Indian Missile Technology Discussion

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Nitesh
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Re: Indian Missile Technology Discussion

Post by Nitesh »

kobe wrote: - Mushi butt recognition will be used (if available)
:rotfl: :rotfl: :rotfl: :rotfl:

which algorithm does this?
Austin
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Re: Indian Missile Technology Discussion

Post by Austin »

kobe wrote: there is nothing contradictory,

"we don't depend on GPS" could very well mean:

- GPS will be used (if available)
- GLOSSNASS will be used (if available)
- IRNSS will be used (if available)
- Cellphone Triangulation will be used (if available)
- Mushi butt recognition will be used (if available)
Yeah but the news report from Hindu and other talks of GPS , and even the previous failures are attributed in some part to GPS going bad.

But in context of the current test , we need to be clear either GPS was used which means Dr Pillai statement was incorrect or it was not used , which means the previous failure of INS error or the current success has nothing to do with GPS signal.
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Re: Indian Missile Technology Discussion

Post by rakall »

Austin wrote: Yeah but the news report from Hindu and other talks of GPS , and even the previous failures are attributed in some part to GPS going bad.

But in context of the current test , we need to be clear either GPS was used which means Dr Pillai statement was incorrect or it was not used , which means the previous failure of INS error or the current success has nothing to do with GPS signal.
This is what I got from 3 different people I talked to at Brhamos pavilion at AI09 - consistently they all mentioned..

Brahmos uses GPS/Glonass for INS correction.. But the first test failure had nothing to do with GPS.. The test was conducted at a 50km range - INS (which is pretty accurate) at the 50km range would be very accurate... the error "if any" at that range would be too small to require significant GPS correction..

The failure was with the new algorithm which had to find a target among a cluster of targets with similar RCS..

Have your pick of what to believe..


Added later:

- All the terminal manuering that the missile does is simply pre-programmed.. it does not make any decision anything on its own once fired..
- so the basic philosophy is that we always have the target & surroundings co-ordinates/picture from UAV or Recce flights or Satellite pics (remember Cartosat-2 can make 3D maps) ..
- If different way points are pre-programmed - then the waypoints are executed in the horizontal plane if such space is available (esp if that happens at higher altitude - no problem at all bcoz no obstructions)..
- If an S-curve has to be executed near the target - it is preprogrammed and such a maneuvere happens in the horizontal plane only if sufficient space is available.... ( estimate the turn radius reuired at the high-speed; if such space is available without obstructions)..Obviously this is in case of targets that are isolated, defended and an S-curve is required to overcome defenses or maximise impact..
- if the target is in a densely populated area - obviously maneuering in horizontal plane may not be possible; In which case the missile will descend to the lowest possible altitude close to the target.. and do a top-attack.
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Re: Indian Missile Technology Discussion

Post by Austin »

rakall wrote: Brahmos uses GPS/Glonass for INS correction.. But the first test failure had nothing to do with GPS.. The test was conducted at a 50km range - INS (which is is pretty accurate) at the 50km range would be very accurate... the error "if any" would be too small to require significant GPS correction..

The failure was with the new algorithm which had to find a target among a cluster of targets with similar RCS..

Have your pick of what to believe..
Rakall , I believe in what those guys say.

1 ) Brahmos might be using GPS/GLONASS to get an initial fix of launcher position , this is for conditions where the launcher is always on the move ( could equally be ships and submarines ) , once the initial fix is obtained , for the rest of its flight it depends on INS based navigation with no GPS inflight updates , more ever the time of flight for the full range is so short that the INS error if at all if negligible , and the MMW radar can guide the missile to its target.

2 ) The failure of the algo is an acceptable answer , what is not acceptable is no new seeker , for all practical purpose it will be a MMW seeker which can discriminate a small insignificant target among a cluster of targets.

