China's Blitzkrieg on U.S. Carrier

[gambit]

* Reconnaissance Satellites - I think you can look at the Ziyuan and Yaogan series of satellites that have EO, CCD and SAR sensors as possibilities here. They could also be talking about the FY series, which is actually expected to be a constellation of Earth Observation satellites. I think it's important that in the 18th Committee on Earth Observation Satellites plenary and workshop in 2004, they announced they would launch over 100 Earth Observation satellites. I don't know enough about this to comment on which specific satellites I think will be used for scanning ships, but the blog did mention that China has used FY-2 series of satellites to track movement of targets. Another possibility is launching many short duration, micro-Earth Observation satellites in times of conflict. It mentioned that China can launch a 100 kg satellite on 12 hours notice. In peace mission 05. They launched an experimental satellite on August 2nd for detection/science experiment work. This operated for 27 days and returned to earth on August 29th after the conclusion of the exercise.

Readers,

Please take this speculation with some serious salt...

Space Based Radar

A Bi-static GEO Space Radar would include a constellation of 3-4 GEO transmitters equipped with an L-band radar for airborne warning and control missions which would require a 100 m dish that would weigh 30,000 lbs and require 20+ kw of power. A Joint STARS-like radar in geosynchronous orbit would function in the S-band and would require a 25 m dish which would weigh 6,000 lbs and require 2 kw+ of power. The MEO receivers would include a constellation of 24-36 receivers at an altitude of 1600 km. For AWACS-like missions, the MEO satellites would require a 35 x 35 m array weighing 10,000 lbs. A Joint-STARS-like mission would require a 10 x 10 m receive array that would weigh 4,000 lbs.

The above example is just one of the many publicly available sources that contains reasonable details on the power requirements and antenna size of any long duration, meanings years, of space based radar systems, which of course would begs the question of what is the timespan of these speculative 'short duration micro satellites". But it is not speculative to reason that utility is proportionate to size and utility in this case mean time and power. So the smaller a 'micro satellite' that supposedly contains a radar, the smaller its antenna and therefore the less useful it will be, in terms of duration and detection capability. These 'micro satellites' could be in low orbit altitude and vulnerable to US ship based SM-3, as when we shot down US-193...

USA-193 - Wikipedia, the free encyclopedia

...an SM-3 missile to destroy the satellite, at an altitude of 130 nautical miles (240 km),...

So until we know the true operational orbit of these speculative 'micro satellites' the default position should be that the radar intelligence gap problem remain unsolved by China.

This ASBM system remains speculative, no matter how many times the original report is rehashed by different people, including US military leaders. The US DoD does not deny the technical feasibility but the generals and admirals are obliged to give the nation their 'worst case' scenarios. This is about regional access denial and the US military is not idle in creating means to maintain our access in time of war. Already in the subsystem level analysis, there are CURRENT defense mechanisms that WILL either render this speculative Chinese ASBM system useless or make it financially difficult for China to pursue. For example, over-the-horizon radar systems can be destroyed by B-2 bombers in concert with ship launched cruise missiles, creating a radar intelligence gap for this ASBM system. Would China launch several ASBMs against these smaller ships, thereby depleting stocks that could turn a favorable tide for China in a naval conflict against US? How would China defend these large OTH radar stations against sub launched cruise missiles?

 

[Martian2]

Readers,

Please take this speculation with some serious salt...

Space Based Radar

The above example is just one of the many publicly available sources that contains reasonable details on the power requirements and antenna size of any long duration, meanings years, of space based radar systems, which of course would begs the question of what is the timespan of these speculative 'short duration micro satellites". But it is not speculative to reason that utility is proportionate to size and utility in this case mean time and power. So the smaller a 'micro satellite' that supposedly contains a radar, the smaller its antenna and therefore the less useful it will be, in terms of duration and detection capability. These 'micro satellites' could be in low orbit altitude and vulnerable to US ship based SM-3, as when we shot down US-193...

USA-193 - Wikipedia, the free encyclopedia

So until we know the true operational orbit of these speculative 'micro satellites' the default position should be that the radar intelligence gap problem remain unsolved by China.

