India tests Prithvi based ABM-3

Drevin · Post by **Drevin** » 05 Dec 2006 16:12

akutcher no one is expecting an intercept 500km away !!!!! Relax man.
Paki BM's will be in boost phase even 200km's from the tracking radar in rajasthan. Thats why I said its possible to intercept Paki BM's at boost phase. Anything wrong with that

I was trying to conclude that MIRV tech won't flow to Pakistan from China cause we canintercept in boost phase .... based on the fact that Pakistan isn't too big.
Gawd .... you made a mountain of a molehill.

akutcher · Post by **akutcher** » 05 Dec 2006 16:14

Rahul M wrote: really???
heard of the word density??

thats why i mentioned "(in air)" which means the speed is calculated at STP(25'C and 100Kpa)
irrelevant of what the density is at 50km altitude Mach numbers are given by assuming a fixed velocity which is 330m/sec

akutcher · Post by **akutcher** » 05 Dec 2006 16:16

akramas wrote:akutcher no one is expecting an intercept 500km away !!!!! Relax man.
Paki BM's will be in boost phase even 200km's from the tracking radar in rajasthan. Thats why I said its possible to intercept Paki BM's at boost phase. Anything wrong with that

Gawd .... you made a mountain of a molehill.

i am tired...... maybe my word is not that credible so pleas i request Arun_S describe to you why a boost phase interceptor is impractical

saty · Post by **saty** » 05 Dec 2006 16:29

akutcher wrote: i am tired...... maybe my word is not that credible so pleas i request Arun_S describe to you why a boost phase interceptor is impractical

As I said it would have been easier on the board if folks read something once in a while

Lalmohan · Post by **Lalmohan** » 05 Dec 2006 16:41

First law of internet forums, subclause BRF - where there shall be n or more participants in a discussion, there shall exist 2n!-pi^3 opinions on said topic. Therein 0.8n participants shall not have read the thread, 0.4n participants shall interpret it as something they were thinking about regardless of what was posted and 0.2n participants shall accuse 0.3n-j participants of being paki trolls

and so it shall be

geeth · Post by **geeth** » 05 Dec 2006 16:58

>>>irrelevant of what the density is at 50km altitude Mach numbers are given by assuming a fixed velocity which is 330m/sec

Who decided that.. you?

What is the definition of Mach Number?

saty · Post by **saty** » 05 Dec 2006 17:06

Sir, I salute you. This was work of brilliance on the lines of Newtons laws.

Question are the constants in your equation really constants, or do they change with some other factor?

i.e.are the 0.8, 0.4, 0.2 etc fixed quantity for eternity but depending on forum laws and admin strictness may vary to 0.7, 0.5 and 0.3 perhaps?

Further is the question is your statement axiomatic or can it be further deduced from some laws of physics?

Ideal (pun intended) musings on the line of rest of my posts here!!

Lalmohan · Post by **Lalmohan** » 05 Dec 2006 18:00

Saty saar, I am Baccheloge of Mathematics, University of Rawalpindi (Failed), therefore I cannot claim that my assignments of constants is harmonious with the greater order of the universe. I claim Huysenberg's principles at work here also, as well as the Universal Khan Correction Coefficient, wherein - all errors are automatically corrected by passing through the Xerox transformation (ibid)

I thank you for your kind words. btw - are you a communist drone in your spare time? I have yet to model what proportion of forum members accuse what proportion of other members of being Chicom lurkers and agents provocateurs, perhaps your data can illuminate my running dog lackey of a capitalist model?

saty · Post by **saty** » 05 Dec 2006 18:06

Saar, your credentials are impressive!! I am no commie drone Saar, although I have been accussed of droning on and on and on and on and on (excuse me) on the forum I can assure you none of my dronings are meant to be red even if they cause some forum members to see the world in that particular light. You can attribute the poor grammer of my post to lazy & fast typing and not my rare eastern origins.

I personally have been accused of being a NRI basher by one very respected individual here but I have always maintained my innocence to that count of charge.

Raja Ram · Post by **Raja Ram** » 05 Dec 2006 18:13

Just a thought for more technical adept BR forumites to comment or chew on.

Remember the KALI 2000 press reports attributed to BARC sometime around 2002 timeframe. It was supposedly based on concentrating focused Electro Magnetic radiation or some such thing to toast incomings of all kinds - missiles, aircrafts

The glitch was that the whole thing was the size of a football field or some such thing IIRC.

Now if it has been advanced enough to be fabricated and launched as a satellite, then can it be used as boost phase intercept?