A MMW seeker though is limited on range i.e. ~ 5 to 10 km , but typical MMW seekers FMCW type with a bandwidth of 500 MHz and a range resolution of 30 cm , high range resolution is possible with MMW seeker , which will help in detection of small stationary or ground slow moving targets or even target based on known RF signatures , all in all perfect for what DRDO claims for Brahmos Block II
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Re: Indian Missile Technology Discussion

Post by Austin »

- All the terminal manuering that the missile does is simply pre-programmed.. it does not make any decision anything on its own once fired..
What if the target moves from position x to position y ? you can only do pre-programmed trajectory and
manouvering if the target is stationary and whose co-ordinates are known , some thing even a Brahmos Block 1 may do as well
so the basic philosophy is that we always have the target & surroundings co-ordinates/picture from UAV or Recce flights or Satellite pics (remember Cartosat-2 can make 3D maps) ..
Again good for stationary targets , if you want to take down a moving TEL or even smaller moving objects, you need to have a MMW seeker which can discriminate the target in the clutter and hit it.

Well getting a real time information on such targets is again not easy , that would either make or break the block 2 true potential in real war , IMHO
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Re: Indian Missile Technology Discussion

Post by rakall »

Austin wrote:
rakall wrote:
The failure was with the new algorithm which had to find a target among a cluster of targets with similar RCS..

Have your pick of what to believe..
Rakall , I believe in what those guys say.

..
I did not mean it that way.. it was not meant at anyone..

The news reports indicate a GPS-fix to todays test.. but that was not what I heard at AI09.. I simply meant to say - people can have their pick of either one unless we get concrete evidence..

Dint direct it at you - just in case, you felt so.

Austin wrote:
1 ) Brahmos might be using GPS/GLONASS to get an initial fix of launcher position , this is for conditions where the launcher is always on the move ( could equally be ships and submarines ) , once the initial fix is obtained , for the rest of its flight it depends on INS based navigation with no GPS inflight updates , more ever the time of flight for the full range is so short that the INS error if at all if negligible , and the MMW radar can guide the missile to its target.

..
The Brahmos guys specifically mentioned that GPS is used for correction of INS..

The launcher is always in tandem with the command center which feeds the target and the path the missile should take.. if GPS is just to get initial co-ords of launcher -- why not have a GPS module in the control center which automatically feeds it along with the targets & flight path to the missile... Even a module attached to the launcher can pass the exact GPS fix to control center and control center can feed that along with the targets & flight path to the missile
Austin wrote:
2 ) The failure of the algo is an acceptable answer , what is not acceptable is no new seeker , for all practical purpose it will be a MMW seeker which can discriminate a small insignificant target among a cluster of targets.

..

I specifically asked if there was an mmw or SAR or ElOp seeker.. They said " it is not so simple to replace the seeker inside.. there is not much space in the nosecone which is fairly small "

Which probably means the mmw or SAR seekers that can replace the existing RF seeker are probably over-sized compared to the exisiting one..

They also added that a new RF seeker is in JV development.. but did not mention any mmw or SAR - after repeated questions, the reply was only negative about the mmw/SAR. Further - the INS will also be upgraded to RLG's soon.

Austin wrote:
A MMW seeker though is limited on range i.e. ~ 5 to 10 km , but typical MMW seekers FMCW type with a bandwidth of 500 MHz and a range resolution of 30 cm , high range resolution is possible with MMW seeker , which will help in detection of small stationary or ground slow moving targets or even target based on known RF signatures , all in all perfect for what DRDO claims for Brahmos Block II
At 5-10km range and a flightspeed near Mach3 - does the missile have enough time to detect, change course and home-in?

I dont know how it works out for the LACM version.. but atleast while discussing the anti-ship version (more specifically possibility of Anti-AWACS role), one guy mentioned that seeker opens out at distance of 40km (IIRC) which is less than 45secs before impact.. It has to be that far-out for seeker to open bcoz the ship would have been moving since the missile is fired - the seeker has to loacte the target, identify it, change direction and home-in within 45secs or less..

