What It Would Really Take To Sink a modern Aircraft Carrier

[The Accountant]

I am not saying China can only have 1 transport launcher shooting at a carrier at one time, but how many tracker you can place to shoot at one point of location? In mathematically sense, the target is at tangent to the range of the missile. How many launcher can you place at different location so they all overlap the same target?

From mathematics, the longer the distance between the target and the DF-21D launcher, the less overlapping it can have, meaning at maximum range, if it was deployed along the coast at the straight line, there are only 1 overlapping to the target (As there can only be one point you can draw a line between the target and the launcher), the closer the target get, the more overlapping.

As I said, I was saying if the Carrier is far away from the coast, that mean the distance will be at maximum range.

SM-3 Block 3 are GPS aided mid-course, where the launch ship feed data to the missisle and the last stage turn in onboard active LWIR seeker

so unless you are saing the AGEIS system can only track one or two target at a time, whatever you read is wrong



manoeuvrable is not the same aspurely fast speed.

What you said is akin to something like this.

Since a TOW Missile can be wired guided and a lot quicker than me, I cannot escape the TOW missile because if it changed by a small degree, the course it alter will be huge. In fact, course change in a high velocity object is not optimum. Because A.) The aim will be throw off. And B.) Because of the speed, you cannot correct the trajectory.

Say you aim a missile at me, I can run left, right and stop if you fire when I run right, and you alter the course so the missile alter to the right and the target stopped, stopping at 32 knots is easy (well, not easy actually, but correcting a missile when you are going 10 Mach is hard. meaning you need to stop swing right and swing back to the left to follow me. All in the while you only get a few second to do that

I think China has pratcied to launch multiple cruise ballistic missiles simultaneously from same location ... I have seen the videos so basis of my argument is based on this assumption ... (assumptions can always be right or wrong)

The only problem is, Fighter Bomber can be refuelled, be it Buddy refuel or refuelled by tanker. Like this



Operation Blackbuck see British Bomber refuelled 7 times to bomb Argentinian force in Falkland Island, and it have a round trip of 14,000 mile. DF missile series have a range of 2000-4000 Km.

Fighter will still be able to touch those missile even if they are out of range.

View attachment 392920

Missiles follow proportional navigation. They don't follow the target. Against a mach 10 missile, a 32 knot large ship hasn't really moved.



The first thing is, DF-series is not a OTH missile, it have to go up in the atmosphere and perform the terminal guidance, it does not shoot like a normal ground to ground missile

Secondly, you forgot the operational delay coming from the Missile Guidance to the Target, before terminal guidance kick in, target information have to feed into the missile by other means, and for China to locate the carrier, you will need to have real time surveillance on target. Each second the target information did not update would mean the missile can be travelling on a wrong direction.

Also, you are using the extreme close range as an example, really doubt the carrier will intentionally go within 100 km (60 miles) within Chinese coast when their bomber can reach at least 1000 mile without refuelling.

Bombers will unlikely to give any real advantage to China in current scenario as China also have capable fighting force and with satellites they monitor every move on career deck so there will be no surprise and ofz China will have superiority ... (assuming there is no F35, F22, J20 or J31 in the game) ...

 

[randomradio]

The only problem is, Fighter Bomber can be refuelled, be it Buddy refuel or refuelled by tanker. Like this



Operation Blackbuck see British Bomber refuelled 7 times to bomb Argentinian force in Falkland Island, and it have a round trip of 14,000 mile. DF missile series have a range of 2000-4000 Km.

Fighter will still be able to touch those missile even if they are out of range.

At 2000-4000Km, it will be worse than Battle of Britain, and completely against your favour.

Your tanking operations will be too small and won't survive. Not to mention Chinese jets will have more numbers, more range, more tanker support, AWACS support, satellite support, SAM support etc. While the American squadrons may likely have none of that, while a portion of the fleet will end up being used as tankers.

The Chinese are closing the capability gap.

The first thing is, DF-series is not a OTH missile, it have to go up in the atmosphere and perform the terminal guidance, it does not shoot like a normal ground to ground missile

Secondly, you forgot the operational delay coming from the Missile Guidance to the Target, before terminal guidance kick in, target information have to feed into the missile by other means, and for China to locate the carrier, you will need to have real time surveillance on target. Each second the target information did not update would mean the missile can be travelling on a wrong direction.

You will be surprised how capable China is at this.