This ASBM system remains speculative, no matter how many times the original report is rehashed by different people, including US military leaders. The US DoD does not deny the technical feasibility but the generals and admirals are obliged to give the nation their 'worst case' scenarios. This is about regional access denial and the US military is not idle in creating means to maintain our access in time of war. Already in the subsystem level analysis, there are CURRENT defense mechanisms that WILL either render this speculative Chinese ASBM system useless or make it financially difficult for China to pursue. For example, over-the-horizon radar systems can be destroyed by B-2 bombers in concert with ship launched cruise missiles, creating a radar intelligence gap for this ASBM system. Would China launch several ASBMs against these smaller ships, thereby depleting stocks that could turn a favorable tide for China in a naval conflict against US? How would China defend these large OTH radar stations against sub launched cruise missiles?

If I were in China's position, my first step would be to launch many more reconnaissance satellites. I would place an even greater priority on developing stealth satellites to make them more survivable. Also, I would consider developing satellites with defensive capabilities (e.g. decoys, its own kinetic weapons, or laser for defense).

Another route that I would pursue is to develop long-range stealth UAVs. The goal is to gain targeting data on the carriers from sensors. It doesn't matter whether it's from a satellite or UAV.

As the article in the Wall Street Journal (i.e. WSJ) suggested, China may be able to acquire targeting data on carriers from underwater sensors, such as semi-buried underwater passive listening devices and/or through submarines.

Finally, the WSJ noted that anti-ship missiles themselves pose a significant danger to U.S. carriers. "In combination with antiship weapons launched from surface vessels, submarines, and aircraft, the missile barrage is designed to keep carrier battle groups beyond effective range." Just as in the case of ASBMs, only one anti-ship missile needs to penetrate U.S. defenses to cause significant damage. To understand the destructive power of a single anti-ship missile (e.g. French Exocet or Chinese "Exocet"/C-802), watch the video below. The dilemma remains the same. Is an admiral willing to risk capital ships in the belief of a 100% effective defense against swarms of Chinese anti-ship missiles and torpedoes?

Whether it's through ASBM and/or anti-ship weapons, as long as carrier battle groups are kept "beyond effective range," China has accomplished her strategic objective of delaying or negating the U.S. Navy's interference in a potential military conflict over the Taiwan Straits.

"ColdWarWarriors — January 13, 2009 — HMS Sheffield is sunk by an Argentinian Exocet missile in the Falklands war 1982."

"paradisedriver — August 01, 2008 — Training exercise video showing a "kill" in one shot."
[China's Yu-6 torpedo is the equivalent of an U.S. Mark-48 torpedo, which was used in the video.]

 

[gambit]

If I were in China's position, my first step would be to launch many more reconnaissance satellites. I would place an even greater priority on developing stealth satellites to make them more survivable. Also, I would consider developing satellites with defensive capabilities (e.g. decoys, its own kinetic weapons, or laser for defense).

Another route that I would pursue is to develop long-range stealth UAVs. The goal is to gain targeting data on the carriers from sensors. It doesn't matter whether it's from a satellite or UAV.

As the article in the Wall Street Journal (i.e. WSJ) suggested, China may be able to acquire targeting data on carriers from underwater sensors, such as semi-buried underwater passive listening devices and/or through submarines.

Finally, the WSJ noted that anti-ship missiles themselves pose a significant danger to U.S. carriers. "In combination with antiship weapons launched from surface vessels, submarines, and aircraft, the missile barrage is designed to keep carrier battle groups beyond effective range." Just as in the case of ASBMs, only one anti-ship missile needs to penetrate U.S. defenses to cause significant damage. To understand the destructive power of a single anti-ship missile (e.g. French Exocet or Chinese "Exocet"/C-802), watch the video below. The dilemma remains the same. Is an admiral willing to risk capital ships in the belief of a 100% effective defense against swarms of Chinese anti-ship missiles and torpedoes?

Whether it's through ASBM and/or anti-ship weapons, as long as carrier battle groups are kept "beyond effective range," China has accomplished her strategic objective of delaying or negating the U.S. Navy's interference in a potential military conflict over the Taiwan Straits.

Everything above is what I pointed out -- subsystems -- that are necessary, either as standalone system or in support of an ASBM system. For the former, we have proven countermeasures and if they are also necessary to support an ASBM system, their countermeasures would make it financially draining to develop and deploy an ASBM system. Your videos serves nothing more than to distract attention from what you cannot dispute.

