects 14:05
Crosspol and Hard Kill 17:01
Conclusion 18:23
I am not afraid of AI. This video was recommended to me 2 years late.
so I'm just a dumb ham with a technician license and a long history of playing games like Harpoon so this channel is like catnip
There is no such thing as "just a dumb ham"!
Invisible, unrecognized, and unthanked cornerstone of civil defence you boys are. Hold fast.
Thanks for the video, it was really interesting. XP sound like a great idea in order to defeat radiation seekers.
I'm thinking about how to defeat the next generation of missiles designed to protect against XP softkill measures. The one that comes to mind would be a trinity of antennas, each with a π/3 polarization skew compared to the others, ensuring that they'll not crosspolarize at the same angles. Having the antennas so close to each other means that no XP could affect them all unless three specific XP jammers would tightbeam directly and specifically into the antenna reflector with no spillage over the others. This sound only possible through lasters and would require centimeter-precision on a mach 2.5 moving object.
The onboard processor could cross-compare the three signals and their target detection, and detect an XP jamming on one by realizing one is skewed away compared to the other. It would then discard its data to favor the two remaining (clean) signals.
I'm however wondering about the feasability of a smaller antenna (or virtual array) for target acquisition since it would also require to lower signal gain and therefore risk being exposed to other forms of jamming.
Seems like one of the few channels with in depth explanation of such HF technology. If anyone knows any video or channel where the way modern (of the last decades) missile radar seekers actually function, please tell me!
I have read a lot of specifics and I do know a little bit about signal theory and HF (like modulation, ...), but I would really appreciate an extensive overview!!! THANKS!
I'll put something together. Anyone can get pretty far in understanding this stuff by following the constraints imposed by basic physical laws.
And there are so many revealing photos of seekers online. Here's the SA-6 for example, what an interesting feed th-cam.com/users/shorts89-HcFtpycs
Never seen a video more accurate on the subject than this. And I do work in the sector.
Feel like ive happened upon another un-mined youtube gold vein
I'm here a bit late but have a few questions;
Like what about the initial burn-through while trying to initiate the Cross-Pol EA techniques, seems that the very small crosspolar fields would correspond to a very low antenna gain wrt the Copolar return signal (especially from a ship sized target, note at time 2:34 your copolar beam is seemingly 20dBi > the crosspolar, wow that's nearly 128x weaker signal strength and I'd venture a guess that -20dB is at the low end of the loss typically associated with Crosspol). If any high power JECM technique was used to initially capture the seeker's AGC then the extremely low crosspolar signal would be even lower in the grass, wouldn't it? Aren't most jammers already hurting for enough power to cover a ship's signature, yet alone offest the 20dB cross polarization loss
Admittedly, once you have captured the radar and the antenna/missile has turned then you won't have any 'true radar return' to compete with, but the initial jamming signal would need to be very powerful to exceed the regular copolar signals and when it does your jamming signal will drive the seeker pretty far off-axis and the missile will quickly go back into acqusition mode (ouch and that could hurt if you were an Atlantic Conveyor, or the original target is still within the FOV). Additionally, if the initial crosspolar signal is too far off the initial vector won't the track processor detect an acceleration, velocity, or angle gate anomally (isn't that why we walk-off the RGPO). Your tri-angular cross-pol steering waveform seems to partially address the walk-off although it seems to not have a 'Hold-off' phase and the receding leg of the triangular wave would pull the track vector back to the real target/ship???
Also, it would seem quite simple to devise a ECCM capability; i.e. having a dedicated crosspol receiver channel and use it's feed as a subtractive signal to delete from the main channel, similar to the sps-49's side-lobe suspression? Or maybe just add polarization filters into the radome (like you mentioned below in the SA-6 wire grid response)??? Kind of bold comment for you to claim universal countermeasure (time: 18:55ish) when such seemingly simple ECCM techniques could be developed or are already are in use???
Only a fellow EW practitioner would be able to write your thoughts and ask your questions, good to meet you.
An open forum is not the place to answer your insightful questions, though they do all have answers. Were we collaborating in a secure environment on a lucrative-for-me project I would lay out the whole smash of connected evidence so you can decide for yourself.
To the present: The waveforms shown in the various videos are for education purposes, and are not the advice I would give in real-world operations. The simulations shown are genuine representations of real-world effects for a generic-but-realistic missile engagement. The range gate position and seeker mode are intentionally incorrect.
The various videos I have produced are for education purposes, intended to raise enough questions in the minds of EW subject matter experts, such as yourself, that they choose to check certain preconceptions about Crosspol, as I have checked.
Add jog detection to the list of technologies to revisit, and over-water propagation.