Comments please

BTW I like Boost

saty · Post by **saty** » 05 Dec 2006 18:20

Raja Ram wrote: Now if it has been advanced enough to be fabricated and launched as a satellite, then can it be used as boost phase intercept?

Comments please

If I may (without being tech adept)

That is really the Star Wars model. Space based lasers to incept the missile in early phase launch. However that would still work in space part of and ICBM journey. These sats were in low earth orbit.

An additional challenge in boost phase whold be to use the laser at greater ranges since lasers would be less efficient when passing through atmosphere.

Further the the power requirements would be manifold for a reusable satellite.

And not to forget that we will have to ensure that enough sats are around to provide 24X7 cover over the hostile airspace.

So can it be done, in principle I guess sure. Will it be done in 10-20 years? I bet not.

joy_roy · Post by **joy_roy** » 05 Dec 2006 18:53

saty wrote: i.e.are the 0.8, 0.4, 0.2 etc fixed quantity for eternity but depending on forum laws and admin strictness may vary to 0.7, 0.5 and 0.3 perhaps?

sorry couldnt resist

[img][img]http://img149.imageshack.us/img149/6354/dgfsdgzk0.png[/img][/img]

Arun_S · Post by **Arun_S** » 05 Dec 2006 21:36

akutcher wrote:
geeth wrote:>>>It is: Mach 6.44 (2.12km/sec)

Did you consider the local velocity of sound at 50 KM?
Dude he dint consider anything
the speed of sound is 330m/sec or 0.33km/sec(in air).... there is nothing to assume

Geeth: Yes the ROCKSIM models atmospheric pressure, temprature and density change for atmosphere upto 90Km altitude.

akutcher: He heee I only an old bafoon on BR (bhery zimple), you are the wiseman as your posts speak of the intellect.

speed of sound is 330m/sec or 0.33km/sec(in air).... there is nothing to assume

Wrong. Speed of sound in air is NOT constant. It changes per altitude.

The calculation took into account local atmospheric property at 50Km altitude (which happens to invert at certain higher altitude); the sonic speed is 330m/second temperature -2.5 degree C. You see all drag equations use Mach number, thus to determine Mach number atmospheric properties are modeled in the software, there is no two ways about computing drag.

akutcher · Post by **akutcher** » 05 Dec 2006 21:50

i only referred to u to say that u are correct

speed of sound is obviously varies with density but if mach is not fixed for calculating mach numbers, does that means when we say the speed of an aircraft is mach2.2 at an altitude of 15km we are correcting the value of 1mach for that altitude?

Arun_S · Post by **Arun_S** » 05 Dec 2006 21:50

akutcher wrote:
Rahul M wrote: really???
heard of the word density??
thats why i mentioned "(in air)" which means the speed is calculated at STP(25'C and 100Kpa)
irrelevant of what the density is at 50km altitude Mach numbers are given by assuming a fixed velocity which is 330m/sec

Please spare us all this comedy please

. I will die laughing. Please limit such posts to humor thread.

Please think for 2 minutes to rationalize you thoughts before posting on this thread and that will spare this forum of the raw mental waste. Seriously.

Please understand this thread is for serious discussion.

Arun_S · Post by **Arun_S** » 05 Dec 2006 21:52

akutcher wrote:speed of sound is obviously varies with density but if mach is not fixed for calculating mach numbers, does that means when we say the speed of an aircraft is mach2.2 at an altitude of 15km we are correcting the value of 1mach for that altitude?

Yes.

Raj Malhotra · Post by **Raj Malhotra** » 05 Dec 2006 22:44

Arun thanks for your answer.

Incidentally if I may ask, are you working on new estimates of parameters of PAD and AAD after so much info has come to light, or are your previous estimates meet the public info?

Raj Malhotra · Post by **Raj Malhotra** » 05 Dec 2006 22:47

Also as per links above, Saraswat has offered no hint that liq stage will be replaced by solid stage but in fact some reports claim justification for their use, So I hope that the liquid stage thingie does not become a permanent feature?

Vivek K · Post by **Vivek K** » 05 Dec 2006 23:10

Pardon my ignorance but does a liquid engine provide more control over the missile than a solid motor?

Dileep · Post by **Dileep** » 05 Dec 2006 23:18

Alok_N wrote:Thanks, Dileep. That helps a lot. The "phase" that I was talking about had to do with transmission distances, because I was (incorrectly) assuming that a triangulation was involved ... from what you have written it would appear that some sort of a "sweep" is used ... the polarization approach is good, but ultimately what limitss the angular resolution? ... I am not clear as to why it is superior to triangulation ...

