DF-21 - China Nuclear Forces
Can hit a maneuvering target whose length is equal to or less than the CEP figure itself.Configuration Two Stage
Length [meters] 10.7
Diameter [meters] 1.4
Mass [kilograms] 14,700
First Flight May 1985
Range (km) 1,800
Re-entry Vehicle Mass (kg) 600
Warhead Yield 200-300 KT
CEP (meters) 300-400
Launch Preparation Time 10-15 minutes
every chinese ballistic missiles can reach that number
there is the detail about the CEP,ignore the chinese words,pick the number you can read:
Last edited by aimarraul; 10-26-2009 at 09:06 PM.
Circular Error Probability
So if we launch a missile whose warhead has a CEP of 300-400 meters, it mean the warhead could land inside that circle but at the edge of that circle. Or it could get lucky and hit center. Or anywhere in between. Why is that a good weapon against a maneuvering target?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. Obviously this concept is of little use unless a weapon is high yield or is carrying submuntions which cover a large area.
It was leaked a while ago (again, no one can vouch for its authenticity) that it can tigthen up the CEP considerably to meet the necessary tactical requirement.
In contrast, India's strategic missiles required tight CEPs in order to have proper deterrance due to comparatively low yield. Again, it all goes back to the mission-oriented "trade-offs" that you repeatedly emphasized.
Your tireless effort in "educating" us is greatly appreciated. But I honestly thought you would be aware of the above.
This has NOTHING to do with the mechanics of what we are talking about. China want to keep the true figure secret? Fine. But assuming that 300-400 meters CEP is reasonably credible, humor the readership and explain how can this weapon be effective against a maneuvering target.
That's exactly what I read about CEPs for strategic vs tactical purposes - I don't have time to dig it up but its' eminently googleble, and I know you know it.
If you think I am out to lunch then pls be "kind and patient" - and explain with one of your diagrams (I like them btw) where my proper lunch ought to be.
Otherwise, we are just wasting bandwidth here.
Till next time, or the next education session.
This topic has been thoroughly defeated, people are collecting pieces and rags now .
Plagiarised idea outsourced from US was never meant to help Chinese enthusiast's cause. China's real capabilities are still hidden but one can bet on contemporary feasible technology available.
People should learn before posting such articles that these claims can be a trap and may fire back. Furthermore one should pour more relevant information to help their own thread rather bullying online.
I still believe that this topic can be rejuvenate again for sake of constructive discussion. But the way people here are making superfluous gestures is causing it to breath ineffectually like many other threads.
Awesome Aegis Ascendant
October 4, 2009:
The U.S. government, encouraged by the high success rate (83 percent) of U.S. Navy Aegis equipped ships using SM-3 missiles to shoot down ballistic missiles, has decided to expand the number of SM-3 equipped ships. Just this year, the navy completed equipping 18 ships with the Aegis anti-missile system, and that number may soon more than triple.
This is part of a larger trend. Last year, the navy cancelled its expensive new DDG-1000 class of destroyers, partly because these ships were built to support amphibious and coastal operations, and did not have a radar that could easily be converted to use SM-3 anti-missile missiles. The DDG-1000 also cost 2-3 times more than Aegis destroyers. With missile defense seen as a higher priority than providing new amphibious and coastal combat capability, the DDG-1000 was killed, and the money saved could be used to build more Aegis destroyers, and convert more current destroyers and cruisers to use SM-3.
With that in mind, the navy is already converting three more Aegis ships to fire anti-missile missiles. This costs about $12 million a ship, mainly for new software and a few new hardware items. This is seen as a safe investment. To knock down ballistic missile, Aegis uses two similar models of the U.S. Navy Standard anti-aircraft missile, in addition to a modified version of the Aegis radar system, tweaked to also track incoming ballistic missiles.
Now the government wants to use Aegis more aggressively to block Iranian or North Korean ballistic missiles, and is proposing that nearly all (over 60) ships equipped with Aegis radar systems, be converted to fire SM-3 anti-missile missiles. This would mean buying over a thousand SM-3 missiles. These currently cost about $10 million each, and the next upgrade (which will deliver more accuracy and reliability) will raise that to $15 million each. While the expanded Aegis program will cost about $20 billion, it's seen as the cheapest way to provide reliable anti-missile defense against Iran and North Korea.