 

[Martian2]

Everything above is what I pointed out -- subsystems -- that are necessary, either as standalone system or in support of an ASBM system. For the former, we have proven countermeasures and if they are also necessary to support an ASBM system, their countermeasures would make it financially draining to develop and deploy an ASBM system. Your videos serves nothing more than to distract attention from what you cannot dispute.

The strategy is to overwhelm the limited defense capabilities of a carrier group and to give them little time to react.

"If I were a Chinese general, I believe that I can sink the U.S. Navy if they come within range of my weapons.

I would use a combined attack. All attacks will be coordinated to arrive near-simultaneously at the target. I would designate a salvo of 50 ASBMs (i.e. anti-ship ballistic missiles) per carrier and 10 ASBMs per Aegis destroyer. I would simultaneously send swarms of CJ-10 cruise missiles at the U.S. ships. I would also deploy salvos of Chinese Exocets (i.e. C-802s). On the sea, I would send groups of "Type 022 (Houbei Class) Fast Attack Missile Crafts." Finally, I would also send swarms of attack submarines (i.e. Type 093 Shangs, Yuans, Songs, and Kilos) to fire Yu-6 (i.e. Mark 48-class) torpedoes at the U.S. ships.

If the U.S. Navy can survive a concentrated bombardment from space, air, sea-skimming missiles, and underwater torpedoes then they truly are the best in the world. If not, the U.S. Navy will be at the bottom of the Pacific Ocean. If the U.S. wants to bully China, they can expect China to hit the U.S. Navy with everything in the Chinese arsenal. The U.S. has never been tested by a massive combined attack. There is a good chance that the U.S. Navy will not survive."

I don't believe that you understand the point behind the article "China's Blitzkrieg on U.S. Carrier." I suggest that you reread the first few paragraphs. China's ASBM was merely an additional component to an already complex threat to U.S. Navy capital ships.

U.S. Navy capital ships faced threats from the air/cruise missiles, sea/sea-skimming Chinese "Exocets," and underwater/Yu-6 "Mark 48-class" torpedoes. China's ASBM added an extra dimension of an attack from space/ballistic missiles.

The U.S. Navy will have to take additional steps to try and neutralize China's ASBM system. Whether they will be successful, I don't know. Only an actual war can reveal which side was successful in executing their strategy.

China's ASBM is a mere component in a complex Chinese strategy of sea denial and/or delay of U.S. naval help for Taiwan. Pointing out a few weaknesses in China's existing ASBM sensor system does not lessen China's ability to wage blitzkrieg on U.S. carriers.

Finally, I will repeat the WSJ's point again. If China has placed significant numbers of underwater passive listening devices and they can triangulate the carrier's position from the sound of its propellers then the vulnerability of China's OTH radars is irrelevant.

 

[gambit]

I don't believe that you understand the point behind the article "China's Blitzkrieg on U.S. Carrier."

Yes I do.

I suggest that you reread the first few paragraphs. China's ASBM was merely an additional component to an already complex threat to U.S. Navy capital ships.

Currently, the PLAN does not have a 'complex' threat to a US aircraft carrier battlegroup.

U.S. Navy capital ships faced threats from the air/cruise missiles, sea/sea-skimming Chinese "Exocets," and underwater/Yu-6 "Mark 48-class" torpedoes. China's ASBM added an extra dimension of an attack from space/ballistic missile.

Low level sea cruise missiles have the same vulnerabilities as their over land cousins -- limited radar horizon. As long as the fleet has AWACS coverage, the cruise missile threat is not sufficient to deter the fleet. As for torpedoes, they are launched by submarines and the fleet does not sail without sub escorts. Again...Another threat, while not eliminated, is sufficiently degraded to where it does not offer a credible deterrence.

The U.S. Navy will have to take additional steps to try and neutralize China's ASBM system. Whether they will be successful, I don't know. Only an actual war can reveal which side was successful in executing their strategy.

One that China cannot afford to take the risk of losing. Iraq offered a more subtle lesson that the Chinese military leadership are more willing to admit than your clouded perception allowed you to see. Analysts the world over predicted tens of thousands allied casualties for Desert Storm. In the end, our troops were more afraid of 'frats' than we were of enemy fire. No matter how much contempt you may have for the Iraqi military, contempt cannot replace objective analyses. The fact is that China is at least one generation, more like two, overall behind US in power projection capabilities and how to bypass obstacles to that projection.

