Detection of Submarines

[Jemiba]

In a scientific magazine I found an article, explaining that a fish/submarine or everything
else moving under water, is displacing its own weight as a kind of pillar of water, which is
moving to the surface and so changing the water level, relatively to its depth.
(see the sketch as explanation ). This phenomenon is said to be used for the detection of
submarines. I know, that it is of course possible to detect the wake caused by a periscope or
even by a submarine at shallow depth, but I think that’s something different. Here it would
mean to find the “hump” on the water surface. Is this used and if, how is it done over the
constantly changing sea ?

 

[AeroFranz]

Good question. Also, what happens if the submarine is at rest? i am pretty sure the water around and especially above it is redistributed so that the sea surface is flat...

 

[Jemiba]

Of course, a stationary object under water won't cause disturbance of the
surface, but moving objects only. I think, there will be just very small changes
and I don't know, how they could be recognised, even in a calm sea, not to
mention higher sea states. I was astonished to read this in the mentioned article,
publshed in a reliable magazine, as a translation from an issue of American Scientist.

 

[Michel Van]

strange, i can recalled that US Navy look in 1980s for methods to scan the Sea level with laser or radar.
from space so exactly accurate as possible !

Wat came out was this map made with NOAA sat

can it be they tested this method for find under water Submarine ?

 

[r16]

ı remember reading such reports that there was no hiding for submariners anymore .I had somewhat felt sorry but I would hazard a guess but just a guess that IR detection of heated water around the submarine is far more easier than lasing wavetops .

 

[avatar]

oky totally thinking aloud here..

Is an analogue in the air possible, say with a satellite tracking system?

 

[Jemiba]

"Is an analogue in the air possible, say with a satellite tracking system?"

If I've understould your question correctly, I would say no as air is compressible,
but water isn't. that's the stated reason for a body moving under water, to constantly
press a certain volume of water upwards, as water flows around this body, so it cannot
be displaced to the fron and to the rear and not the bottom, too, but only upwards.
A good example as an explantion is someone, who is crawling under the carpet. ;D
Unfortunately, giving a number for the amount the surface would be raised in relation
to the depth of the object, was out of the scope of this article ( Spektrum Der Wissenschaft
.6.08, "Laufen=Fliegen=Schwimmen")

 

[robunos]

what about the 'seasat conspiracy', see here,

http://www.astronautix.com/craft/seasat.htm

i remember reading, but don't remember where, sorry, that the 'results that alarmed the pentagon', were that the satellite could detect submerged submarines with total ease, so it was squelched before the soviets found out and built their own version.
don't know how true this all is, but seems plausible.

cheers,
Robin.

 

[avatar]

If I've understould your question correctly, I would say no as air is compressible,
but water isn't. that's the stated reason for a body moving under water, to constantly
press a certain volume of water upwards, as water flows around this body, so it cannot
be displaced to the fron and to the rear and not the bottom, too, but only upwards.
A good example as an explantion is someone, who is crawling under the carpet. Grin
Unfortunately, giving a number for the amount the surface would be raised in relation
to the depth of the object, was out of the scope of this article ( Spektrum Der Wissenschaft
.6.08, "Laufen=Fliegen=Schwimmen")

Yes but a plane flying through air does displace some of it in all directions (motion in a fluid after all). again thinking really aloud and off the top of my head, isn't it possible to pick up the anomaly in air flow over a particular area?

 

[Jemiba]

"isn't it possible to pick up the anomaly in air flow over a particular area?"

If it is possible to measure the density of air from a (large) distance, this
could be possible, maybe ...

 

[mz]

Low frequency sound etc.

The nice thing with the sea is that water is incompressible and also that it has a nice relatively clearly and flatly defined upper surface where to do measurements on displacement.

 

[avatar]

what if you spray your airspace with certain "stuff" ( crude way to put it , but you get the idea) , I guess density differentiation would be possible..

