DF 21D VS bRAHMOS 2 HYPERSONIC aSCM A LAYMAN COMPARISION

[gambit]

I see the accuracy of DF-21 is estimated at 50 meters or less....

don't be put off by it... 50m would be for the near maximum ranges and if a ASBM where to hit even <50m from a target ship or even carrier, it would knock it out quite easily.

as ever..... thanks for the info Dr saab!

In a missile versus ship scenario, if the missile failed by just one meter, the ship won...

The preferable ones are: 'High accuracy, High precision' and 'High accuracy, Low precision'.

Obviously, we all want 'High accuracy, High precision'. But if due to technical reasons we cannot, then 'High accuracy, Low precision' will give us better odds of hitting a MOVING target like a ship because the ship will be within the CEP field as illustrated. Of course, with this low precision weapon, more must be launched to have a reasonable coverage of that field.

Here is another way of looking at CEP...

The above is an illustration of 'rapid runway repair' after a saturation bombardment by an enemy. The highlighted strip is the minimum amount of continuous runway required for air operation. That strip could be from being repaired or just from sheer luck that such an area escaped being damaged. It is not that difficult to notice that this strip is very similar to an aircraft carrier and one can imagine the possibility that the ship escaped a saturation attack by 'low precision' weapons.

It is not that easy to successfully perform a 'runway denial' mission and we are looking at a FIXED target: A land airbase. So it is amusing to see the Chinese members here going ga-ga over the DF-21D trying to go after a MOVING target amidst literally millions of square km of ocean surface.

 

[DrSomnath999]

In a missile versus ship scenario, if the missile failed by just one meter, the ship won...

The preferable ones are: 'High accuracy, High precision' and 'High accuracy, Low precision'.

Obviously, we all want 'High accuracy, High precision'. But if due to technical reasons we cannot, then 'High accuracy, Low precision' will give us better odds of hitting a MOVING target like a ship because the ship will be within the CEP field as illustrated. Of course, with this low precision weapon, more must be launched to have a reasonable coverage of that field.

Here is another way of looking at CEP...

The above is an illustration of 'rapid runway repair' after a saturation bombardment by an enemy. The highlighted strip is the minimum amount of continuous runway required for air operation. That strip could be from being repaired or just from sheer luck that such an area escaped being damaged. It is not that difficult to notice that this strip is very similar to an aircraft carrier and one can imagine the possibility that the ship escaped a saturation attack by 'low precision' weapons.

It is not that easy to successfully perform a 'runway denial' mission and we are looking at a FIXED target: A land airbase. So it is amusing to see the Chinese members here going ga-ga over the DF-21D trying to go after a MOVING target amidst literally millions of square km of ocean surface.

thanks for posting ur views sir .
Well sir i agree to ur 1st statement but do u think CEP value of less than < 50 meter backed by terminal guidance would make a
succesful hit by DF 21d as comparing the dimension of aircraft carrier it's cep value is well within it's diamter.

Yes 1 thing i must agree it is not going to be easy to target a mobile target no matter how huge the target may be at such a long distance

 

[The enlightened]

can df-21 not be intercepted with THAAD

 

[5ever]

The difference is the use of a DF21 missile on an US carrier will equal to a kerbstomp of majestic proportions for China.

 

[Jungibaaz]

In a missile versus ship scenario, if the missile failed by just one meter, the ship won...

The preferable ones are: 'High accuracy, High precision' and 'High accuracy, Low precision'.

Obviously, we all want 'High accuracy, High precision'. But if due to technical reasons we cannot, then 'High accuracy, Low precision' will give us better odds of hitting a MOVING target like a ship because the ship will be within the CEP field as illustrated. Of course, with this low precision weapon, more must be launched to have a reasonable coverage of that field.

Here is another way of looking at CEP...

The above is an illustration of 'rapid runway repair' after a saturation bombardment by an enemy. The highlighted strip is the minimum amount of continuous runway required for air operation. That strip could be from being repaired or just from sheer luck that such an area escaped being damaged. It is not that difficult to notice that this strip is very similar to an aircraft carrier and one can imagine the possibility that the ship escaped a saturation attack by 'low precision' weapons.