Check out 0:48

http://www.popsci.com/gaofen-4-worl...s-chinas-great-leap-forward-into-space#page-3
In the Gaofen 4's case, its range of view is a 7,000km by 7,000km box of 49 million square kilometers of Asian land and water in and around China.

The Gaofen 4 is the world's most powerful GEO spy satellite. It has a color image resolution of slightly less than 50 meters (which is enough to track aircraft carriers by their wake at sea) and a thermal imaging resolution of 400m (good for spotting forest fires). It may also have a lower resolution video streaming capacity.

By 2030, the Jilin constellation will have 138 imaging, high-resolution small satellites that provide all weather coverage of any point on Earth, at 10 minute intervals.

And this is stuff that's open source.

Let's not forget that the DF-21D's flight time is not going to be more than 10 min. So the carrier, even at full speed, will not have covered more than 10Km. That kind of distance is not such a big problem for a radar and/or IIR seeker. As mentioned earlier, maneuverability won't do anything here.

Also, you are using the extreme close range as an example, really doubt the carrier will intentionally go within 100 km (60 miles) within Chinese coast when their bomber can reach at least 1000 mile without refuelling.

No, I'm talking about when the warhead becomes a real threat and easily detectable by a ship. Plus I've considered the warhead to be highly capable. The Aegis should be able to track the BM once it's above radar horizon, that won't change.

 

[jhungary]

At 2000-4000Km, it will be worse than Battle of Britain, and completely against your favour.

Your tanking operations will be too small and won't survive. Not to mention Chinese jets will have more numbers, more range, more tanker support, AWACS support, satellite support, SAM support etc. While the American squadrons may likely have none of that, while a portion of the fleet will end up being used as tankers.

The Chinese are closing the capability gap.

Wrong, Chinese jet only have more number and more range if they are close to the coast. If the war is far from the coast (2000-4000km is far from the coast) their number and strength will be nullified by the distant cover. SAM does not goes 2000-4000km outside the coast, unless you put them at sea.

And Battle of Britain does not have aerial refuelling involved. I am talking about Operation Black Buck, which is a surgical strike from Ascension to Falkland Island, using a Vulcan bomber that have 1600 km range on a 8000 km strike.

You will be surprised how capable China is at this.

Check out 0:48

http://www.popsci.com/gaofen-4-worl...s-chinas-great-leap-forward-into-space#page-3
In the Gaofen 4's case, its range of view is a 7,000km by 7,000km box of 49 million square kilometers of Asian land and water in and around China.

The Gaofen 4 is the world's most powerful GEO spy satellite. It has a color image resolution of slightly less than 50 meters (which is enough to track aircraft carriers by their wake at sea) and a thermal imaging resolution of 400m (good for spotting forest fires). It may also have a lower resolution video streaming capacity.

By 2030, the Jilin constellation will have 138 imaging, high-resolution small satellites that provide all weather coverage of any point on Earth, at 10 minute intervals.

And this is stuff that's open source.

Let's not forget that the DF-21D's flight time is not going to be more than 10 min. So the carrier, even at full speed, will not have covered more than 10Km. That kind of distance is not such a big problem for a radar and/or IIR seeker. As mentioned earlier, maneuverability won't do anything here.

explained before, this is not how Satellite work.

I can pick up something on my monitor does not mean I can know its position real time.

read this

https://defence.pk/pdf/threads/chin...oups-real-time-position-every-30-mins.479064/

If you have not used satellite image for war you would not know, in reality, satellite cannot track a target in real time given the operational delay. Simply because

1.) Satellite cannot recognize what is an aircraft carrier
2.) Satellite cannot pick up a signal and predict which way the target is going.
3.) It take time to process information.

In this field, when we are using satellite int (SATINT), we always said this intel is valid as of something something, in Chinese term, that time frame is 30 minutes.

Geofan-4 cannot used to track moving target, first, you need to point the satellite in the direction where the carrier is. Without ground radar, it's hard to do.

Then even if you able to put the SAT on top of the carrier, the satellite itself will not know what is a carrier, for them , it's pixel, and it would require a human eyes to see if that is a cargo ship, cruise liner or an aircraft Carrier. Then if you tag the target, the satellite will need to refresh, and it would be next cycle before you can process the image, by then the carrier would already be 10s of miles away, and you will need to restart the process.

No, I'm talking about when the warhead becomes a real threat and easily detectable by a ship. Plus I've considered the warhead to be highly capable. The Aegis should be able to track the BM once it's above radar horizon, that won't change.

again, missile go upward, not over the horizon.