 

[mz]

Of course, before radar, sound detection was very important in detecting enemy aircraft and was used extensively in WW2:
http://histru.bournemouth.ac.uk/Oral_History/Talking_About_Technology/radar_research/sound_detection_aforerunner.html

Nowadays with aircraft flying higher and faster it's of less use. If a craft traveling at Mach 0.9 can be detected when the sound (or air pressure) arrives from say 50 km distance, then the actual craft is already within 5 km. And this doesn't take into account the altitude.

Sonar can theoretically be used to detect low flying aircraft in the sea (one concern about the use of F-111 for anti-shipping roles in Australia btw) since the speed of sound is much faster in the water.

 

[Jemiba]

As I had absolutely no idea, what numbers we are talking about, I made a calculation for the following example :

A submarine of 5000 ts , with a length of 100m and beam of 10m is travelling in a depth of 50 m. The displaced mass of water will be lifted to the height of the submarine, but of course, due its viscosity will be distributed more and more in relation to depth. As an estimation, I set the cone along which the mass of water is distributed at 90°. Then, 5000 ts of water would be distributed over an area of 110m x 200m (to ease calculation, I used a rectangle ...) , this could mean a rise of the sealevel of about 20 cm, at least in the center of this area. A very rough calculation, of course, but I can imagine, that such change should be recognisable with proper methods.

 

[avatar]

20 cm ! that's a lot ! how did you arrive at that figure? the ocean that this submarine is operating in isn't really a confined space , and you are not accounting for currents..

 

[AeroFranz]

... this could mean a rise of the sealevel of about 20 cm, at least in the center of this area. A very rough calculation, of course, but I can imagine, that such change should be recognisable with proper methods.

Jemiba, I appreciate the effort everytime somebody takes the bull by the horns and does a reality check using numbers and physics, even if you have to make rough assumptions, so thanks for doing that.
This being said, i think the next obvious question would be how the radar (or whatever sensor you are using) distinguishes between the displacement wave of a submarine and a "regular" wave. Unless the sub is in a lake, there will always be some sort of wave motion. Maybe you have to look at the overall pattern and find the wave that is still 20 cm taller than the rest? ???

 

[Jemiba]

I was surprised, too, and honestly I have severe doubts. My very inaccurate
calculation is based on the statement in the mentioned article, that displaced
water will be forced mainly upwards, as, due to the incompressiblity of water, this
is the direction of the lowest resisting power. Due to the viscosity the amount of
water will be distributed over a wider area and I set the widening angle at 90°, which
I thought to be quite large. One factor I completely ignored, is the speed of the
submarine, as the effect will surely increase with higher speed. My submarine probably
is dashing really fast !
To make this clear: I won't take a ruler and try to measure a 20 cm higher sealevel.
But to me it seems, that this effect could produce a really measurable increase in local
sealevel in the range of some centimeters. If and how this is detectable, is another
question, sealevel is a statistically affair. What's the attainable precision and, probably
as important, the attainable resolution ? If a radar beam measures the value of sqaremile,
a local increase of some centimers probably won't be detected.

 

[Forest Green]

Armed with quantum sensors, France eyes leaps in electronic warfare

Quantum gravimeter technology, used for mapping the seabed, offers the prospect of surreptitiously tracking adversary submarines.

www.defensenews.com

PARIS — The French Navy took delivery of its first serial-produced, quantum-technology sensor this year, a quantum gravimeter used for mapping the seabed, the head of the country’s defense innovation agency AID said. Future uses of such sensors could be for navigation or detecting enemy submarines.

France in 2022 earmarked €1.8 billion, or U.S. $1.93 billion, to develop quantum technologies, a rapidly evolving field that exploits the laws of quantum physics to create new forms of computing, communication and sensing. Quantum gravimeters measure falling, laser-cooled atoms to detect tiny variations in gravitational pull, which could be used to detect the mass of an adversary submarine. There are no methods for submarines to shield themselves from such sensors, according to a 2020 policy brief from the European Leadership Network.

The gravimeter “is particularly useful for the first applications we’re doing here, mapping the seabed,” Aufort said. “But afterward, we can imagine other uses for the gravimeter, notably for positioning, notably for detecting the existence of a cavity on the seabed.”