It is not that easy to successfully perform a 'runway denial' mission and we are looking at a FIXED target: A land airbase. So it is amusing to see the Chinese members here going ga-ga over the DF-21D trying to go after a MOVING target amidst literally millions of square km of ocean surface.

quite simply, the size of the aircraft carriers would be bigger then the degree of accuracy, that illustration you've shown, what do those compare to a 600kg warhead?

Not to mention... what can aircraft carriers do that land airstrips can't? sink...

DF-21D uses active guidance systems, If it can hit an aircraft carrier with dimensions of large aircraft carriers, given that it is armed with a good size warhead... the aircraft carrier would be history.

 

[DrSomnath999]

can df-21 not be intercepted with THAAD

possible counter weapon against DF 21d

(1)AEGIS SM3 interceptor
(2)Air borne laser missile defence to shoot it down in boost phase
(3)Ship based LAser missile defence system.
(4)To destroy it's launcher through precision attack like emp armed cruise missile,Precision giuded bombs & mk105 sensor fuze cluster weapons or kamakaze drones .

 

[DrSomnath999]

quite simply, the size of the aircraft carriers would be bigger then the degree of accuracy, that illustration you've shown, what do those compare to a 600kg warhead?

Not to mention... what can aircraft carriers land airstrips can't? sink...

DF-21D uses active guidance systems, If it can hit an aircraft carrier with dimensions of large aircraft carriers, given that it is armed with a good size warhead... the aircraft carrier would be history.

well no question of nuclear weapons comes to here as use of nukes would be suicadal for china as it would provoke a nuclear war
Well chinese must have good accurate terminal guidance buddy which is going to be against a mobile target moving at a speed of 30 knots that aint easy at such a long range

 

[Jungibaaz]

well no question of nuclear weapons comes to here as use of nukes would be suicadal for china as it would provoke a nuclear war
Well chinese must have good accurate terminal guidance buddy which is going to be against a mobile target moving at a speed of 30 knots that aint easy at such a long range

It's not easy... I don't know if they can do it, but I'm going with what info they've provided us with.

 

[DrSomnath999]

It's not easy... I don't know if they can do it, but I'm going with what info they've provided us with.

well what information they have provided us kindly tell ? & did they conduct any live test against a moving target to confirm it .If yes then post the link

 

[gambit]

Well sir i agree to ur 1st statement but do u think CEP value of less than < 50 meter backed by terminal guidance would make a succesful hit by DF 21d as comparing the dimension of aircraft carrier it's cep value is well within it's diamter.

No, and am certain the Chinese boys here will howl with indignation over the answer.

Circular Error Probability

The CEP is a term normally associated with ballistic missile systems but can be applied to any ground to ground or air to ground missile system. The Circular Error Probability is a circular area around the target within which a warhead has 50% chance of landing.

The problem here is the persistent misuse of the CEP figure when said figure is derived from an ideal mathematical environment. The highlighted is significant.

What this ideal mathematical environment mean is that from a center, not THE center of a target, but simply 'center', the CEP figure is saying that given x amount of munitions thrown at this theoretical center, 50% of x will be within y distance, say meters for now, of that center. Inside this 50% there will be an unknown amount that can (not assured) hit the center. Of the other 50% we will have a distribution, or spread, of munitions that will be 2-3 times y-meters further from center.

Here is the problem FROM A SENSORY PERSPECTIVE...

Currently deployed sensors, radar or infrared (IR), have a difficult time calculating THE center of a physical target with IR the worst. The analogy here, especially for IR, is if you are looking at the light of the flashlight. Can you tell where that center is? No, you cannot. You can tell where the light begins to 'thin' out, in other words, you can tell the peripheral edges of the spread. But if you look straight at the light itself, there is an exact center but within a certain area spread your eyes are overwhelmed by the light's intensity that you simply cannot determine that exact center. Try it. Take a good Mag-lite, turn it on, and look straight into the lens.

Does a physical target have an exact physical center? You bet. But what sensors, radar and IR, do is to calculate the PERCEIVED target based upon the decreasing intensity created by the target that ended with its peripheral edges, in other words, the sensor will take the area of the highest intensity, scan outward towards the lowest intensity, scan back in again, then determine that this is the target, not THE physical center of the target.