The moment the missile goes up, that is when the AEGIS missile defence start working, and just because the missile went into stratosphere, that does not mean AEGIS stop tracking. Meaning the moment the Missile come back down to earth, it is at that moment the AEGIS intercept once they are in the operational range. and that could still be thousand of kilometre away.

I think China has pratcied to launch multiple cruise ballistic missiles simultaneously from same location ... I have seen the videos so basis of my argument is based on this assumption ... (assumptions can always be right or wrong)

Again, you can of course shoot multiple missile at different spot, but can they be overlapping a target?

You seems to not understanding what I said. You draw a circle, that represent the range of a DF series launcher, and at the rim, pick a spot and draw a dot, that is the carrier location.

Now along the line perpendicular between the missile launcher (Denoted the coast) and target draw another circle somewhere else with the centre along the same line representing another DF launcher, that circle will never touch that dot due to the mathematical properties. denoting that the second circle (The launcher), no matter how or where you draw it, will be out of range of the Carrier.

Now, move the dot (carrier), a bit closer to the centre of the first circle, now if you draw the second circle, the dot will be within the overlapping circle. Which mean both launcher is within range. And the closer the dot (Carrier) get, the more circle you can overlap the target.

The further out the target from the closet launcher, the less launcher you can put to overlap the target and keep all of the launcher within range, at the maximum distant, that can only be one.

Bombers will unlikely to give any real advantage to China in current scenario as China also have capable fighting force and with satellites they monitor every move on career deck so there will be no surprise and ofz China will have superiority ... (assuming there is no F35, F22, J20 or J31 in the game) ...

The problem is that, Again, I assume the carrier is in open ocean, far from Chinese costal support and Chinese Air and Sea borne AWACS is still at their infancy, they could not pick up a strike and direct it in a timely fashion outside the territorial radar coverage.

 

[Basel]

To sink an air ship carrier first you need to know where to hit the carrier to get it sink. Air ship carriers use extensive weight management and if you hit the area which if damaged will shift air ship carriers weight will sink it. In case of Indian carriers the weight is usually balanced between Fuel load and Aircraft load so taking out the fuel load side will make the carrier out of balance and thus can sink with a rather smaller pay load.

Now lets move to counter measures. You need a missile that is capable of making a low altitude fight. A missile that uses both RADAR and Anti Radiation homing. The missile needs to be sub sonic beyond horizon Super sonic after horizon. The missile needs to have a RDD design and it will be a single shot kill.

To sink ships in WW-2 most effective way was to hit torpedoes on one side of ships so water can enter from one side and capsize ship quickly and it is still effective against any ship if its defenses can be breached.

Edit.

This is how huge ships capsize and sink with torpedo hit.

 

[randomradio]

Wrong, Chinese jet only have more number and more range if they are close to the coast. If the war is far from the coast (2000-4000km is far from the coast) their number and strength will be nullified by the distant cover. SAM does not goes 2000-4000km outside the coast, unless you put them at sea.

Why will the war happen far from Chinese coast?

You have to go to the Chinese. The war zone is Korea, Taiwan, SCS, Japan etc. All within 500-1000Km.

While the Chinese will be freely flying all their jets within that airspace, your side will be struggling to just make it to the fight. All because of a carrier killing ballistic missile.

And Battle of Britain does not have aerial refuelling involved. I am talking about Operation Black Buck, which is a surgical strike from Ascension to Falkland Island, using a Vulcan bomber that have 1600 km range on a 8000 km strike.

How many sorties can you mange? How many jets can you bring in that way? How many tankers can survive?

You forget that the Flankers have more range and are capable of buddy refueling also.

explained before, this is not how Satellite work.

I can pick up something on my monitor does not mean I can know its position real time.

They can calculate the real time position of the target down to centimeters with the method I posted above.

It's simple geometry. They know the position of the satellite, they know the exact position of the ground they are looking at. They know the angle the satellite is at to the ground.

Every time the camera changes its viewing angle, the position on the ground changes, that's how the target's location is captured. The rest depends on the warhead's seeker.

read this

https://defence.pk/pdf/threads/chin...oups-real-time-position-every-30-mins.479064/

Will do.

If you have not used satellite image for war you would not know, in reality, satellite cannot track a target in real time given the operational delay. Simply because

1.) Satellite cannot recognize what is an aircraft carrier

Bro, are we going back to this? I told you, target detection and identification has become automated. The satellite can easily recognize even a tree, even a park bench. Detecting and recognizing a carrier is very easy, without human intervention.