France turns to AI for signals analysis in underwater acoustics war

French naval intelligence analysts want to hear a wrench falling in a hold in a faraway vessel, or its pumps starting up.

www.defensenews.com

 

[southwestforests]

what about the 'seasat conspiracy', see here,

Encyclopedia Astronautica Index: 1

www.astronautix.com

That link is coming up with the classic 404 not found.

Did find this about Seasat from same website,

Seasat

Seasat

www.astronautix.com

And ...

Playing in Google found,

https://apps.dtic.mil/sti/tr/pdf/ADA151283.pdf

SEASAT Report
K. Case
R. Dashen
W. Munk
J. Vesecky
K. Watson
E. Zachariasen
January 1985
JSR-83-203
Approved for Public release; distribution unlimited.

20. ABSTRACT (Continue on reverse side if necessary and identify by block number)
A brief overview of SEASAT and ship wake characteristics is given. -The authors
do not believe that the V-shaped wakes seen by the SEASAT satellite are I--
external waves because ship wakes are three to four orders of magnitude too
weak to explain the observed radar returns.
If the V-shaped wakes are not produced by internal waves, then by default they
must be manifestations of the Kelvin wake. Present understanding of rear axis
(Continued)
URITY CLASIFICATION OF THIS PAG E (When Data Entered)
19. KEY WORDS (Continued)
20 ABS RACT (Continued)
"-,generation of Kelvin wakes ("thin ship theory-- does not adequately explain
the effects seen by SEASAT)- non-linear effects probably need to be included.
Also ships propellor-generated Kelvin wakes do not appear to be strong enough
to create the wakes seen. - -.
Consequently, we are left with a somewhat unsatisfying situation. We believe
that narrow wakes cannot be produced by ship generated internal waves,
(except under extreme conditions) because these are too weak by three or four
orders of magnitude. Therefore, they must be due to the Kelvin wake. But we
have not yet been able to analyze the Kelvin wake sufficiently well theoreti-
cally to identify just which feature of the Kelvin wake SEASAT is seeing.

 

[dumpster4]

Researchers ask industry to investigate future muon particle beams for
electromagnetic weapons and sensors

"U.S. military researchers are asking industry to develop enabling technologies for a future atomic charged particle beam potentially able to destroy enemy electronics and weapons, as well as to inspect caves containing nuclear weapons or detect submarines in the ocean."

See:

Researchers ask industry to investigate future muon particle beams for electromagnetic weapons and sensors

DARPA MuS2 project seeks to create a source for a muon beam strong enough to support demonstrations of national security and scientific applications.

www.militaryaerospace.com

 

[dumpster4]

DARPA’s Secretive New Neutrino Detector Program Could Be A Game-Changer
for Global Underwater Military Surveillance

"However, solicitation documents obtained and reviewed by The Debrief show the program will be focused on detecting accelerator-sourced neutrinos. These types of neutrinos are human-generated using a particle accelerator to collide an accelerated beam of protons against a fixed target.

This suggests that DARPA may be exploring using neutrinos for long-range underwater communication or detecting clandestine nuclear activities, including tracking enemy nuclear submarines."

See:

DARPA's Secretive New Neutrino Detector Program Could Be A Game-Changer for Global Underwater Military Surveillance - The Debrief

DARPA is aiming to revolutionize global military surveillance and underwater communication using neutrino detection technology.

thedebrief.org

 

[DWG]

DARPA's Secretive New Neutrino Detector Program Could Be A Game-Changer for Global Underwater Military Surveillance - The Debrief

DARPA is aiming to revolutionize global military surveillance and underwater communication using neutrino detection technology.

thedebrief.org

Someone's been playing Traveller again! (Neutrino detectors are a high tech reactor detection system in Traveller)

That article gets very confused about how this is meant to work:

"By deploying accelerator-sourced neutrino detectors in strategic locations, the U.S. military could effectively track enemy nuclear submarines through the unique neutrino signatures produced by their reactors. "

Submarines don't produce accelerator-sourced neutrinos, the clue's in the words 'accelerator-sourced'. Nor are the detectors 'accelerator-sourced'. What they seem to be talking about is detection of accelerator-sourced neutrinos at a distance with something a bit more compact than IceCUBE, which is a kilometre a side. The only way I can see of using that as a submarine detection technology would be if you could use Cherenkov radiation to backlight a submarine for an optical detector. And that would work best in a confined body of water, which is what they seem to be looking at.