This is why from radar perspective, the target is PERCEIVED to be 10-meters/squared, but there is no mention of the exact physical center of that figure. If the target is moving, then it will vary between 10m2 to less, so how is the sensor package be able to determine the exact physical center of the target? Not at all with the current technology. That is why we have video imagery guidance of certain munitions. The human operator look at the target, determine that it is a 'tank', then guide the crosshair to what he know is the physical center of the tank. The munition then tries to maneuver itself towards the target. It is the human who decide WHERE is the physical center of the target.

This lead us back to the CEP figure. Assume the munition has a CEP figure of 10 meters. But 10m from where? From the bow? Or stern? For an aircraft carrier, the distance between bow and stern is about 330m. If a DF-21D warhead struck the stern, that is a hit but is it sufficiently debilitating? Absolutely not. If it hit on the exact physical center of the deck, that is another story, but one that would a great deal of luck involved.

This is why the CEP figure against a physical target should be taken with a grain of salt when it comes to efficacy...

Efficacy - Wikipedia, the free encyclopedia

Efficacy is the capacity to produce an effect.

The effect is to halt air operations on an aircraft carrier. But will it halt if only an elevator is hit? No. We can say that the warhead is within that 50% circle but did it produced the desired effect? No.

Say that the target has a 10m2 radar cross section (RCS). Inside the electronics, this would be represented by a voltage spike, or difference, depends on who is speaking. All voltage spikes have a rise and a fall. The sharper or more rapid the voltage rise, the shorter the range between the beginning and the end. The more gradual that rise, the greater the range or spread. Over time, of course. The more sophisticated radar package can attempt to calculate the physical center of a target based upon this range or spread of the voltage spike and home in on this perceived center.

We know this...

What we can do is to present to the sensor a greater voltage spike with a greater range between start and end via countermeasures like chaff, which can create a radar view and RCS of thousands of square meters. The ship can be anywhere under this blanket. The behavior of chaff launched by a ship is different than when discharged by an aircraft. When an aircraft fired off chaff, there is an immediate difference in velocity and travel direction between the chaff cloud and the aircraft. A missile can pick up this difference and continue to track the aircraft. Not so when a ship launch chaff. The chaff cloud can continue to blanket the ship for several MINUTES instead of a few seconds. The ship's movement will produce no practical usable Doppler signals because it is moving laterally across the radar's view. Doppler is best when the target is moving towards or away from the seeking radar. So even if the DF-21D warhead managed to acquire the ship before chaff is launched, once its radar view is covered by chaff, it can only continue to home in on the ship's last known position in memory, not where the ship has moved, and if the warhead missed the ship by just one meter, the ship won.

This is why the Chinese boys here do not like to discuss the DF-21D's weaknesses from technical and practical perspectives. They have no relevant experience and they know it. From a sensor specialist standpoint, the DF-21D has plenty of vulnerable areas for US to exploit, down to the terminal stage of the attack. Of course, we do not like to shave it so close. No one does. But that does not mean a US aircraft carrier is completely helpless from the start to the end of a fight.

 

[DrSomnath999]

No, and am certain the Chinese boys here will howl with indignation over the answer.

who the **** cares for them let them howl whatever they want

Circular Error Probability

The problem here is the persistent misuse of the CEP figure when said figure is derived from an ideal mathematical environment. The highlighted is significant.

What this ideal mathematical environment mean is that from a center, not THE center of a target, but simply 'center', the CEP figure is saying that given x amount of munitions thrown at this theoretical center, 50% of x will be within y distance, say meters for now, of that center. Inside this 50% there will be an unknown amount that can (not assured) hit the center. Of the other 50% we will have a distribution, or spread, of munitions that will be 2-3 times y-meters further from center.

Here is the problem FROM A SENSORY PERSPECTIVE...

Currently deployed sensors, radar or infrared (IR), have a difficult time calculating THE center of a physical target with IR the worst. The analogy here, especially for IR, is if you are looking at the light of the flashlight. Can you tell where that center is? No, you cannot. You can tell where the light begins to 'thin' out, in other words, you can tell the peripheral edges of the spread. But if you look straight at the light itself, there is an exact center but within a certain area spread your eyes are overwhelmed by the light's intensity that you simply cannot determine that exact center. Try it. Take a good Mag-lite, turn it on, and look straight into the lens.