Also, if a triangulation is used in the Doppler measurement also, then 3 components of the velocity are measured ... this will helps in trajectory calculations as well ... comments?

Triangulation works better, but it is a whole different technology. To begin with it needs three seperate, but coordinated sources. Secondly, there is a remarkable difference when you triangulate YOUR position based on RECEIVED signals from three sources (like GPS) in contrast to triangulate a TARGET's location based on REFLECTED signals. In the second case, you got to network locations vastly seperated.

The angle of a target is measured by measuring the beam angle. In a mechanical system that is done by encoders. In ESA, the computer knows the beam angle. Add to this the uncertainity of the beam tracking and you will get a picture of what kind of precision we are working with.

Coming to range measurement, the precision there is in terms of several tens wavelengths of the carrier. You need enough number of cycles for the detector to sync, detect the pulse and detect the freq and phase shifts.

Lalmohan · Post by **Lalmohan** » 05 Dec 2006 23:30

I can see that the Researj Depaaarment of the University of Rawalpindi Mathematix Wing will have to shortly release papers on basic aero and thermo dynamics for all readers. I believe that in Djinn mechanics, the velocity related to Mach number remains fixed at all altitudes, thereby allowing herrowic acts such as the K8 zerrow forward velocity.

now at last all is becoming klear onlee!

John Snow · Post by **John Snow** » 05 Dec 2006 23:33

Vivek K wrote:Pardon my ignorance but does a liquid engine provide more control over the missile than a solid motor?

No ca not do that . Use a tool called google and find out otherwise your membership to BRF will be levied a tax !!!

Relax and learn by googling

to help you ease into orbit

here http://en.wikipedia.org/wiki/Rocket_fuel

Alok_N · Post by **Alok_N** » 05 Dec 2006 23:40

Dileep wrote:Triangulation works better, but it is a whole different technology. To begin with it needs three seperate, but coordinated sources. Secondly, there is a remarkable difference when you triangulate YOUR position based on RECEIVED signals from three sources (like GPS) in contrast to triangulate a TARGET's location based on REFLECTED signals. In the second case, you got to network locations vastly seperated.

there are several approaches ... for example, the 3 sources could work on 3 different frequencies ... then a single receiver could triangulate ... else, the 3 signals could be encoded ... communications issues should not pose a problem either ... the only drawback I see is a military one ... if the enemy takes out one of the 3 stations, the system is dead ... in the present model there could be 3 independent stations for redundancy ...

The angle of a target is measured by measuring the beam angle. In a mechanical system that is done by encoders. In ESA, the computer knows the beam angle. Add to this the uncertainity of the beam tracking and you will get a picture of what kind of precision we are working with.

I suspect that encoders can be quite good ... 1 milliradian should be easily achieved ... is that good enough? ... at a distance of 100 Km, that would be a 100 m error in target position ... I suspect that a few 10s of microradian accuracy is needed ... at that level, errors in gears would probably dominate (do I hear CNC?) ... if the angle is derived by the computer driving the system (some sort of step motor), then it is surely the gears that dominate ... perhaps a feed-back system between the computer and encoders is what is used for greater accuracy?

Coming to range measurement, the precision there is in terms of several tens wavelengths of the carrier. You need enough number of cycles for the detector to sync, detect the pulse and detect the freq and phase shifts.

I can see why 10s of wavelengths are required for Doppler measurement ... however, I would think that the primary telemetry could be done with less than 10 cycles ... what am I missing?

Dileep · Post by **Dileep** » 06 Dec 2006 00:05

Alok_N wrote: there are several approaches ... for example, the 3 sources could work on 3 different frequencies ... then a single receiver could triangulate ... else, the 3 signals could be encoded ... communications issues should not pose a problem either ... the only drawback I see is a military one ... if the enemy takes out one of the 3 stations, the system is dead ... in the present model there could be 3 independent stations for redundancy ...

Correct. But the essence is, you need three different, geographically seperated, synchronously timebase coded signals transmitted towards the target. a receiver at ANY suitable location that receives the reflected signal can do the triangulation.

BUT, you need the antennas of ALL those devices pointed at the same target at the same time. Hm...

I suspect that encoders can be quite good ... 1 milliradian should be easily achieved ... is that good enough? ... at a distance of 100 Km, that would be a 100 m error in target position ... I suspect that a few 10s of microradian accuracy is needed ... at that level, errors in gears would probably dominate (do I hear CNC?) ... if the angle is derived by the computer driving the system (some sort of step motor), then it is surely the gears that dominate ... perhaps a feed-back system between the computer and encoders is what is used for greater accuracy?