The RIM-161A, also known as the Standard Missile 3 (or SM-3), has a range of over 500 kilometers and max altitude of over 160 kilometers. The Standard 3 is based on the anti-missile version of the Standard 2 (SM-2 Block IV). This SM-2 missile turned out to be effective against ballistic missile warheads that are closer to their target. One test saw a SM-2 Block IV missile destroy a warhead that was only 19 kilometers up. An SM-3 missile can destroy a warhead that is more than 200 kilometers up. But the SM-3 is only good for anti-missile work, while the SM-2 Block IV can be used against both ballistic missiles and aircraft. The SM-2 Block IV also costs less than half what an SM-3 costs.
The SM-3 has four stages. The first two boost the interceptor out of the atmosphere. The third stage fires twice to boost the interceptor farther beyond the earth's atmosphere. Prior to each motor firing it takes a GPS reading to correct course for approaching the target. The fourth stage is the 20 pound LEAP kill vehicle, which uses infrared sensors to close on the target and ram it. The Aegis system was designed to operate aboard warships (cruisers and destroyers that have been equipped with the special software that enables the AEGIS radar system to detect and track incoming ballistic missiles). However, there is also a land based version that Israel is interested in buying
We (non-techies/non-insiders) are fully cognizant of the argument that the quoted CEP of 300-400 meters would make the claim of a tactical ballistic missile hitting three football fields back-to-back moving along at a good clip a little incredulous.
I am simply questioning whether PRC planners would take a "strategic" short/medium range missile and use it unmodified to pretend that it could be a threat against vaunted American fortresses at sea.
Maybe the PLA Honchos are just the irresponsible, mouth-flapping, chest-thumping types, you know, although it was strange no thumping was heard after the ASAT test, until Uncle found it expedient to make hay of the fact that hundreds/thousands pieces of debris were floating in outer space and "endangered other peaceable satellites" ...
Maybe the test in the Yellow Sea never took place. Maybe the so-called "Second Artillery Corp" was non-existent, just like Sadam's "WMD". Maybe the entire PRC space program was a hoax. Maybe Neal Armstrong just walked around Arizona and called it the "moon" ...
Who knows, it's all hearsay, isn't it?
Last edited by oceanx; 10-26-2009 at 11:02 PM. Reason: numerical error
Circular Error Probable (CEP)
A measure of missile accuracy. A missile's CEP is the radius of a circle around the target in which 50% of the warheads aimed at that target will land.
CEP 400m means there will be 50% probability that the warhead will land within the circle of 400m radius. This circle will have an area of 400*400*pi=502,654m^2
By ignoring system error (as system error is a constant deviation and can be adjusted in many cases), a carrier will be in the center of the circle.
Suppose the carrier is Nimitz class, to simplify, it has an area of 300*100=30,000m^2.
To underestimate the hit probability, suppose within the circle, the missiles will be evenly distributed in probability while landing on the target area.
30,000/502,654 = 0.06. This means every 40 missiles launched, there will be 20 in the circle, and roughly 1 (0.06*20) will hit the carrier.
Let’s further assume that the fatal area of the carrier is not 30,000m^2, rather it is 100*50=5,000m^2. Thus, 5,000/502,654 =0.01. This means every 200 missiles launched, there will be 100 in the circle, and 1 will hit the vital spot.
A typical cost of Nimitz class carrier is 4.5billion. A Df-21 is about $0.82mil each. Catalog For simplicity, let it be 1mil each as China is becoming more costly. If PLA launch $1billion worthy of missiles (1000), 500 will be within the circle, 5 will hit the vital spot. That pretty sure is enough to make warlords cry. Economically, 1:4.5 is not a bad business, though it’s pathetic compared with our Wall Street alligators’ maneuver, but political and military impact will be far more profound than what those alligators and warlords combined can do. So actual value (to PRC) is far beyond. Thus I don’t doubt PRC may have prepared 5000 or more for carriers.
A more accurate estimation is that, the distribution of probability is normally of Gaussian type (or often called bell shaped if you attended US high school). Thus, it is more concentrating towards the center, not evenly probable withing the area. With a simple linear interpolation, the hit-target probability will be nearly doubled. So, that compansates for (if) 30% of the missiles that will eventually be shot down (it’s hard if allegedly 10 Mach is true, and I assume it may come down on to a carrier vertically or near vertically), 1000 launches can still manage to have 5 hits on the vital spot.
True that actual estimation is very complex. For instance, if the carrier is maneuvering at 15m/s (a typical Nimitz top speed), the target-seeking mechanism, the operational environment, the operators’ quality, etc. are all vital in contributing to success/failure. Frankly, many of these are top secrets on both sides. But to say no hit at all is a joke: simple high-school statistics: with increased number of experiments, the chance increases linearly. Theoretically, the probability to hit a lottery is like one that a huge meteor destroys the earth, yet people get it and the earth is still alive.
Hope it helps a little bit.
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