Our community is where it is, and ship defence against missile attack is where it is, because we have very gradually replaced the difficult approach of analytical thinking and mathematical analysis with the lazy path of empirical observations.
Fact is, we need both. It's called the Scientific Method. I learned it when I was 10 yrs old, and with few exceptions I DO NOT see it being practiced in the EW community.
Here are a few of points:
- you are correct, Crosspol cannot compete directly with skin echo, the range gate has to be moved
- Key point: when drawing conclusions about the relative gain of copolar and crosspolar antenna patterns, the gains must be compared at the same angle, e.g. comparing the copol gain to the peak crosspolar gain is meaningless because they happen at different angles; it's a proxy for other things
- missiles fall on a spectrum of vulnerability to to Crosspol jamming: at one end, very easy to beat. At the other end, impossible to beat. All real-world missiles lie between these two extremes.
Whether or not to invest in and field this technology depends on the answer to this question: "is it worth the cost to defeat the missiles that can be beaten by crosspol with, say, 85% probability of success with 95% confidence?"
I don't know the answer that question! But I do believe that the people who control the money are married to hard kill and offboard solutions partially because they don't know any better, and partially because of powerful lobbying by large defence contractors who provide those solutions.
And I believe that a large segment of our EW professional community, the part that provides advice to whomever assigns "Program of Record" designations, has accepted the provably-wrong proposition that it's impossible to use active onboard countermeasures like Crosspol to protect ships. So they just stopped looking.
And once you stop looking, unless you have by God entirely and exactly the final answer, you're kaput in the water. Because no more information is coming in.
This. Can. Last. For. Decades. One misstep, decades.
Anyway I like you wrote.
thank you for uploading!
If your task is ship defence against radar homing missiles, this can be made to work. あなたは正しい道を進んでいます。
th-cam.com/video/VfOyKr7R38w/w-d-xo.html
th-cam.com/video/oDukOiY283s/w-d-xo.html
This XP looks to me quite easy to defeat using polarisators and polarization rotating / variable elements
Fair enough; how would you do it?
The Colour Wheel shows it's colour's till you spin it then it goes white.
What's going to happen if you spin the jammer @ 8 hertz?
You'd be doing it wrong.
@@skyindustries so it's looking for a stable cockup and not a white screen?
Seriously I'm trying to see this in Frequency.
I'm interested in cooking this out if my white screen does confuses the hell out of a seeker what does flipping the polarity 90deg's
@ apologies, I'm not follow what want effect you want to have, can you explain? What's does "white screen" mean?
This is fascinating... I wish I could understand it though.
I'm very interested in RADAR technology and I have looked into it *kind of* deeply, but nowhere even near this level.
As far as I go I still struggle to understand the concept of electromagnetic waves being 'polarized' as in... how come they have a magnetic component on the horizontal axis and an electric one on the vertical or vice-versa, and what/how this actually affects the wave itself.
Try studying some abstract math since it is surprisingly helpful in building intuition. There are some videos on YT that try to explain how category theory and geometry work together in an intuitive way and you don't have to actually understand the math itself.
For example: consider each point carrying more information than just a pointy vector. How would you go about knitting multiple spaces together in a way that makes sense and carries all the information you care about? Say we have an "electric field" space and a magnetic space, now we want to knit them together to make real space; would knitting them together build new structures like polarization?
Great video . Put how much data did you give are enemies
About as much as is online about how to build Fat Man or Little Boy.
Making something that works, not so easy...
Well done Sir!
Any idea what seeker head an exocet uses?
is this why the P-15 AShM was so often easily jammed?
And how the SA-6 was countered?
I don't know what the thinking is about countering the SA-6, but the designers were clearly concerned about Crosspol. The antenna has a wire grid over the reflector aperture, you can see it in this spectacular video: th-cam.com/video/TMECE9J8j-Q/w-d-xo.html
The grid will reduce some of the crosspol from the feed, but won't do anything to fix the radome effects.
Does Crosspol only work against seekers with parabolic reflectors, or radomes?
What I mean is, would a flat ground based PESA be imune to it?
(Just trying to make sure I understood how crosspol works)
A ground-based PESA will have a crosspolar gain determined by the crosspolar gain of its radiating elements. Put a curved radome over the array and the crosspolar gain will go up.
Same story for a slotted waveguide flat plate array antenna in a seeker or aircraft; the underlying antenna will have nearly zero crosspolar gain, but it will be added by a radome.
If the flat plate array is made from radiating elements that have a high crosspolar gain, the overall antenna will have a high crosspolar gain. Google "array element factor" to understand this better.
Can you talk about self propelled decoys that carry active jammer and how to counter them?
I've seen this before ;O)
image change at 18:02; the only way to make that type of change is delete the old video then post an updated one
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I don't know what that means...