Is there anything remotely related to technical discussion in your post, because I've failed to detect it. Life reject such as yourself obviously felt butthurt enough to start fatansizing about laser weapons that are still under testing. On the other hand, DF-21 is already widely deployed. If you're going to go down that route, might as well go all the way. Maybe I could post you link to discounted tissues so you can cry your issues out. No wait, go smoke some weed which you Vietnamese are known to grow. Before you cry racism, my post is simply an emulation of yours.
When you're done trolling, look up 钱学森弹道 if you want to learn about DF-21. Hell, I've even taken the trouble of finding the articles for you. Provide your own translation.
http://paper.dic123.com/keywords_5038155006/
???????????????--??????2003?01? - ?? - ?? - ???? - ?? - ??? - ???????
That is a big laugh...
...You talk as if this has not been 'discussed' before and that I made no comments about it. And I used the word 'discussed' very generously about the Chinese members' postings.
But...Do not read Chinese and as you wish...This is what I posted a long time ago in another debate about the DF-21...
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1- The latest variant of the DF-21 has reaction thrust steering mechanisms. The radar system is high PRF X-band with a scan limit of 60deg. due to nosecone dimension. Since the target is moving, proportional navigation is employed to provide continuous target track. Despite the fact that the target is moving at only 33 knots, the PN guidance output is then converted to bang-bang guidance commands to provide the vehicle with near instant lateral acceleration to reduce interception probability by air defense missiles. Due to vehicle structural constraints, bang-bang guidance commands are limited to 10g. Standard fighter aircraft air to air missiles, because of their smaller warhead, can have bang-bang guidance forces up to 40g with no catastrophic structural failure.
2- Given the developmental maturity of ballistic defense missile system like the latest US SM-3, it is determined that the best execution altitude for vehicle deceleration for evasive maneuvers to be at 25 km above ground level (AGL). The longer the vehicle remains static, it will provide air defense radars with consistent vehicle profile and descent rate, also with the lower altitude, the higher air density would not allow the 10g evasive maneuvers, therefore the greater the odds of a successful interception. Further, this 10g bang-bang guidance limit is necessary to prevent the vehicle's radar system from losing target line-of-sight (LoS).
3- If this vehicle is used against fixed land targets that has air defense deployments, the vehicle can afford to lose target LoS with higher g-rating evasive maneuvers as target geo-coordinates are also fixed in memory. The vehicle will remember heading offset and deviation rate and can make appropriate return bang-bang guidance commands for the radar to reacquire target information. Against a moving target, even though one moving at only 33 knots, the current technology level does not afford the vehicle to lose a moving target LoS.
4- The latest US SM-3 missile is capable of reaching speed of 9600km/h with a climb rate of 5km/h in altitude, making early descent phase evasive maneuvers important to reduce interception probability. Missile against aircraft engagements typically occurs at or below 10km altitude, making feasible aerodynamic forces exploitation. But because this vehicle will begin to execute evasive maneuvers at very thin air altitude that reduces aerodynamic forces exploitation effectiveness, reaction thrust mechanisms are necessary and this will cost vehicle warhead payload.
5- During development, in post evasive maneuvers analysis, an interface was thought to be required between bang-bang to proportional navigation guidance. Velocity compensated proportional navigation guidance (VCPN) was briefly tested as that interface and but was found to offer statistically negligible improvement in target tracking and guidance. Target lead angle and its rate change are nowhere as extreme as in a missile versus aircraft engagement and any vehicle descent rate change is already reflected in closing speed calculations. Therefore, it was decided to use only proportional and bang-bang navigation guidance methods.
6- Another developmental exploration was the order of guidance laws. The program decided to conduct dual testings. One strategy was bang-bang guidance for initial vehicle-target orientation, evasive maneuvers, then switches to PN guidance at 2km AGL. A parallel strategy has the reverse, PN for initial vehicle-target orientation and bang-bang guidance for evasive maneuvers. It was found that because bang-bang guidance is already sensitive to LoS change and rate of change, hardware related LoS noise can induce evasive maneuvers thrust command oscillations as the guidance laws attempt to null the LoS rate after every execution. This condition is similar to constantly oversteering an automobile, either due to driver ability or steering mechanism 'slop'. When PN guidance takes over at 2km AGL, the program recorded a higher miss rate than the pn_bang-bang strategy. In some instances, the vehicle's radar could not reacquire the target after several violent maneuvers to evade air defense missiles.