Does a physical target have an exact physical center? You bet. But what sensors, radar and IR, do is to calculate the PERCEIVED target based upon the decreasing intensity created by the target that ended with its peripheral edges, in other words, the sensor will take the area of the highest intensity, scan outward towards the lowest intensity, scan back in again, then determine that this is the target, not THE physical center of the target.

This is why from radar perspective, the target is PERCEIVED to be 10-meters/squared, but there is no mention of the exact physical center of that figure. If the target is moving, then it will vary between 10m2 to less, so how is the sensor package be able to determine the exact physical center of the target? Not at all with the current technology. That is why we have video imagery guidance of certain munitions. The human operator look at the target, determine that it is a 'tank', then guide the crosshair to what he know is the physical center of the tank. The munition then tries to maneuver itself towards the target. It is the human who decide WHERE is the physical center of the target.

This lead us back to the CEP figure. Assume the munition has a CEP figure of 10 meters. But 10m from where? From the bow? Or stern? For an aircraft carrier, the distance between bow and stern is about 330m. If a DF-21D warhead struck the stern, that is a hit but is it sufficiently debilitating? Absolutely not. If it hit on the exact physical center of the deck, that is another story, but one that would a great deal of luck involved.

This is why the CEP figure against a physical target should be taken with a grain of salt when it comes to efficacy...

well sir do u think IR sensor would work at such high temperature usually when the reentry vehicle enters the atmosphere .I doubt,whats ur opinion?

Efficacy - Wikipedia, the free encyclopedia

The effect is to halt air operations on an aircraft carrier. But will it halt if only an elevator is hit? No. We can say that the warhead is within that 50% circle but did it produced the desired effect? No.

Say that the target has a 10m2 radar cross section (RCS). Inside the electronics, this would be represented by a voltage spike, or difference, depends on who is speaking. All voltage spikes have a rise and a fall. The sharper or more rapid the voltage rise, the shorter the range between the beginning and the end. The more gradual that rise, the greater the range or spread. Over time, of course. The more sophisticated radar package can attempt to calculate the physical center of a target based upon this range or spread of the voltage spike and home in on this perceived center.

We know this...

What we can do is to present to the sensor a greater voltage spike with a greater range between start and end via countermeasures like chaff, which can create a radar view and RCS of thousands of square meters. The ship can be anywhere under this blanket. The behavior of chaff launched by a ship is different than when discharged by an aircraft. When an aircraft fired off chaff, there is an immediate difference in velocity and travel direction between the chaff cloud and the aircraft. A missile can pick up this difference and continue to track the aircraft. Not so when a ship launch chaff. The chaff cloud can continue to blanket the ship for several MINUTES instead of a few seconds. The ship's movement will produce no practical usable Doppler signals because it is moving laterally across the radar's view. Doppler is best when the target is moving towards or away from the seeking radar. So even if the DF-21D warhead managed to acquire the ship before chaff is launched, once its radar view is covered by chaff, it can only continue to home in on the ship's last known position in memory, not where the ship has moved, and if the warhead missed the ship by just one meter, the ship won.

This is why the Chinese boys here do not like to discuss the DF-21D's weaknesses from technical and practical perspectives. They have no relevant experience and they know it. From a sensor specialist standpoint, the DF-21D has plenty of vulnerable areas for US to exploit, down to the terminal stage of the attack. Of course, we do not like to shave it so close. No one does. But that does not mean a US aircraft carrier is completely helpless from the start to the end of a fight.

well sir u post a verry ...... verry technical answer ,i hope chinese defence scientist take note of this .

---------- Post added at 11:07 PM ---------- Previous post was at 11:07 PM ----------

No, and am certain the Chinese boys here will howl with indignation over the answer.

who the **** cares for them let them howl whatever they want

Circular Error Probability

The problem here is the persistent misuse of the CEP figure when said figure is derived from an ideal mathematical environment. The highlighted is significant.