China's ASBM is a mere component in a complex Chinese strategy of sea denial and/or delay of U.S. naval help for Taiwan. Pointing out a few weaknesses in China's existing ASBM sensor system does not lessen China's ability to wage blitzkrieg on U.S. carriers.

Of course it does. Long range strikes ALWAYS depend on intelligence. The lower this range figure, the lower the efficacy index of said weapon system.

Finally, I will repeat the WSJ's point again. If China has placed significant numbers of underwater passive listening devices and they can triangulate the carrier's position from the sound of its propellers then the vulnerability of China's OTH radars is irrelevant.

If...??? How long into the future is this 'if'? Do you even know how sonar works and its vulnerabilities?

 

[Martian2]

Yes I do.


Currently, the PLAN does not have a 'complex' threat to a US aircraft carrier battlegroup.


Low level sea cruise missiles have the same vulnerabilities as their over land cousins -- limited radar horizon. As long as the fleet has AWACS coverage, the cruise missile threat is not sufficient to deter the fleet. As for torpedoes, they are launched by submarines and the fleet does not sail without sub escorts. Again...Another threat, while not eliminated, is sufficiently degraded to where it does not offer a credible deterrence.


One that China cannot afford to take the risk of losing. Iraq offered a more subtle lesson that the Chinese military leadership are more willing to admit than your clouded perception allowed you to see. Analysts the world over predicted tens of thousands allied casualties for Desert Storm. In the end, our troops were more afraid of 'frats' than we were of enemy fire. No matter how much contempt you may have for the Iraqi military, contempt cannot replace objective analyses. The fact is that China is at least one generation, more like two, overall behind US in power projection capabilities and how to bypass obstacles to that projection.


Of course it does. Long range strikes ALWAYS depend on intelligence. The lower this range figure, the lower the efficacy index of said weapon system.


If...??? How long into the future is this 'if'? Do you even know how sonar works and its vulnerabilities?

From almost every media source that I can find, including CBS News and the Wall Street Journal, the U.S. government and military take the threat seriously.

You are among the few die-hard skeptics who believe that China does not pose a serious/"complex" threat to an U.S. carrier group. That's your prerogative.

Blah blah blah about Iraq. Whatever.

The technology is 49 years old. It is silly to claim that China has not or cannot duplicate SOSUS in the waters off of China.

SOSUS - Wikipedia, the free encyclopedia

"SOSUS, an acronym for Sound Surveillance System, is a chain of underwater listening posts across the northern Atlantic Ocean near Greenland, Iceland and the United Kingdom — the GIUK gap. It was originally operated by the United States Navy for tracking Soviet submarines, which had to pass through the gap to attack targets further west. Other locations in the Atlantic and Pacific Ocean also had SOSUS stations. It was later supplemented by mobile assets such as the Surveillance Towed Array Sensor System (SURTASS), and became part of the Integrated Undersea Surveillance System (IUSS). Many other listening posts are still in operation around the world.
...

First SOSUS sensors

SOSUS goes operational

In 1961, SOSUS tracked the USS George Washington (SSBN-598) from the United States to the United Kingdom. The next year SOSUS detected and tracked its first Soviet diesel submarine. Later that year the SOSUS test system in the Bahamas tracked a Soviet Foxtrot class submarine during the Cuban Missile Crisis. SOSUS was upgraded a number of times as submarines became quieter.

SOSUS systems consisted of bottom mounted hydrophone arrays connected by underwater cables to facilities ashore. The individual arrays were installed primarily on continental slopes and seamounts at locations optimized for undistorted long range acoustic propagation. The combination of location within the ocean and the sensitivity of arrays allowed the system to detect acoustic power of less than a watt at ranges of several hundred kilometers."

China can build this:


Type 052C Aegis-class destroyer #171 Haikou


But not this???


A hydrophone

 

[Cityboy]

Great posts gambit. . Thanks for posting some physics and bursting yet again propaganda like photoshop jxx pics. .fanboys got their dose of reality

 

[below_freezing]

Great posts gambit. . Thanks for posting some physics and bursting yet again propaganda like photoshop jxx pics. .fanboys got their dose of reality

where's the physics?

i want to see some equations on here.

the only one that has offered a quantitative analysis is gpit. in physics, 1 number is worth 10 words.

 

[gambit]

where's the physics?

i want to see some equations on here.

the only one that has offered a quantitative analysis is gpit. in physics, 1 number is worth 10 words.