Of course, it's not the satellite that does the detection, it is the ground control that does it, using real time processing.

2.) Satellite cannot pick up a signal and predict which way the target is going.

Yes it can. A satellite can pick up even the wake of fishing trawlers.

http://spo.nmfs.noaa.gov/mfr391/mfr3913.pdf
Q. Does LANDSAT detect fish?
A. No, its resolution (ability to detect objects like fish schools) is inadequate. There are no civilian satellites available with adequate resolution to detect most fish schools (e.g., menhaden and thread herring). An object has to be about 80 m in diameter and very contrasting in color before LANDSAT can detect it.

Do you see how old this technology is? But even then it requires an object to be 80m long. Now, even civilian satellites can see individual trees and park benches.

3.) It take time to process information.

How about I tell you it's real time. I'll get you real time tracking data soon, gimme a minute. I'll post a video after I read the link you gave.

again, missile go upward, not over the horizon.

I was talking about the ship radar picking up the missile once the BM crosses the radar horizon of the ship's radar.

The moment the missile goes up, that is when the AEGIS missile defence start working, and just because the missile went into stratosphere, that does not mean AEGIS stop tracking. Meaning the moment the Missile come back down to earth, it is at that moment the AEGIS intercept once they are in the operational range. and that could still be thousand of kilometre away.

Yes, I don't disagree that the radar cannot track the BM. All I said is, once the missile breaks through radar horizon, it will be tracked throughout its flight path. Advantage Aegis.

But I'm more interested in what's inside the nose of the BM. The warhead is what makes the DF-21D deadly, everything else is no different from a regular BM.

Anyway, laser BMD is the future for long range interception and area defence and rail gun is the future for CIWS type point defence against hypersonic targets. Missiles are not useful beyond a certain point due to speed and time limitations. That's why the warheads are gaining more prominence. Pretty soon SAMs are not going to be very useful against such 'warheads'. Especially hypersonic warheads that have flat trajectories, something the DF-21D is likely to possess.

 

[jhungary]

Why will the war happen far from Chinese coast?

You have to go to the Chinese. The war zone is Korea, Taiwan, SCS, Japan etc. All within 500-1000Km.

While the Chinese will be freely flying all their jets within that airspace, your side will be struggling to just make it to the fight. All because of a carrier killing ballistic missile.

Why will the war far from the Chinese Coast? If that was near, in South Korea, Taiwan, and Japan, then why not just use the airfield in Korea, Taiwan and SCS.

Again, why would US uses Carrier close to Chinese Coast at all, if the battlefield is Japan, Korea or SCS.

How many sorties can you mange? How many jets can you bring in that way? How many tankers can survive?

You forget that the Flankers have more range and are capable of buddy refueling also.

It works both way. Only China have less air refuelling asset in theatre, Meaning Chinese sorties will be drastically limited if a war is in open ocean.

In case of a war happening close to home, Between 7 US Airbases in Japan, 2 US bases in Korea, 1 US base in the Pacific, home to 2 Carrier Air Wing (Each CAW have 4 naval fighter squadron, which is 48 fighter each) and 7 Fighter wings (about 500 fighters. Each wing have 3 squadron, each squadron have 24 fighters) With addition deployment in Marine Air Station (3 Squadrons in each of the 3 stations MCAS Futenma, Iwakuni and Atsugi) Which give another 50 fighters.

China have 210 J-11, 75 Su-30, 75 Su-27 and 24 Su-35

They can calculate the real time position of the target down to centimeters with the method I posted above.

It's simple geometry. They know the position of the satellite, they know the exact position of the ground they are looking at. They know the angle the satellite is at to the ground.

Every time the camera changes its viewing angle, the position on the ground changes, that's how the target's location is captured. The rest depends on the warhead's seeker.

They can't, first, your satellite need to know what they are looking at, and give a reference point. That mean you need to look at the image yourself and tag the target from the image and allowing the computer to track the target for you.

However, while you are doing that, the satellite will "refresh" and they will prepare the next image. And the next one, and the next one. Meaning you can never do the target acquisition in real time.

Computer power is great today, it is not that advance the computer can distinguish target from different angle. Even if you make a 3D model, the model may not be accurate because there are no way to make an accurate 3d model unless you use a laser and scan the actual carrier in all dimension...

Will do.