What this ideal mathematical environment mean is that from a center, not THE center of a target, but simply 'center', the CEP figure is saying that given x amount of munitions thrown at this theoretical center, 50% of x will be within y distance, say meters for now, of that center. Inside this 50% there will be an unknown amount that can (not assured) hit the center. Of the other 50% we will have a distribution, or spread, of munitions that will be 2-3 times y-meters further from center.

Here is the problem FROM A SENSORY PERSPECTIVE...

Currently deployed sensors, radar or infrared (IR), have a difficult time calculating THE center of a physical target with IR the worst. The analogy here, especially for IR, is if you are looking at the light of the flashlight. Can you tell where that center is? No, you cannot. You can tell where the light begins to 'thin' out, in other words, you can tell the peripheral edges of the spread. But if you look straight at the light itself, there is an exact center but within a certain area spread your eyes are overwhelmed by the light's intensity that you simply cannot determine that exact center. Try it. Take a good Mag-lite, turn it on, and look straight into the lens.

Does a physical target have an exact physical center? You bet. But what sensors, radar and IR, do is to calculate the PERCEIVED target based upon the decreasing intensity created by the target that ended with its peripheral edges, in other words, the sensor will take the area of the highest intensity, scan outward towards the lowest intensity, scan back in again, then determine that this is the target, not THE physical center of the target.

This is why from radar perspective, the target is PERCEIVED to be 10-meters/squared, but there is no mention of the exact physical center of that figure. If the target is moving, then it will vary between 10m2 to less, so how is the sensor package be able to determine the exact physical center of the target? Not at all with the current technology. That is why we have video imagery guidance of certain munitions. The human operator look at the target, determine that it is a 'tank', then guide the crosshair to what he know is the physical center of the tank. The munition then tries to maneuver itself towards the target. It is the human who decide WHERE is the physical center of the target.

This lead us back to the CEP figure. Assume the munition has a CEP figure of 10 meters. But 10m from where? From the bow? Or stern? For an aircraft carrier, the distance between bow and stern is about 330m. If a DF-21D warhead struck the stern, that is a hit but is it sufficiently debilitating? Absolutely not. If it hit on the exact physical center of the deck, that is another story, but one that would a great deal of luck involved.

This is why the CEP figure against a physical target should be taken with a grain of salt when it comes to efficacy...

well sir do u think IR sensor would work at such high temperature usually when the reentry vehicle enters the atmosphere .I doubt,whats ur opinion?

Efficacy - Wikipedia, the free encyclopedia

The effect is to halt air operations on an aircraft carrier. But will it halt if only an elevator is hit? No. We can say that the warhead is within that 50% circle but did it produced the desired effect? No.

Say that the target has a 10m2 radar cross section (RCS). Inside the electronics, this would be represented by a voltage spike, or difference, depends on who is speaking. All voltage spikes have a rise and a fall. The sharper or more rapid the voltage rise, the shorter the range between the beginning and the end. The more gradual that rise, the greater the range or spread. Over time, of course. The more sophisticated radar package can attempt to calculate the physical center of a target based upon this range or spread of the voltage spike and home in on this perceived center.

We know this...

What we can do is to present to the sensor a greater voltage spike with a greater range between start and end via countermeasures like chaff, which can create a radar view and RCS of thousands of square meters. The ship can be anywhere under this blanket. The behavior of chaff launched by a ship is different than when discharged by an aircraft. When an aircraft fired off chaff, there is an immediate difference in velocity and travel direction between the chaff cloud and the aircraft. A missile can pick up this difference and continue to track the aircraft. Not so when a ship launch chaff. The chaff cloud can continue to blanket the ship for several MINUTES instead of a few seconds. The ship's movement will produce no practical usable Doppler signals because it is moving laterally across the radar's view. Doppler is best when the target is moving towards or away from the seeking radar. So even if the DF-21D warhead managed to acquire the ship before chaff is launched, once its radar view is covered by chaff, it can only continue to home in on the ship's last known position in memory, not where the ship has moved, and if the warhead missed the ship by just one meter, the ship won.

This is why the Chinese boys here do not like to discuss the DF-21D's weaknesses from technical and practical perspectives. They have no relevant experience and they know it. From a sensor specialist standpoint, the DF-21D has plenty of vulnerable areas for US to exploit, down to the terminal stage of the attack. Of course, we do not like to shave it so close. No one does. But that does not mean a US aircraft carrier is completely helpless from the start to the end of a fight.

well sir u post a verry ...... verry technical answer ,i hope chinese defence scientist take note of this .

