Author Topic: The end of stealth? New Chinese radar capable of detecting ‘invisible’ targets  (Read 4793 times)

adroth

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The end of stealth? New Chinese radar capable of detecting ‘invisible’ targets 100km away
Breakthrough relies on ‘spooky’ phenomenon of quantum entanglement
PUBLISHED : Wednesday, 21 September, 2016, 12:43pm
UPDATED : Wednesday, 21 September, 2016, 11:11pm

http://www.scmp.com/news/china/article/2021235/end-stealth-new-chinese-radar-capable-detecting-invisible-targets-100km?utm_source&utm_medium&utm_campaign=SCMPSocialNewsfeed

A top Chinese military technology company shocked physicists around the world this week when it announced it had developed a new form of radar able to detect stealth planes 100km away.

The breakthrough relies on a ghostly phenomenon known as quantum entanglement, which Albert Einstein dubbed “spooky action at a distance”.

The figure in declassified documents is usually a tuned-down version of the real [performance]MILITARY RADAR RESEARCHER
China Electronics Technology Group Corporation (CETC), one of the “Top 10” military industry groups controlled directly by the central government, said on Sunday that the new radar system’s entangled photons had detected targets 100km away in a recent field test.
That’s five times the “potential range” of a laboratory prototype jointly developed by researchers from Canada, Germany, Britain and the United States last year.

America’s Defence Advanced Research Projects Agency has reportedly funded similar research and military suppliers such as Lockheed Martin are also developing quantum radar systems for combat purposes, according to media reports, but the progress of those military projects remains unknown.

< Edited >

r3mu511

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^as science-fiction like as this all sounds it is actually based on real-life physics... this is the actual 2015 publication on quantum illumination at microwave frequencies: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.080503, and this is a copy of the paper: http://arxiv.org/pdf/1410.4008v3.pdf

whether the chinese engineers were able to overcome the practical limitations as outlined in the research paper (ie. the limitations due to the storage required to hold the linked quantum idler field) is the main question with regards to the range they have claimed they are able to achieve (fwiw, in the research paper a practical range of ~12 km or so is cited, as limited by the requirements for storage of the idler field, so a chinese claim of 100 km is pretty impressive)...

(disclaimer: my specialization in physics back in university was electromagnetics and not quantum mechanics so my reading of the research paper linked is very superficial)

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as to why this would have an impact for RF LO/VLO aircraft (ie. "stealth"), the theory of quantum entanglement (as far as my non-quantum mechanical brain understands it) is that the two photons which have been entangled will be linked even when separated and thus a change on one of the photons due to the environment will be reflected in the linked photon... so if you retain one photon (in storage) and emit the linked photon, if this photon interacts with an object you can detect that interaction by observation of the photon you kept in the storage...

now considering that RF LO techniques rely mainly on redirection of the RF energy away from the source (ie. reflect the photon "away from the source"), or attenuation of the energy (eg. via RAM, ie. convert the RF energy to thermal energy)... then if the photon emitted either gets reflected in another direction or absorbed as a quanta of energy (and re-emitted as thermal energy), that effect on the emitted photon will be detectable as information from it's linked photon which is back in your storage, hence you would supposedly be able to tell that your emitted photon encountered some object out there even though you actually didn't receive back the photon you emitted... so effectively it mitigated the redirection or attenuation of RF LO techniques...

Ayoshi

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China offers anti-stealth radars for export | IHS Jane's 360 - 11 November 2016
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China's principal radar manufacturer, the China Electronics Technology Group Corporation (CETC), exhibited at Airshow China 2016 a number of air defence radars it claims can detect low-observable aircraft such as the Lockheed Martin F-22 Raptor and F-35 Lightning II fighters.

Chinese news media reported that these radars are being marketed for export to any country with a requirement to counter such stealth capabilities.

While the 2016 air show in Zhuhai is not the first venue CETC has exhibited such hardware at, the equipment on display reflects in part the claim made by some Chinese commentators that China has become the world leader in radars capable of detecting stealth aircraft.

Although exhibited in public, data on the performance characteristics to back up the cutting-edge claims is less forthcoming. Anti-stealth radars typically operate at frequencies below 1GHz, because low-observable aircraft are designed to minimise their cross section to radars operating within radio spectrum covered by the IEEE S, C, and X bands (broadly 2-12 GHz).

Chinese anti-stealth radars on display at the Airshow China 2016 in Zhuhai. From left to right are the JY-27A, YLC-8B, and SLC-7. Source: Via dy.163.com

r3mu511

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^the above article should probably be posted in the "Stealth vs. Low Frequency" thread (http://defenseph.net/drp/index.php?topic=158.0), as this thread is about quantum radars which operate based on the quantum entanglement principle and are not dependent on long wavelength/low frequency scattering phenomenon...

in contrast the chinese radars featured in the above article are the more conventional sub-L band type hence would be properly classified together with other low frequency sets (UHF, VHF, HF, etc.)...

Ayoshi

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https://www.janes.com/article/87495/china-working-on-terahertz-radar-prototypes

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China working on terahertz radar prototypes
27 March 2019

The report described the radars as “anti-stealth radars”, highlighting that one of the attributes of radars operating in the 300 GHz – 3 THz band is their ability to penetrate many materials to reveal objects under the surface.

This applies to the skin of stealth aircraft, resulting in return signals reflected from the aircraft structure that negate its stealthy properties. However, the report acknowledged that the atmospheric absorption of signals at these frequencies results in very short detection ranges that are insufficient to detect hostile stealth aircraft before they are in striking range.