 

[dumpster4]

Possible game changer in detection of submarines

"China will try to use lasers, microwave radar and a lot of computation to detect submarines down to 500-meter depth.

Experiments carried out by the United States and former Soviet Union achieved maximum detection depths of less than 100 meters, according to openly available information. The detection depth has been extended in recent years by the US in research funded by Nasa and the Defence Advanced Research Projects Agency (DARPA). A device developed by DARPA, for example, was mounted on a spy plane and achieved reliable results at a depth of 200 meters, detecting targets as small as sea mines."

See:

Possible game changer in detection of submarines | NextBigFuture.com

China will try to use lasers, microwave radar and a lot of computation to detect submarines down to 500-meter depth.

www.nextbigfuture.com

&

US patents Quantum Entanglement based techniques for detection of stealthy Russian and Chinese submarines even under arctic - International Defense Security & Technology

The US Government has now tuned to Quantum sensors to detect stealthy Russian and Chinese submarines

idstch.com

 

[dumpster4]

Investigation of the Debye Effect for Submarine Detection

"The Debye effect is an acousto-electrokinetic phenomena which has not been extensively investigated to determine its potential for the detection of submarines. The Debye effect causes the generation of electric and magnetic fields due to fluid particle acceleration in an electrolytic solution (in this case the ocean). The effect results from the separation of charges due to differences in the masses and mobilities of the ions; in a moving solution the ions are drawn along differently by the moving fluid and are displaced relative to each other"

See:

(SBIR) Navy - Investigation of the Debye Effect for Submarine Detection

 

[TJDougherty01]

That link is coming up with the classic 404 not found.

Did find this about Seasat from same website,

Seasat

Seasat

www.astronautix.com

And ...

Playing in Google found,

https://apps.dtic.mil/sti/tr/pdf/ADA151283.pdf

Both SeaSat and the Shuttle employed synthetic aperture radar supposedly could detect small height changes in water from submerged submarines. The Russians also tried with satellite radar (mentioned in the Polmar & Moore "Cold War Submarines" book). Not much more was ever published on that, as I think the results were classified (or disappointing).

Russian submarines have had sensors with the acronym SOKS that have been attributed to detect submarines by wakes, radioactive traces and other measures. These have been around for a couple decades at least. These detectors are mounted on the sail and on a stub fin. The effectiveness is unknown

A number of recent advances appear to be in the prototype stages involving several non-acoustic measures to detect submarines. Items like using microwave radar (tried in the past) to detect subtle sea height changes and lasers to illuminate submarines are mentioned above. The article mentions: "Those laser beams can scan an area as wide as 100km, or concentrate on one spot just 1km wide". I'm not sure if that is some kind of raster scan by the laser, as the whole point of lasers is a narrow focused beam, not a broad area coverage. It would take a lot of power for a laser beam that can penetrate from space to great depths (500 meters) and have the reflected signal make it back up to the satellite detector. What about the effects of clouds? How effective these concepts are and to what depths they actually detect submarines is certainly still a question.

Magnetic detection has been around for decades, and I am sure is now much more sensitive than back in the P2V and P3 aircraft days with SQUID (superconducting quantum interference device) magnetometers.

 

[TomcatViP]

Probably evaluating height of changes in sea water as with a SAR.
The difference in scan coverage b/w 100km and 1km is the number of points evaluated for the detection: from wide area search to track.

Laser scanning is pretty casual today. But It all fall down to how you interpret data. But on that side, it should be relatively similar to SAR.