Yeah...The guy consistently refused to answer the most essential 15 words: Show me sources that say diffraction fields are irrelevant in RCS prediction and reduction techniques.

 

[gambit]

From almost every media source that I can find, including CBS News and the Wall Street Journal, the U.S. government and military take the threat seriously.

You are among the few die-hard skeptics who believe that China does not pose a serious/"complex" threat to an U.S. carrier group. That's your prerogative.

Of course we should. But nowhere does it mean we are in a 'panic' as the sensationalist headliners would like to portray US.

Blah blah blah about Iraq. Whatever.

Too bad for you the Chinese military leadership does not consider Iraq to be 'blah'.

The technology is 49 years old. It is silly to claim that China has not or cannot duplicate SOSUS in the waters off of China.

Where did I say China cannot copy SOSUS?

Anyway...SOSUS was successful against the older generation of sub, nuclear or else, that are much noisier than modern subs. Today, SOSUS has been relegated to civilian R/D efforts. Sonar detection degradation is far worse a problem than with radar detection. The density of the medium is the cause. What SOSUS did was to remember a particular acoustic signature and track its dislocation from one sensor post to the next. Because of issues like temperature variations, aka thermoclines, the next sensor post did not always detect that acoustic signature. So when the next sensor post does detect it, we now have a large geographical dislocation of said target.

The best weapon against a sub is still another sub, complemented by surface deployed sonar detection. Given how quiet are our nuclear subs, I do wish China great success in deploying a SOSUS-like system.

 

[Martian2]

Of course we should. But nowhere does it mean we are in a 'panic' as the sensationalist headliners would like to portray US.


Too bad for you the Chinese military leadership does not consider Iraq to be 'blah'.


Where did I say China cannot copy SOSUS?

Anyway...SOSUS was successful against the older generation of sub, nuclear or else, that are much noisier than modern subs. Today, SOSUS has been relegated to civilian R/D efforts. Sonar detection degradation is far worse a problem than with radar detection. The density of the medium is the cause. What SOSUS did was to remember a particular acoustic signature and track its dislocation from one sensor post to the next. Because of issues like temperature variations, aka thermoclines, the next sensor post did not always detect that acoustic signature. So when the next sensor post does detect it, we now have a large geographical dislocation of said target.

The best weapon against a sub is still another sub, complemented by surface deployed sonar detection. Given how quiet are our nuclear subs, I do wish China great success in deploying a SOSUS-like system.

Fact 1: Giant carrier propeller generates huge amount of energy.



Fact 2: A SOSUS-like system can "detect acoustic power of less than a watt at ranges of several hundred kilometers." The carrier propeller is generating an unimaginably greater amount of energy "than a watt." For comparison, the light bulb in your room is probably 100 watts. 100 watts cannot spin a carrier propeller.

http://en.wikipedia.org/wiki/SOSUS

"SOSUS systems consisted of bottom mounted hydrophone arrays connected by underwater cables to facilities ashore. The individual arrays were installed primarily on continental slopes and seamounts at locations optimized for undistorted long range acoustic propagation. The combination of location within the ocean and the sensitivity of arrays allowed the system to detect acoustic power of less than a watt at ranges of several hundred kilometers."

Fact 3: Using the data from a SOSUS-like system, the location of an aircraft carrier can be determined through acoustic location. "Multiple passive sonars can be used for range localization by triangulation or correlation, directly."

Acoustic location - Wikipedia, the free encyclopedia

"Sonar

SONAR (SOund Navigation And Ranging) — or sonar — is a technique that uses sound propagation under water (or occasionally in air) to navigate, communicate or to detect other vessels. There are two kinds of sonar — active and passive. A single active sonar can localize in range and bearing as well as measuring radial speed. However, a single passive sonar can only localize in bearing directly, though target motion analysis can be used to localize in range, given time. Multiple passive sonars can be used for range localization by triangulation or correlation, directly."

Final step: Transmit the data for the location of the carrier to China's ASBMs. ASBMs will be raining down on the carrier group.

 

[gambit]

Fact 1: Giant carrier propeller generates huge amount of energy.

Fact 2: A SOSUS-like system can "detect acoustic power of less than a watt at ranges of several hundred kilometers." The carrier propeller is generating an unimaginably greater amount of energy "than a watt." For comparison, the light bulb in your room is probably 100 watts. 100 watts cannot spin a carrier propeller.