Not claiming what I say is "the truth".. But just sharing what I was told..
Last edited by rakall on 05 Mar 2009 17:59, edited 1 time in total.
rakall
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Re: Indian Missile Technology Discussion

Post by rakall »

Austin wrote:
- All the terminal manuering that the missile does is simply pre-programmed.. it does not make any decision anything on its own once fired..
What if the target moves from position x to position y ? you can only do pre-programmed trajectory and
manouvering if the target is stationary and whose co-ordinates are known , some thing even a Brahmos Block 1 may do as well
so the basic philosophy is that we always have the target & surroundings co-ordinates/picture from UAV or Recce flights or Satellite pics (remember Cartosat-2 can make 3D maps) ..
Again good for stationary targets , if you want to take down a moving TEL or even smaller moving objects, you need to have a MMW seeker which can discriminate the target in the clutter and hit it.

Well getting a real time information on such targets is again not easy , that would either make or break the block 2 true potential in real war , IMHO

- Obviously in case of ship - which is slowly moving, the missile opens it seeker in the vicinity to detect the target, identify and change course.. therefore it has to open the seeker out at a distance (~40km) so that the target falls within the scan angle of the seeker - even if it has moved from its intitial position..

there is no clutter problem in case of ship..

- the way points programmed are to improve survivability of missile.. just in case..
- Or "S-curve" waypoints/maneveribility is useful in case of ships or stationary targets to "go behind" and hit - if that maximises damage..

- For the Army version, I think, the targets would generally be stationary targets.. Definitely not fast mvoing targets like tanks or convoys.
- Mk1 for Army was meant to hit a high RCS target against backdrop of non-RCS targets (stationary).. Lets say radar sites or Batallion command centers which are fixed targets..
- Mk2 can hit a target among a backdrop of similar RCS targets (stationary).. Lets say Leadership targets in cities..

if you notice the Army tests in Pokhran or LACM test from sea-to-land --- all of them were done with stationary targets.. Where as atleast one anti-ship test was done with a moving ship..

PS:
If you remember - Before AI09 I had posted this crazy idea of possibly using Brahmos as AWACS killer.. I had discussed this idea with the Brahmos folks and that is where all the above minute details were explained.. It wont work as AWACS killer bcoz when the missile comes in the vicinity and opens its seeker -- the plane wont be there.. Same probably for fast-moving targets like tanks, TELs or convoys..

Neither can Tomahawk do that.. can it? Thats not the role for cruise missles.. that kind of role is probably for some PGM dropped from Rustom..
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Re: Indian Missile Technology Discussion

Post by Austin »

rakall wrote: I did not mean it that way.. it was not meant at anyone..

Dint direct it at you - just in case, you felt so.
Ofcourse not at all , nothing personal here , I must have put it in a wrong way , my bad , sorry.
rakall wrote:The Brahmos guys specifically mentioned that GPS is used for correction of INS..
So Brahmos Block 2 missile carries a GPS receiver ?
The launcher is always in tandem with the command center which feeds the target and the path the missile should take.. if GPS is just to get initial co-ords of launcher -- why not have a GPS module in the control center which automatically feeds it along with the targets & flight path to the missile... Even a module attached to the launcher can pass the exact GPS fix to control center and control center can feed that along with the targets & flight path to the missile
Ok if Brahmos guys have mentioned that GPS is used for correction of INS inflight , then we *do* use GPS for sure , as opposed to what Dr Pillai has to say.