 

[dumpster4]

Seeing Underwater with Background Noise

"Noise surrounds any object immersed in the ocean; the object, in turn, modifies this noise field in ways that depend on the object's shape, composition and position. Ambient noise has a familiar optical analogue: daylight in the atmosphere. We can see and photograph outdoor objects because they scatter, reflect and otherwise modify the light in the air. Likewise, noise that permeates the ocean acts as a kind of "acoustic daylight." Recent experiments have shown that we can indeed create images of underwater objects by using ambient noise as a source of illumination. Our results are sufficiently encouraging that we believe acoustic-daylight imaging should prove useful for a variety of purposes, from harbor security to underwater mine detection."

See:

Acoustical Society of America - Seeing Underwater with Background Noise

&

https://buckinghamlab.ucsd.edu/research/adonis-acoustic-daylight-ocean-noise-imaging-system/

 

[dumpster4]

The Military Could Track Objects Underwater With Seal Whiskers

"Scientists in the United States and South Korea are working to fully understand how whisker tech works. The next step will be to make a high tech analogue that doesn’t involve using a seal’s whiskers, facial nerve endings, and brain.

If the tech can be put to sea, it could greatly increase the ability of ships, aircraft, and submarines to detect enemy subs underwater. Subs can evade passive sonar by coming to a full stop and being very, very quiet. On the other hand, even at a full stop a large, several thousand ton submarine is likely producing minute vortices, as current swirls past the boat’s contours. These vortices may end up being detectable. Furthermore, vortices linger in the water column for minutes or even hours, much longer than sound."

See:

The Military Could Track Objects Underwater With Seal Whiskers

Seals use their whiskers to quietly track their prey, an idea that could revolutionize undersea warfare.

www.popularmechanics.com

 

[dumpster4]

Russian submarines have had sensors with the acronym SOKS that have been attributed to detect submarines by wakes, radioactive traces and other measures. These have been around for a couple decades at least. These detectors are mounted on the sail and on a stub fin. The effectiveness is unknown

Not just Russian subs:

"The U.K. Royal Navy’s Trafalgar class attack submarine HMS Talent has arrived in the British territory of Gibraltar sporting curious new sensors on either side of its sail. We can say with near certainty that these are additions to an existing system designed to detect enemy submarines without the use of sonar that first appeared on the boat in 2019."


"As for what these sensors actually do, they are designed to detect other submarines beneath the waves via the changes in water density that they leave in their wake. These systems have historically been almost exclusively associated with Soviet and now Russian submarines. In that country, they are most commonly referred to collectively as examples of a System Obnarujenia Kilvaternovo Sleda (SOKS), or Wake Object Detection System.


There have also been reports in the past suggesting that certain SOKS variants could be able to detect trace amounts of certain chemicals in a submarine’s wake, including from temporary anti-corrosive coatings flaking off or byproducts from oxygen generation systems. Detecting minute increases in radiation levels from the reactors on nuclear-powered boats, such as the Trafalgar class, or elevated water temperatures from a submarine passing by, may also be among their capabilities."

See:

Royal Navy Submarine Appears In Gibraltar Equipped With Enhanced Wake Detection System

These somewhat exotic non-acoustic sensors that were once mainly found on Soviet submarines would help supplement sonar when searching for other subs.

www.twz.com

 

[DWG]

certain SOKS variants could be able to detect trace amounts of certain chemicals in a submarine’s wake,

Somewhat like early P-2s and P-3s fitted with diesel sniffers.

 

[dumpster4]

Nomad Atomics’ gravity sensor could revolutionise ASW, minerals exploration

"The portable gravimeter developed by Canberra-based Nomad Atomics uses quantum sensing to precisely measure gravitation, but is little larger than a shoebox and rugged enough to cart around on exploration trips.

Potentially, a precise gravity sensor could also detect a submarine underwater by its gravitational signature, which would have huge strategic implications."