I cannot help but chuckle at the highlighted above. I have to save this. You are saying that power generated, an output, is the exact same level as input. You are saying that the nuclear reactor of a Nimitz class carrier output is 190Mw so the power level of the sonar signature is the same level: '100 watts cannot spin a carrier propeller'.

What I see are not facts but comical attempts at making up 'facts' and the continuation of violations of the laws of physics to support said made up 'facts'.

One hundred watts cannot rotate an aircraft carrier's propeller. A Nimitz class nuclear reactor generate 190Mw. Therefore, the sonar signature of the screws must be 190Mw, or somewhere around that level. May be am missing something in the translation here.

Anyway...A surface ship's sonar detection is based upon mechanically generated noises and cavitation flow. SOSUS or a SOSUS-like sensor system would have no problems picking up any surface noises such as those generated by ships. But SOSUS was created mainly to detect the low freqs screw noises generated by subs and we are talking about deterring an aircraft carrier fleet to at least one thousand km out, not several hundreds as that distance is within strike range. So what good is this sensor net if it cannot provide target information beyond one thousand km?

Oh...Of course...The ship's screws are generating 190Mw of underwater noise power level...!!!

SOFAR channel - Wikipedia, the free encyclopedia

The SOFAR channel (short for Sound Fixing and Ranging channel), or deep sound channel (DSC),[1] is a horizontal layer of water in the ocean at the depth at which the speed of sound is minimal. The SOFAR channel acts as a waveguide for sound, and low frequency sound waves within the channel may travel thousands of miles before dissipating.[2] This phenomenon is an important factor in submarine warfare.

SOSUS sensors were positioned deep enough to exploit this underwater feature -- deep sound channels. But for a surface noise generator, there is something called a 'shadow zone' in sonar detection...

SOFAR channel - Wikipedia, the free encyclopedia

In underwater acoustics, a region in which very little sound energy penetrates, depending upon the strength of the lower boundary of the surface duct. It is usually bounded by the lower boundary of the surface duct and the limiting ray. There are two shadow zones: the sea surface, beneath which a shadow is cast by the surface in the sound field of a shallow source, and the deep-sea bottom, which produces a shadow zone in the upward-refracting water above it.

The sub is a passive sensor. Its current depth would not give it very accurate surface location of that surface noise generator -- the ship. Range equation states that power density decreases with distance. But in dealing with thermoclines, sonar detection is often restricted to two dimensions. That is why SOSUS was successful during the Cold War against subs because subs NEEDS to go deep. Sea water density increases with depth. EM wave speed decreases in thick medium, like water. On the other hand, sound wave speed INCREASES in the same thick medium. But sound waves also BENDS as they travels through different density layers. The refraction effect gets more pronounced with increasing sound wave speed and density levels. Depth is the sub's protection against detection but because of the shadow zones, depth also limit or can even prevent the sub from detecting surface noise generators -- ships.

So if China intends to deploy passive sensors against surface ships, the net will not be far off shore, thereby limiting its effective detection range to within several hundreds km, within the carrier's air wing strike distance. As the illustration shows, there would be multiple sonar echoes created by the water surface, generating multiple locations of the same ship. The sun will create temperature gradients well below the ship's hull. Add in salinity. The result is called 'anomalous propagations due to acoustic refractions'.

Refraction - Wikipedia, the free encyclopedia

In underwater acoustics, refraction is the bending or curving of a sound ray that results when the ray passes through a sound speed gradient from a region of one sound speed to a region of a different speed. The amount of ray bending is dependent upon the amount of difference between sound speeds, that is, the variation in temperature, salinity, and pressure of the water.

It is only in your dream that a SOSUS-like sensor net can provide sufficient target information -- to a single ship -- for an ASBM system. The problem here is that you and fanboys like you eagerly grasp on to the most general information put out by other fanboys or by popular media not interested in details in the ones I pointed out above. SOSUS was not perfect and we never claimed it to be. SOSUS did not 'track' any target in the popular context of the word. SOSUS was successful because the Soviets were technologically inferior to US. But in this case, China would be replicating something we retired. We created it, we know how to defeat it or reduce its efficacy.

 

[Martian2]

I cannot help but chuckle at the highlighted above. I have to save this. You are saying that power generated, an output, is the exact same level as input. You are saying that the nuclear reactor of a Nimitz class carrier output is 190Mw so the power level of the sonar signature is the same level: '100 watts cannot spin a carrier propeller'.