 

[gambit]

well what information they have provided us kindly tell ? & did they conduct any live test against a moving target to confirm it .If yes then post the link

That is another serious problem for the Chinese claim. Look at the map, specifically China's access to the sea. One side. The US has the Pacific and the Atlantic.

It is a courtesy, not a requirement, to inform other countries when conducting rocket test launches.

Ballistic Missile Launch Notification Agreement

The Agreement on Notifications of ICBM and SLBM Launches, signed during the 1988 Moscow Summit, reflects the continuing interest of the United States and the Soviet Union in reducing the risk of nuclear war as a result of misinterpretation, miscalculation, or accident.

No one is under any obligations to inform anyone else, even close neighbors, of impending test launches. But it is a courtesy in the interest of preserving the peace.

Anyway...What this mean is that regardless of any agreement between anyone, the fact that China's test launches of any missile weapon system is limited mean that China is under constant surveillance by US, Japan, and South Korea. If there has been any successful unrestrained target hits by DF-21D tests, we would know about it.

 

[gambit]

well sir do u think IR sensor would work at such high temperature usually when the reentry vehicle enters the atmosphere .I doubt,whats ur opinion?

No, it would not. Infrared sensor require distinction or contrast between IR sources. If the body carrying the sensor is generating IR radiation by itself, the proximity between this source and the sensor would overwhelm the sensor.

 

[DrSomnath999]

That is another serious problem for the Chinese claim. Look at the map, specifically China's access to the sea. One side. The US has the Pacific and the Atlantic.

It is a courtesy, not a requirement, to inform other countries when conducting rocket test launches.

Ballistic Missile Launch Notification Agreement

No one is under any obligations to inform anyone else, even close neighbors, of impending test launches. But it is a courtesy in the interest of preserving the peace.

Anyway...What this mean is that regardless of any agreement between anyone, the fact that China's test launches of any missile weapon system is limited mean that China is under constant surveillance by US, Japan, and South Korea. If there has been any successful unrestrained target hits by DF-21D tests, we would know about it.

well that's what i am saying without live test how can u confirm it works .Well i assume it is a sort of pschological war chinese are doing with the US
without any test it is impossible to assume chinese have this capabilty

---------- Post added at 11:19 PM ---------- Previous post was at 11:16 PM ----------

No, it would not. Infrared sensor require distinction or contrast between IR sources. If the body carrying the sensor is generating IR radiation by itself, the proximity between this source and the sensor would overwhelm the sensor.

exactly the same theory stated by another respected member of another forum to me that it wont work .So what guidance would really be employed by chinese in it's terminal guidance i doubt

 

[gambit]

well that's what i am saying without live test how can u confirm it works .Well i assume it is a sort of pschological war chinese are doing with the US
without any test it is impossible to assume chinese have this capabilty

What you can do is perform discrete tests on individual components. The greater the reliability of these tests, the higher the odds of when all components are finally integrated into the intended weapon, it will work as designed. With this testing regime, there would be little chance of US or anyone to detect and monitor the progress of a weapon system.

But there is a concern with ANY electro-mechanical devices...

Byzantine fault tolerance - Wikipedia, the free encyclopedia

The object of Byzantine fault tolerance is to be able to defend against Byzantine failures, in which components of a system fail in arbitrary ways (i.e., not just by stopping or crashing but by processing requests incorrectly, corrupting their local state, and/or producing incorrect or inconsistent outputs.). Correctly functioning components of a Byzantine fault tolerant system will be able to correctly provide the system's service assuming there are not too many Byzantine faulty components.

A Byzantine error or even failure is a potential and under a highly restrictive and compartmentalized testing regime as speculated above, the odds of this greatly increases. Components intended to use each other's inputs must be tested together to see if all inputs are properly detected and used. If there are any design flaws, not just material defects or manufacturing mistakes, said Byzantine errors will reveal themselves at these stages. Highly compartmentalized and non-incorporated testings will hide them, often will result in a catastrophic failure at the final stage.