See:

Nomad Atomics’ gravity sensor could revolutionise ASW, minerals exploration - EX2 for Defence Innovators

An Australian start-up company is poised to revolutionise the minerals exploration industry with a small device for precisely measuring gravity that is so sensitive it can detect even small ore bodies at greater depths than any other instruments in use. The portable gravimeter developed by...

www.ex2.com.au

 

[dumpster4]

New Sonar Sees Underwater From The Air, Promising To Transform Anti-Submarine Warfare

"PASS combines two advanced technologies to achieve this feat: laser-generated sound, and novel sound sensors.

A short laser pulse heats the water surface, causing it to expand rapidly and producing a sound wave. The sound radiates out and reflects back from the seabed or submerged objects, like a conventional sonar source. This eliminates the loss of intensity going from air to water."

See:

New Sonar Sees Underwater From The Air, Promising To Transform Anti-Submarine Warfare

A new type of sonar developed at Stanford University with funding from the U.S. Navy can see objects underwater from the air. This could transform detection of submarines and underwater mines.

www.forbes.com

 

[dumpster4]

Littoral Airborne Sensor/Hyperspectral

"The Littoral Airborne Sensor/Hyperspectral (LASH) imaging system developed by the United States Navy combines optical imaging hardware, navigation and stabilization, and advanced image processing and algorithms to provide real-time submarine target detection, classification, and identification in littoral waters. Operating in visible and near infrared spectrum (390 to 710 nm), LASH collects hyperspectral imagery using many spectral channels (colors) to exploit subtle color features associated with targets of interest. Developed as a pod-mounted system, LASH can be operated from a P-3C Orion, SH-60B Seahawk, or other platforms in support of anti-submarine warfare, mine detection, passive bathymetry, near-shore mapping, and land-based detection, discrimination and targeting."

See:

Littoral Airborne Sensor/Hyperspectral - Wikipedia

en.wikipedia.org

&

http://the.honoluluadvertiser.com/article/2003/Aug/19/ln/ln23a.html

 

[dumpster4]

Industry asked to develop magnetic anomaly detector (MAD)-equipped UAV for anti-submarine warfare (ASW)

"U.S. military researchers are asking industry to develop a small unmanned aerial vehicle (UAV) equipped with a magnetic anomaly detector (MAD) that can deploy from the U.S. Navy P-8A Poseidon maritime patrol aircraft to detect and track enemy submarines."

"The UAV should weigh less than 36 pounds, and be launched from an LAU-126A class A sonolaunch container in the P-8A aircraft; be able to fly for as long as 45 minutes at cruise speed; fly as fast as 90 knots; and be able to detect a target the size of a submarine.

Navy officials want the MAD UAV to be air-deployable from 500 to 25,000 feet altitude; be able to operate in salt spray in rain; search an area as large as four square nautical miles each hour; and provide constant target position with revisit rates of less than 10 seconds."

See:

Industry asked to develop magnetic anomaly detector (MAD)-equipped UAV for anti-submarine warfare (ASW)

Project seeks to launch a 36-pound, 90-knot UAV with magnetometer from a P-8A aircraft, with 45-minute endurance, to detect submarine-sized targets.

www.militaryaerospace.com

 

[GTX]

Industry asked to develop magnetic anomaly detector (MAD)-equipped UAV for anti-submarine warfare (ASW)

"U.S. military researchers are asking industry to develop a small unmanned aerial vehicle (UAV) equipped with a magnetic anomaly detector (MAD) that can deploy from the U.S. Navy P-8A Poseidon maritime patrol aircraft to detect and track enemy submarines."

"The UAV should weigh less than 36 pounds, and be launched from an LAU-126A class A sonolaunch container in the P-8A aircraft; be able to fly for as long as 45 minutes at cruise speed; fly as fast as 90 knots; and be able to detect a target the size of a submarine.

Navy officials want the MAD UAV to be air-deployable from 500 to 25,000 feet altitude; be able to operate in salt spray in rain; search an area as large as four square nautical miles each hour; and provide constant target position with revisit rates of less than 10 seconds."