The ESA is electronic phased scanning. No mechanicals involved. Anyways, being a Chair Marshal, I can't figure out how the beam inaccuracy and measurement(encoder and related) compare in terms of relevance.

I can see why 10s of wavelengths are required for Doppler measurement ... however, I would think that the primary telemetry could be done with less than 10 cycles ... what am I missing?

You need to make sure that the pulse is indeed a reflection of your own transmitted signal. It may be possible to do a phase match within 10 cycles if you have good signal, given the DSP capabilities.

Alok_N · Post by **Alok_N** » 06 Dec 2006 00:21

Dileep wrote:The ESA is electronic phased scanning. No mechanicals involved.

Thanks. Time for reading ...

Mort Walker · Post by **Mort Walker** » 06 Dec 2006 03:32

Using mechanical gears and synchros it is possible to get an accuracy of 0.1 degree for a large antenna (~10 diam). Of course, if you could do this electronically its much better than having periodic mechanical faults.

Alok_N · Post by **Alok_N** » 06 Dec 2006 03:41

Mort Walker wrote:Using mechanical gears and synchros it is possible to get an accuracy of 0.1 degree for a large antenna (~10 diam).

surely you can do better than that ... using 1980's technology, I have worked with a system that moved a 6m frame with an accuracy of 0.05 deg ... things should have improved a lot by now ... of course, it also depends on the desired speed of movement ...

SaiK · Post by **SaiK** » 06 Dec 2006 03:42

what i am concerned is the RAM coated missiles or c/si-composite heat shields, that would not deflect radar waves back to the origin. i know, its not important now, but it would become important pretty soon. stealth missiles is what chinks and pakis will seek to attack our ABMs.

btw, what are the long ranged IRST available.. and how big and large and long it can detect, track, and engage? how applicable are these for ballistic missiles that are coming at you at >15g?.

we have 30 seconds to do all these to the target at 500kms away in the exosphere. btw, does boost phase, include thermosphere and mesospheres? i would like to kill it the enemy in the exosphere.. more safer for the earthians (not pakis/chinkis/roaches).

and, what are the effects of hitting a 10kt nuke in the in the stratos or mesos?

ramana · Post by **ramana** » 06 Dec 2006 03:47

Any takers for a thread where members can ask questions and hope to get answers sort of Mil tech nukkad thread?
I am tired of oraclaized querrys in the thread.

I also wish we had post numbers so replies can be seen in context.

Mort Walker · Post by **Mort Walker** » 06 Dec 2006 03:47

You probably can do better than 0.1 degree. In radio telescopes and sat. trackers they are better, but for radar applications when you move an antenna in az/elev at fast speeds, it leads to many many mechanical problems. Hence the reason, many systems are now going to electronically scanned antennas or at least elev. is electronically scanned to reduce the mechanical issues.

Ananth · Post by **Ananth** » 06 Dec 2006 03:55

ramana wrote:Any takers for a thread where members can ask questions and hope to get answers sort of Mil tech nukkad thread?

I second general miltech nukkad thread. But for radar etc we already have this

Arun_S · Post by **Arun_S** » 06 Dec 2006 04:02

Raj Malhotra wrote:Arun thanks for your answer.

Incidentally if I may ask, are you working on new estimates of parameters of PAD and AAD after so much info has come to light, or are your previous estimates meet the public info?

I woudl like to but I am tied up with prior commitments, but will try to get it on BR Missile page in a month. For now I am chasing a deadline for next issue of IDR("India Defense Review"). It will be eye popping stuff.

Arun_S · Post by **Arun_S** » 06 Dec 2006 04:13

ramana wrote:Any takers for a thread where members can ask questions and hope to get answers sort of Mil tech nukkad thread?
I am tired of oraclaized querrys in the thread.

Please please please.

Dileep · Post by **Dileep** » 06 Dec 2006 04:49

ramana wrote:Any takers for a thread where members can ask questions and hope to get answers sort of Mil tech nukkad thread?

Votes Yay

shiv · Post by **shiv** » 06 Dec 2006 06:16

ramana wrote:Any takers for a thread where members can ask questions and hope to get answers sort of Mil tech nukkad thread?
I am tired of oraclaized querrys in the thread.

I also wish we had post numbers so replies can be seen in context.

ramana - we used to have a miscellaneous question thread for a long time. Call it what u liek - butthe idea is a good one

Sumeet · Post by **Sumeet** » 06 Dec 2006 06:27

the mil tech nukkad idea is good as long as some decency is maintained meaning the thread doesn't becomes a collection of chinese and puki military equipment bashing.