Bro, are we going back to this? I told you, target detection and identification has become automated. The satellite can easily recognize even a tree, even a park bench. Detecting and recognizing a carrier is very easy, without human intervention.

Of course, it's not the satellite that does the detection, it is the ground control that does it, using real time processing.

How? Do explain to me what kind of algorithm currently exist that allow AI identification of a 3-D object in a 2-D image.

It's not just by you saying "It can be done" If it can be done, then there must be a way, show me how it can be done and I will agree with you, otherwise for all my military knowledge and computer science knowledge (I have a graduation diploma in Computer Science) I have not known that there exist an algorithm that can run automatic image recognition of a 3-D object to 2-D

Yes it can. A satellite can pick up even the wake of fishing trawlers.

http://spo.nmfs.noaa.gov/mfr391/mfr3913.pdf
Q. Does LANDSAT detect fish?
A. No, its resolution (ability to detect objects like fish schools) is inadequate. There are no civilian satellites available with adequate resolution to detect most fish schools (e.g., menhaden and thread herring). An object has to be about 80 m in diameter and very contrasting in color before LANDSAT can detect it.

Do you see how old this technology is? But even then it requires an object to be 80m long. Now, even civilian satellites can see individual trees and park benches.

It wasn't even what this guy say.

Does Landsat detect fish, it can detect fish. You can see parks and trees on a computer does not mean the computer itself recognize it as parks and trees. It can recognize shape, as in polygon, but it's a far cry from that to say My computer can identify that is a tree in that image.

Again, show me any one of the algorithm that can did that, otherwise I will have to say you are dreaming.

How about I tell you it's real time. I'll get you real time tracking data soon, gimme a minute. I'll post a video after I read the link you gave.

The post said Chinese satellite can update a target within 30 minutes, 30 minutes is not real time. the Article itself said it cannot be done in real time.

I was talking about the ship radar picking up the missile once the BM crosses the radar horizon of the ship's radar.

I was talking about the starting point, Tracking was not start when the missile come down, it started when the missile goes up.

Yes, I don't disagree that the radar cannot track the BM. All I said is, once the missile breaks through radar horizon, it will be tracked throughout its flight path. Advantage Aegis.

But I'm more interested in what's inside the nose of the BM. The warhead is what makes the DF-21D deadly, everything else is no different from a regular BM.

Anyway, laser BMD is the future for long range interception and area defence and rail gun is the future for CIWS type point defence against hypersonic targets. Missiles are not useful beyond a certain point due to speed and time limitations. That's why the warheads are gaining more prominence. Pretty soon SAMs are not going to be very useful against such 'warheads'. Especially hypersonic warheads that have flat trajectories, something the DF-21D is likely to possess.

So you are basing this on something you don't know and it's not even in reality? Oh well...

If you want to talk about in the future, what make you think in the future, SAM technology will not advance and have a way or ways to deal with hypersonic warhead??

The point is, you don't know what China and US is working on at the moment, maybe they already have an answer for Hypersonic weapon, you don't know that, even I have TS/SCI clearance and I don't know that, you cannot justify what will happen today by looking into the future.

 

[randomradio]

Why will the war far from the Chinese Coast? If that was near, in South Korea, Taiwan, and Japan, then why not just use the airfield in Korea, Taiwan and SCS.

Again, why would US uses Carrier close to Chinese Coast at all, if the battlefield is Japan, Korea or SCS.

So the carriers are out of contention. Th DF-21D has served its purpose.

They can't, first, your satellite need to know what they are looking at, and give a reference point. That mean you need to look at the image yourself and tag the target from the image and allowing the computer to track the target for you.

However, while you are doing that, the satellite will "refresh" and they will prepare the next image. And the next one, and the next one. Meaning you can never do the target acquisition in real time.

Computer power is great today, it is not that advance the computer can distinguish target from different angle. Even if you make a 3D model, the model may not be accurate because there are no way to make an accurate 3d model unless you use a laser and scan the actual carrier in all dimension...

I will post videos, you can check and decide yourself.

I was talking about the starting point, Tracking was not start when the missile come down, it started when the missile goes up.

I am talking about the starting point too. That's the only time the BM is below radar horizon.

So you are basing this on something you don't know and it's not even in reality? Oh well...

If you want to talk about in the future, what make you think in the future, SAM technology will not advance and have a way or ways to deal with hypersonic warhead??