What I see are not facts but comical attempts at making up 'facts' and the continuation of violations of the laws of physics to support said made up 'facts'.

One hundred watts cannot rotate an aircraft carrier's propeller. A Nimitz class nuclear reactor generate 190Mw. Therefore, the sonar signature of the screws must be 190Mw, or somewhere around that level. May be am missing something in the translation here.

Anyway...A surface ship's sonar detection is based upon mechanically generated noises and cavitation flow. SOSUS or a SOSUS-like sensor system would have no problems picking up any surface noises such as those generated by ships. But SOSUS was created mainly to detect the low freqs screw noises generated by subs and we are talking about deterring an aircraft carrier fleet to at least one thousand km out, not several hundreds as that distance is within strike range. So what good is this sensor net if it cannot provide target information beyond one thousand km?

Oh...Of course...The ship's screws are generating 190Mw of underwater noise power level...!!!

SOFAR channel - Wikipedia, the free encyclopedia

SOSUS sensors were positioned deep enough to exploit this underwater feature -- deep sound channels. But for a surface noise generator, there is something called a 'shadow zone' in sonar detection...

SOFAR channel - Wikipedia, the free encyclopedia




The sub is a passive sensor. Its current depth would not give it very accurate surface location of that surface noise generator -- the ship. Range equation states that power density decreases with distance. But in dealing with thermoclines, sonar detection is often restricted to two dimensions. That is why SOSUS was successful during the Cold War against subs because subs NEEDS to go deep. Sea water density increases with depth. EM wave speed decreases in thick medium, like water. On the other hand, sound wave speed INCREASES in the same thick medium. But sound waves also BENDS as they travels through different density layers. The refraction effect gets more pronounced with increasing sound wave speed and density levels. Depth is the sub's protection against detection but because of the shadow zones, depth also limit or can even prevent the sub from detecting surface noise generators -- ships.

So if China intends to deploy passive sensors against surface ships, the net will not be far off shore, thereby limiting its effective detection range to within several hundreds km, within the carrier's air wing strike distance. As the illustration shows, there would be multiple sonar echoes created by the water surface, generating multiple locations of the same ship. The sun will create temperature gradients well below the ship's hull. Add in salinity. The result is called 'anomalous propagations due to acoustic refractions'.

Refraction - Wikipedia, the free encyclopedia

It is only in your dream that a SOSUS-like sensor net can provide sufficient target information -- to a single ship -- for an ASBM system. The problem here is that you and fanboys like you eagerly grasp on to the most general information put out by other fanboys or by popular media not interested in details in the ones I pointed out above. SOSUS was not perfect and we never claimed it to be. SOSUS did not 'track' any target in the popular context of the word. SOSUS was successful because the Soviets were technologically inferior to US. But in this case, China would be replicating something we retired. We created it, we know how to defeat it or reduce its efficacy.

You seem to have a problem in understanding a very simple concept. Let's try this again.

Just like in SOSUS, China's hydrophones will be located near the continental shelf. "The individual arrays were installed primarily on continental slopes and seamounts at locations optimized for undistorted long range acoustic propagation." (see SOSUS - Wikipedia, the free encyclopedia)

Fact 1: Location of China's hydrophones are already roughly 350 Km out to sea (e.g. equivalent to 210 miles; if you use nautical miles then the distance is pushed out a little further).

The Delimitation of East China Sea Continental Shelf£ºSino-Japanese Disputes from the Perspective of International Law

"The continental shelf between China and Japan is 325 nautical miles in width at maximum, 167 nautical miles at minimum and 216 nautical miles in average, ..."

Fact 2: SOSUS-like system can "detect acoustic power of less than a watt at ranges of several hundred kilometers."

Putting facts (1) + (2) together, this means that if a carrier propeller generated less than a watt of acoustic energy then China's SOSUS-like system can detect an aircraft carrier out to 650 Km or more.

Math: Hydrophones are located 350 Km from coast on continental shelf + several hundred kilometers (e.g. 300 Km or more) = ballpark 650 Km range.

Fact 3: Giant carrier propellers generate an enormous amount of acoustic energy as they spin and push a 100,000 ton aircraft carrier through the water. An extremely conservative detection range of the carrier's propellers is at least 950Km or roughly 1,000 Km.