See:

Industry asked to develop magnetic anomaly detector (MAD)-equipped UAV for anti-submarine warfare (ASW)

Project seeks to launch a 36-pound, 90-knot UAV with magnetometer from a P-8A aircraft, with 45-minute endurance, to detect submarine-sized targets.

www.militaryaerospace.com

I wonder if one could also do an equivalent with a Laser detection system instead of MAD?

 

[GTX]

Prospects for game-changers in submarine-detection technology | The Strategist

Anti-submarine warfare (ASW) has always been a game of hide and seek, with adversarial states looking to adopt and deploy emerging technologies in submarine stealth or detection to give them the strategic edge. The advantage ...

www.aspistrategist.org.au

 

[dumpster4]

DARPA Looks to Nature for the Detection of Submarine Drones

"The U.S. government’s Persistent Aquatic Living Sensors (PALS) program is a collaborative of researchers and defense companies on a mission to explore ways to leverage the sounds that permeate the ocean. The program includes a number of proposals for how monitoring the behavior of specific species might offer clues to the presence of non-living objects like unmanned drones.

As reported by Discover Magazine, the study of the oceanic soundscape which comprises sounds like the crackling of countless shrimp clacking together mixed with fish grunts, whale and dolphin calls and other such sounds might hold the key to revealing that a man-made intruder or drone is in the water!"

See:

DARPA Looks to Nature for the Detection of Submarine Drones

4 (1) Submarine drone technology is being examined from a unique and intriguing viewpoint by some scientists funded by the US military’s research arm, DARPA, the Defense Advanced Research Projects Agency who believe that the chorus of the sea might allow them to detect the near-silent passage of...

dronebelow.com

 

[dumpster4]

China Says It Is Developing a Laser Satellite to Spot (And Help Kill) Submarines

"Project Guanlan (“watching the big waves”) aims to create a satellite that can detect submarines 500 meters (1,640 feet) below the surface, far more than previous attempts by the United States and Russia.

Song Xiaoquan, a researcher on the project, said that if the project is successful, it will make the upper layer of the sea “more or less transparent,” according to the South China Morning Post.

“It will change almost everything,” Song said."

See:

China Says It Is Developing a Laser Satellite to Spot (And Help Kill) Submarines

No more stealth subs?

nationalinterest.org

 

[dumpster4]

Quantum magnetometer arrays for magnetic detection of submarines

"The new magnetometer, built by Xiaoming Xie and colleagues at the Shanghai Institute of Microsystem and Information Technology, uses not one SQUID but an array of them. The idea is that by comparing their readings, researchers can cancel out some of the extra artefacts generated by motion. This “would be relevant to an anti-submarine warfare device”, says David Caplin at Imperial College London, who works on magnetic sensors.

Researchers estimate that a SQUID magnetometer of this type could detect a sub from 6 kilometres away, and Caplin says that with better noise suppression the range could be much greater."

See:

Quantum magnetometer arrays for magnetic detection of submarines | NextBigFuture.com

On 21 June, the Chinese Academy of Sciences hailed a breakthrough – a major upgrade to a kind of quantum device that measures magnetic fields. Magnetometers

www.nextbigfuture.com

 

[dumpster4]

China’s terahertz tech heralds the future of underwater war

"The South China Morning Post (SCMP) reported last month that China has tested the world’s first submarine-detecting terahertz device based on next-generation communication technology. Researchers from China’s National University of Defense Technology published their findings last month in the Chinese-language peer-reviewed Journal of Radars.

The device identified tiny surface vibrations, reportedly as tiny as 10 nanometers, produced by a low-frequency sound source in the open sea. These waves can help find submarines and gather critical intelligence, such as noise signatures that can be analyzed to identify a submarine’s model. According to the research team, the technology “will have significant application potential in underwater vessel detection and other areas.”"

See:

China's terahertz tech heralds the future of underwater war - Asia Times

Chinese researchers claim to have discovered a new terahertz-based submarine detection technique, which, potentially coupled with advancements in sensor

asiatimes.com