The point is, you don't know what China and US is working on at the moment, maybe they already have an answer for Hypersonic weapon, you don't know that, even I have TS/SCI clearance and I don't know that, you cannot justify what will happen today by looking into the future.

As I said, we don't know what the warhead is.

read this

https://defence.pk/pdf/threads/chin...oups-real-time-position-every-30-mins.479064/

That time given is specified as the minimum amount of time required to ensure real time updates are possible. At the time the article was written, the Chinese were estimated to have up to 4 hours of blindness before a spot is recced by a satellite again. From the link I posted, that time will be improved to 10 min by 2030.

Of course, the above is only for satellites in low earth orbit. But due to advances in technology, they are able to put up more advanced cameras in heavier satellites in GEO. So it's not a problem anymore.

Anyway you said satellites cannot process quickly. Here's real time tracking of cars without any emissions from the cars themselves.

They used this feed from the satellite to create a real time tracking software that detects and tracks vehicle movement quite accurately.

So if they can detect and track cars through all that clutter in real time, then imagine how easy it is to track a CBG in open water.

Check video at 0:21 and 0:47, very relevant to what we are talking about.

The Chinese have satellites capable of doing this in GEO. So they have 24/7 coverage of most of the planet.

 

[jhungary]

So the carriers are out of contention. Th DF-21D has served its purpose.

Why and How?

In war, information is still what you are fighting for, how do you know I have deployed my carrier or not? Or I did not just use the Airfield in Japan and South Korea?

Jjust because I don't need to does not mean I will not use them. It will still give you something to think about and it will force your hand and you will have to deploy these missile just in case, more asset in theatre mean more asset to support, which mean you will stretch thin your support system.

Which, by the way, favour me, not you.

I will post videos, you can check and decide yourself.

okay

Yes, you will see.

Okay

 

[Imran Khan]

for countries like us we can have only this what
BD navy doing it

 

[jhungary]

That time given is specified as the minimum amount of time required to ensure real time updates are possible. At the time the article was written, the Chinese were estimated to have up to 4 hours of blindness before a spot is recced by a satellite again. From the link I posted, that time will be improved to 10 min by 2030.

Of course, the above is only for satellites in low earth orbit. But due to advances in technology, they are able to put up more advanced cameras in heavier satellites in GEO. So it's not a problem anymore.

Anyway you said satellites cannot process quickly. Here's real time tracking of cars without any emissions from the cars themselves.

They used this feed from the satellite to create a real time tracking software that detects and tracks vehicle movement quite accurately.

So if they can detect and track cars through all that clutter in real time, then imagine how easy it is to track a CBG in open water.

Check video at 0:21 and 0:47, very relevant to what we are talking about.

The Chinese have satellites capable of doing this in GEO. So they have 24/7 coverage of most of the planet.

The video is tracking car moving along a surface, in computer science, it detect the state change. (What the computer do is simply take 2 image and compare the pixel and see what "Moved" since the street and the bridge does not move, meaning the thing that move is a car.)

THAT IS NOT WHAT I MEAN.

In this case, can you tell which car is a sedan? You can't, because the there are no resolution and definition available to the computer as to what is a sedan, all the computer see is state change, but they cannot distinguish what has change and what has not. Simply, for the computer, the "car" is simply a "state" which change. All it detach is something is moving. Car move on the street, Truck move on the street, Van move on the street, you cannot tell which is which from the video.

Can the satellite tell me which one of the moving dot is a car? Which one of the moving dot is a van? Which one of the moving dot is a truck? Which one of the moving dot is a bus? Or which one of the moving is a tank? It can't

Now. imagine this, if I want to track a specific car within all the car. It cannot be done as there are no definition of what is a sedan and what is a hatchback.

In this case, how do you know that dot is an aircraft carrier? In open ocean, there exist many ship, how do the computer know that is an aircraft carrier to begin with? When the dot is nothing more than a state. it could have been a cargo ship, it could have been a yacht, it could have been a glitch.

 

[gambit]

Ok so when it comes to DF21D its highly speculative but when it is about SM-3 it is based on some out of the world tech that cannot be failed ... You are biased and therefore cannot be reasoned with ...

No, the SM-3 is based on sound science and engineering. I maybe biased but at least I am reasonable, unlike you.

So what you are suggesting that China is mass producing a missile without testing? I think this assumption is wrong as it is a deployed missile ...

No one is suggesting such a thing.

To start off...You can deploy anything you like, tested or not.