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What I said above is only a speculation on how a Chinese government explanation
COULD go. Even if I am %100 wrong, I would be wrong only about the DF-21, not the basic principles on missile guidance contain therein. People could use keywords searches for themselves to see if those principles are made up or not.
For examples...
Proportional navigation - Wikipedia, the free encyclopedia
Proportional navigation (PN) (Pro-Nav) is a guidance law used in some form or another by most homing air target missiles. It is based on the fact that two vehicles are on a collision course when their direct Line-of-Sight does not change direction. PN dictates that the missile velocity vector should rotate at a rate proportional to the rotation rate of the line of sight (Line-Of-Sight rate or LOS-rate), and in the same direction.
GBU-12 Paveway II - Wikipedia, the free encyclopedia
Paveway II laser guided bombs use what is known as "bang bang" guidance. This means the bomb's fins deflect fully, rather than proportionally when it is attempting to guide to the laser spot. For example, if it sees the laser spot and determines that it should make a change it deflects its fins until it has over-corrected and then it deflects back the opposite direction creating a sinusoidal type of flight path. This type of guidance may be less efficient at times.
Proc IMechE, Part G: Journal of Aerospace Engineering - Hybrid guidance law for interception of ballistic targets
Abstract
This article develops a new integrated missile guidance scheme against ballistic targets based on optimal control theory and neural network technology, in which an optimal midcourse guidance law is analytically derived to reach a near head-on interception engagement. This enables an aerodynamically controlled missile to successfully intercept a very high-speed target. A multi-layer feedforward neural network is incorporated with proportional navigation guidance in the terminal guidance section to adaptively enhance missile agility and to correct acceleration commands in response to rapid changes in aerodynamics and target manoeuvres. The entire defensible volume in three-dimensional space is characterized and the missile performance robustness is verified.
As you can see in the sample preview from the above source, the authors' names are not Anglo-Saxon, I believe those names are of Asian origins, I could be wrong about that so am open for correction, and the article speaks of hybrid navigation and guidance laws for missile interception schemes. That mean my speculation with the DF-21 using a hybrid PN/bang-bang guidance laws has genuine engineering foundation, even if I am wrong about that hybrid scheme in the DF-21 itself. As a significant note, in radar detection, based upon the behaviors of the object, we can deduce what kind of navigation/guidance scheme we are seeing and therefore what kind of weapon is coming.
If the Afghan military made a claim about their version of the DF-21, we would have a good laugh. If the Iranians made the same claim, we would take it a wee bit more seriously and gather up some intelligence to verify the validity of that claim. But since it is made by the Chinese, and given what we know of Chinese technology level overall, we will take the claim much more seriously and look for any kind of technical presentation for public consumption similar to how I speculated above. We have seen none. That does not mean the Chinese government is somehow obligated to made such a technical presentation but given the lack of actual field testing it also imply that the DF-21 may be not as capable as the Chinese government would have everyone believe. You Chinese boys demand that any US weapons development be fully tested under 'real world' conditions immediately while exempting the Chinese military from the same. As someone who has relevant experience I call it as I see it: ignorant.
If the DF-21's project leader give the world a technical blurb similar to what I speculated above, have no doubt the US would be all over it, analysts would give China hearty praises and I would agree with them. The relevant keywords would perk up weapons designers everywhere. Weapons engineers would know that while no secrets are disclosed, the foundational principles contain within are applicable to all: US, China, Russia...Everyone. As long as they have the technical capability to exploit those principles, they can attempt to develop their versions of the DF-21. What I speculated above there are plenty of people with much more experience and tools available to them to make even more in-depth speculations about the DF-21. So have no doubt that we know that to look for and how to counter it.
IF its claimed capability is real.
Ultimately, everyone is a 'fanboy' because each is a patriot to our countries of allegiance. But there is a world of difference between blind blather and regurgitation of governmental propaganda versus genuine polite technical explorations of the things military that attract our attention. You Chinese boys are terrified of the latter. If anyone ask for elaborations on any paragraph in my speculation, when I am done he will see that even though I may be wrong about the DF-21 -- that it exist and that it employs different mechanisms to achieve its capability -- the questioner will gain a much better understanding of the principles involved and he may even speculate for himself. None of you conscript rejects can do the same for this thing that you support while I can credibly support my challenges and that is the source of your hostility towards me.
So translate your sources and let the readers see who is the more credible one.