SaiK · Post by **SaiK** » 06 Dec 2006 07:12

sorry to have asked a nukkad question.. just wanting to know how Dr. Oracles solomonize thoughts in BR. i am all eager to see the "Mil Tech. Nukkad" Thread.

rakall · Post by **rakall** » 06 Dec 2006 09:46

What is going on with this thread??

For the first time in a long time DRDO has done something absolutely out-of-the-blue and wonderful by revealing two AD projects -- giving the jingos to cheer a lot and have meaningful discussion..

but we are just wasting this thread.. now I fully understand why Singha keeps cribbing about oraclization of BR..

just to give some of the newcomers a feeling of what is in BR -- I spent whole one-and-a-half years lurking in BR (info pages as well as forum) before i registered.. Please take a look around all the pages, discover the old MRCA & Su30 threads in trashcan archive and understand the quality, weight and passion in those discussions..

read and google a lot before jumping the gun and star posting.. sometimes our intuition could be very wrong.. it is very appalling that some people who claim to be jingos (if you register at BR - you are claimig to be one) dont even know what WingsOfFire is, let alone reading it.. berry berry sad..

I am no trying to sermonize anyone, but this is a plea for all newcomers to be less quick off the trigger and take time to read a lot - BR as well as google..

lets not get into a situation where we will have to setup a questionaire for people seeking registration.. like

1. what is IGMDP?
2. What is 'wings of fire'?
3. How long have you been reading BR?
4. Who is the author or BR missile page?
5. Who is Admiral Rakesh?
6. What is Farce? etc etc

Kanson · Post by **Kanson** » 06 Dec 2006 10:17

SaiK wrote:what i am concerned is the RAM coated missiles or c/si-composite heat shields, that would not deflect radar waves back to the origin. i know, its not important now, but it would become important pretty soon. stealth missiles is what chinks and pakis will seek to attack our ABMs.

btw, what are the long ranged IRST available.. and how big and large and long it can detect, track, and engage? how applicable are these for ballistic missiles that are coming at you at >15g?.

we have 30 seconds to do all these to the target at 500kms away in the exosphere. btw, does boost phase, include thermosphere and mesospheres? i would like to kill it the enemy in the exosphere.. more safer for the earthians (not pakis/chinkis/roaches).

and, what are the effects of hitting a 10kt nuke in the in the stratos or mesos?

Hi SaiK, If I can answer some of your questions.

btw, does boost phase, include thermosphere and mesospheres?

Altitude reached by the BM depends upon the burntime, speed and the firing anlge. People sometimes playfully say an ICBM can be used for a target some 100km away. i.e. instead of firing in normal ballistic angle ~45 deg, if fired more straighter, height reached by the BM can go up(sometimes called as lofted trajectory).

what i am concerned is the RAM coated missiles or c/si-composite heat shields, that would not deflect radar waves back to the origin. i know, its not important now, but it would become important pretty soon. stealth missiles is what chinks and pakis will seek to attack our ABMs.

RAM coated can help in reducing in RCS. But will i able to mask completely is the question ? We can recollect the news from US/Japan talked about the complete tracking of Topol-M for the full range by their X-band radars. Infact they have spoke about lot of valuable data collected through their X-band radars from this test. Dont know whether russians used RAM coated RV/Warhead or not in these tests. Russians adding more emphasis on zig-zag manoeuverability of Topol-M as defence against ABM during the mid-course flight can be seen in this context.

Little info is available in public domain about X-band radars. Sameway as US hide the info about APG-77, they can also do it to X-band. Eventhough X-band can give good converage, the problem is it has to stationed within your borders or to be floated in sea like SBX. Here, you cannot get a global coverage; your radar coverage is limited by the no. of land based radars and its placement across the land mass. Further, the problem is heightened by SLBM. So one cannot say, US is not working in such a project for space based tracking. If we talk about ground clutter, this applies for AWACS too. By this, are we going to say AWACS is less efficient than land based one. There are better technologies and software available to negate the ground based clutter. Here, we are more interested in object moving in space during mid-course flight and not the one moving near to ground.

what are the effects of hitting a 10kt nuke in the in the stratos or mesos?

You can expect radiation debris.

To all new BRites: What information available in open is very limited and is mostly through second-hand. Little to say about their authenticity. Hope you guyz consider this before engaging in heated dicussion and taking sides.

Before me signing off, Xmas wishes to everyone.

SaiK · Post by **SaiK** » 06 Dec 2006 10:24

kanson, thanks but no thanks., lets abide by BR. don't worry about answering, that i shall google to know more, or nothing is fine too. lets get back to the topic of discussion. cheers.