What we are saying is that the DF-21D to date have no known open water test against a moving target that has full countermeasures. Such a test would be the most realistic but unachievable since China does not have access to a US aircraft carrier to conduct such a test. At best, China can only test against half capable targets.

Furthermore, if you have read my post I have never questioned the credibility of SM-3 but what I am saying that even in best of the performance it do not have 100% kill ratio so in case of a real war (assuming USA attacked China) ,,, China will definitely fire multiple warheads so SM-3 has to successfully intercept it all the times but DF21D have to beat defenses just a single time ...

Since you ran away when you cannot meet my challenge, for the sake of others, I will show the forum how the DF-21D is not as scary as the Chinese would like people to believe.

A descending ballistic body is what we call an 'irreversible' body. In an aircraft, as long as fuel remains, I can move up/down/left/right as I chose. But once fuel is exhausted, there is only one way -- down -- and it is irreversible.

What this mean is that interception of the descending ballistic warhead, from a sensor perspective, is quite easy. There is the Doppler component and that is all we need, even though we use more. What make an interception difficult is if the interception is physical, as in 'hitting a bullet with another bullet'. If the interceptor miss, it has no chance to reacquire the target.

The SM-3 have had successful physical interceptions of targets in both exo and atmospheric targets.

 

[randomradio]

The video is tracking car moving along a surface, in computer science, it detect the state change. (What the computer do is simply take 2 image and compare the pixel and see what "Moved" since the street and the bridge does not move, meaning the thing that move is a car.)

THAT IS NOT WHAT I MEAN.

In this case, can you tell which car is a sedan? You can't, because the there are no resolution and definition available to the computer as to what is a sedan, all the computer see is state change, but they cannot distinguish what has change and what has not. Simply, for the computer, the "car" is simply a "state" which change. All it detach is something is moving. Car move on the street, Truck move on the street, Van move on the street, you cannot tell which is which from the video.

Can the satellite tell me which one of the moving dot is a car? Which one of the moving dot is a van? Which one of the moving dot is a truck? Which one of the moving dot is a bus? Or which one of the moving is a tank? It can't

Now. imagine this, if I want to track a specific car within all the car. It cannot be done as there are no definition of what is a sedan and what is a hatchback.

In this case, how do you know that dot is an aircraft carrier? In open ocean, there exist many ship, how do the computer know that is an aircraft carrier to begin with? When the dot is nothing more than a state. it could have been a cargo ship, it could have been a yacht, it could have been a glitch.

Doing the above requires a lot of work. For example, you will need 2D images of the object from as many angles/orientations as possible.

This is a bit about how Google search for images works.
https://www.quora.com/How-does-Google-image-search-engine-work

• We can recognize any famous landmarks (and we have sophisticated techniques for recognizing them from any angle)
• We can recognize objects - vehicles, buildings, animal species

So take the picture of carriers, destroyers etc from multiple angles, the satellite will correlate the image it took with a database of images. It basically does a Google search on those images. Then it tells a bunch of people what it found, and the humans take over.

Read this:
It's about automated feature recognition.
http://cs229.stanford.edu/proj2014/...ndmark Recognition Using Machine Learning.pdf

It will clear your doubts about that "track a specific car within all the car" problem as well.

http://www.kurzweilai.net/apples-first-ai-paper-focuses-on-creating-superrealistic-image-recognition

So, basically, a satellite (and assorted ground control equipment as well) can detect, identify, classify, prioritize the threat and then inform the operators to take action.

In fact, in a few years we will start seeing satellites with large telescopes, probably 20m and greater, which will be able to track people with great accuracy.
https://phys.org/news/2014-04-telescope-tech-membrane-optics-phase.html

Let's not forget that even SAR/ISAR satellites are used to complement the optical satellites.

 

[Taj_91]

@jhungary
I think it is quite easy to detect 3d objects from a 2d image. Nimitz class carrier is 332m approx, surely I can get a good enough 3d model of it from net. I have my satellite's attitude angles with me, using that I can do a 3D to 2D projection of the carrier's top from my that particular angle and superimpose on the images I receive from the satellite. Size of 332m, it can be easily detected by mil satellites, for a good enough match of say 85% you can call a human. If it matches, the satellite has only to track in the vicinity of the previous image, knowing the time stamp and max speed of carrier it would be done.
What's wrong with this?
This won't take time once a match is made. The only lag will be from satellites transmission and whether there are other satellites covering that particular area.
In the car's example, if you can get a particular signature, say licence plate, you can track it? Just need good processors.