Hydrophones can detect the acoustic energy of giant carrier propellers at distances far in excess of a mere "several hundred kilometers." Despite the incredibly noisy carrier propellers, we'll be extremely conservative and add a mere 300 Km to the hydrophones' existing detection range. In reality, the hydrophones' detection range will be far in excess of 300 Km because the acoustic energy level jumped from "less than a watt" to "something really huge."

Fact 4: The acoustic data from the hydrophones are "undistorted." SOSUS-like hydrophones are intentionally placed at "seamounts at locations optimized for undistorted long range acoustic propagation." (see SOSUS - Wikipedia, the free encyclopedia)

Fact 5: Combine the acoustic data from China's SOSUS-like system and use "acoustic location" and triangulation to determine location of carrier (see Acoustic location - Wikipedia, the free encyclopedia).

Final step: Transmit the data for the location of the carrier to China's ASBMs. ASBMs will be raining down on the carrier group.

Is this clear enough for everyone? Or are some of you still confused?

[Note: A quick comment on the level of the carrier propellers' acoustic energy. I use a description like "something really huge" because I don't know the exact figure. Also, the figure will change depending on the speed of rotation of the propeller.

Knowing that a Nimitz carrier has two reactors that can each generate up to 190 MW doesn't get me very far. What proportion is used for onboard electrical use and what proportion is directed to the four bronze propellers? Does anyone also happen to know the "loss" rate in mechanical energy transmission? Just like the powertrain in your car, energy is wasted in the transmission system and driveshaft.

Next, does anyone know what proportion of the propeller's energy is consumed by productive kinetic energy conversion and what proportion is converted into acoustic energy? I don't know the answer to that question either.

Finally, I don't think that it's important to become obsessed over what I consider to be an unimportant minor detail. Take one look at the wake of an aircraft carrier and you can tell that a "really huge" amount of acoustic energy is helping to make those bubbles. Common sense should indicate that China can probably locate the aircraft carrier a lot further than 1,000 Km.]

 

[gambit]

You seem to have a problem in understanding a very simple concept.

And you are no different than the other Chinese fanboys here who simply repeat the same arguments when faced with details that they cannot dispute. Long range acoustics is best when the sensor is at a certain depth to exploit 'deep sound channels', but that same depth would place the sensor in the 'shadow zones' where thermoclines can render surface noise generators unreliable as to their precise surface locations. Above the 'shadow zones' we have anomalous propagations caused by surface reflections and the same temperature and density gradients. If things are as easy as you try to fool people here, then why bother with sonar school anyway?

 

[Martian2]

And you are no different than the other Chinese fanboys here who simply repeat the same arguments when faced with details that they cannot dispute. Long range acoustics is best when the sensor is at a certain depth to exploit 'deep sound channels', but that same depth would place the sensor in the 'shadow zones' where thermoclines can render surface noise generators unreliable as to their precise surface locations. Above the 'shadow zones' we have anomalous propagations caused by surface reflections and the same temperature and density gradients. If things are as easy as you try to fool people here, then why bother with sonar school anyway?

Take a look at the picture of the continental shelf. Arrays of hydrophones can be placed in water that is no deeper than 100m to avoid thermoclines. Or, if you're willing to spend the money, a country can place arrays of hydrophones at different depths along the continental slope. This approach would be similar to the placement of hydrophones at different depths by a group of U.S. destroyers with their towed array detectors.

To repeat, for those who do not understand, water that is 100m or less form essentially one layer. Arrays of hydrophones in 100m or less can avoid a thermocline and easily detect the sound of an aircraft carrier propeller.

I never claimed that it was easy. However, the physics is pretty straightforward. China has the sicentists, technology, money, and computer processing power to utilize a 49 year-old technology to find a "really huge" carrier propeller acoustic source. Why is that a big deal? It's a lot easier than building a sophisticated Aegis-class destroyer, which is NOT a 49 year-old technology.

Thermocline - Wikipedia, the free encyclopedia

"Waves mix the water near the surface layer and distribute heat to deeper water, such that the temperature may be relatively uniform for up to 100 m (300 ft), depending on wave strength and the existence of surface turbulence caused by currents. Below this mixed layer, however, the temperature remains relatively stable over day/night cycles. The temperature of the deep ocean drops gradually with depth."


"Graph showing a tropical ocean thermocline (depth vs. temperature). Note the rapid change between 100 and 200 meters."