 

[jhungary]

Doing the above requires a lot of work. For example, you will need 2D images of the object from as many angles/orientations as possible.

This is a bit about how Google search for images works.
https://www.quora.com/How-does-Google-image-search-engine-work

• We can recognize any famous landmarks (and we have sophisticated techniques for recognizing them from any angle)
• We can recognize objects - vehicles, buildings, animal species

So take the picture of carriers, destroyers etc from multiple angles, the satellite will correlate the image it took with a database of images. It basically does a Google search on those images. Then it tells a bunch of people what it found, and the humans take over.

Read this:
It's about automated feature recognition.
http://cs229.stanford.edu/proj2014/Andrew Crudge, Will Thomas, Kaiyuan Zhu, Landmark Recognition Using Machine Learning.pdf

It will clear your doubts about that "track a specific car within all the car" problem as well.

http://www.kurzweilai.net/apples-first-ai-paper-focuses-on-creating-superrealistic-image-recognition

So, basically, a satellite (and assorted ground control equipment as well) can detect, identify, classify, prioritize the threat and then inform the operators to take action.

In fact, in a few years we will start seeing satellites with large telescopes, probably 20m and greater, which will be able to track people with great accuracy.
https://phys.org/news/2014-04-telescope-tech-membrane-optics-phase.html

Let's not forget that even SAR/ISAR satellites are used to complement the optical satellites.

It's not how google image reverse search work at all.....

For image search to work, the input have to be able to provide at least two reference point for the computer to do the search, if you had REALLY read the article by Stanford, you will understand the landmark is compare by the data refer to correspond to the landmark itself, because landmark have a distinct measurement when they are compare to the surrounding. Because;

1.) Landmark don't move, the reference point can only be detected by several factors.
2.) Landmark is unique, which mean at least one set data is unique.

What it does was this

They draw a picture and break down the image and compare pixel by pixel, and how well the target lay across the background of the whole picture, and using this anchor point, you can deduced the pixel belong to the same subset of the next pixel, this then created a "State" By analyse the state (ons and offs) and compare them to actual data of the Landmark (Height, Width and so on) You will have a group of landmark in a matrix. What you need then is to scale the actual matrix into the same scale of the incoming photo, and compare, if you have a match, then you found your landmark.

However, when you are talking about a non-unique ship that's moving in the middle of an ocean with no reference point, that's another ballgame.

How do the computer know the "States" of the ship when you have no reference point, no matrix, not background you can compare??

Just because you said a satellite (and assorted ground control equipment as well) can detect, identify, classify, prioritize the threat and then inform the operators to take action Does not make it so.

 

[Taj_91]

It's not how google image reverse search work at all.....

For image search to work, the input have to be able to provide at least two reference point for the computer to do the search, if you had REALLY read the article by Stanford, you will understand the landmark is compare by the data refer to correspond to the landmark itself, because landmark have a distinct measurement when they are compare to the surrounding. Because;

1.) Landmark don't move, the reference point can only be detected by several factors.
2.) Landmark is unique, which mean at least one set data is unique.

What it does was this

They draw a picture and break down the image and compare pixel by pixel, and how well the target lay across the background of the whole picture, and using this anchor point, you can deduced the pixel belong to the same subset of the next pixel, this then created a "State" By analyse the state (ons and offs) and compare them to actual data of the Landmark (Height, Width and so on) You will have a group of landmark in a matrix. What you need then is to scale the actual matrix into the same scale of the incoming photo, and compare, if you have a match, then you found your landmark.

However, when you are talking about a non-unique ship that's moving in the middle of an ocean with no reference point, that's another ballgame.

How do the computer know the "States" of the ship when you have no reference point, no matrix, not background you can compare??

Just because you said a satellite (and assorted ground control equipment as well) can detect, identify, classify, prioritize the threat and then inform the operators to take action Does not make it so.

Do you know how horizon detection works? The earlier ones used rgb difference between that of sky and ground to detect the horizons. You can also use texture to differentiate between the sky and ground.
When I have an image from the satellite, I can do a simple rgb analysis to point the odd ones out. In the image of an ocean, it will be a vast expanse of blue. Any ship will stand out on rough rgb analysis. Using this odd shape out and comparing with 2D projection of carrier knowing the attitude angles of satellites, I can compare the two and get a match. No requirements of landmarks.
Every problem has got its own solution, here you don't need landmarks.