Yes that is what I meant when I said initial GPS fix , I meant from the Command Center to the missile for initial launch data , did not mean the missile itself carried GPS receiver for initial fix.
I specifically asked if there was an mmw or SAR or ElOp seeker.. They said " it is not so simple to replace the seeker inside.. there is not much space in the nosecone which is fairly small "
Well a MMW seeker is small enough to fit into the nose of anti-tank missile , thats the USP of MMW seeker , small , high resolution ,high discrimination, all weather capability , making it ideal for Fire and Forget type and terminal homing scenario , even signature matching based on known RF signature of target is possible.
Which probably means the mmw or SAR seekers that can replace the existing RF seeker are probably over-sized compared to the exisiting one..
I dont think it should be any larger than the current X band Antenna that Brahmos 1 has , in worst case as small as the current antenna.
They also added that a new RF seeker is in JV development.. but did not mention any mmw or SAR - after repeated questions, the reply was only negative about the mmw/SAR. Further - the INS will also be upgraded to RLG's soon.
RLG is good as the navigation error will be minimal , all the more reason we dont need any external GPS type signal , if we get its good , if we dont its good as well.
At 5-10km range and a flightspeed near Mach3 - does the missile have enough time to detect, change course and home-in?
The flight speed should be ~ M 2 at 10 m and ~ M 2.8 if high altitude profile , well the idea is to take the missile as close to the target by means of INS and then the seeker do the final terminal homing based on the pre fed signature of the target , if one needs to attack a small target one needs high resolution image of the target under attack or a +ve way to discriminate it amongst clutters.
I dont know how it works out for the LACM version.. but atleast while discussing the anti-ship version (more specifically possibility of Anti-AWACS role), one guy mentioned that seeker opens out at distance of 40km (IIRC) which is less than 45secs before impact.. It has to be that far-out for seeker to open bcoz the ship would have been moving since the missile is fired - the seeker has to loacte the target, identify it, change direction and home-in within 45secs or less..
Much similar here , only the seeker may get activated at 10 Km , the target here is far cluttered and much smaller than a ship at sea and in cases will be moving slowly (TEL) , hence far more challenging and yes one can call it exotic feature.

I dont think one needs any complicated S shape manouver to attack a land target , because flying low at 10 m is itself a challenging target to detect at those speed , even a Top Attack while terminal homing is good.

With the normal X band seeker we can get those range , but target discrimination and heavy clutter is not something an antiship missile will face , hence a Brahmos block 1 ability to hit radio contrast land target.

About MMW range being ~ 8 to 10 Km is from open literature , may be Arun can add on the range part of MMW seeker.
not claiming what I say is "the truth".. But just sharing what I was told..
Well we are just here to share and learn from each other , and your Aero India coverage was quite commendable and excellent :)
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Re: Indian Missile Technology Discussion

Post by rakall »

Austin wrote: So Brahmos Block 2 missile carries a GPS receiver ?
Well does it carry a GPS reciever or GLONASS reciever - I dont know.. but for INS correction it can take signals from GPS or GLONASS.. whether it is GPS and/or GLONASS - I am not sure.. so wheter it carried both recivers or one - if one, which one.. I dont know..

But it can take signals from both.. and from GAGAN/IRNSS when they become operational..

Austin wrote: Well a MMW seeker is small enough to fit into the nose of anti-tank missile , thats the USP of MMW seeker , small , high resolution ,high discrimination, all weather capability , making it ideal for Fire and Forget type and terminal homing scenario , even signature matching based on known RF signature of target is possible.

I guess it has to do with range that mmw seeker can give.. like you mentioned if mmw seeker can give a 10km range - is that enough when the missile is moving so fast and the target is also moving (if that is what we want)... I guess that is the only consideration.. bcoz when the missile comes to the pre-determined point where it scans for the target -- the target has to be there.. so for that may require a longer range seeker..

for higher range requirements - does the mmw become over-sized?

Austin wrote: I dont think one needs any complicated S shape manouver to attack a land target , because flying low at 10 m is itself a challenging target to detect at those speed , even a Top Attack while terminal hom
[/quote]

I think the complicated S-manouver for land target is only in cases where the "soft portion" or "high value portion" of the target is on the other side to the general direction of the missile's direct flight path.. if that is desired..
During one of Army's tests from Chandipur when it was fired at a ship -- it just went around the hull and hit it from otherside.. instead of the hullside that is directly ahead... Now what type of targets are there for which army wants to use this ?
Last edited by rakall on 05 Mar 2009 19:13, edited 1 time in total.
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Re: Indian Missile Technology Discussion

Post by k prasad »

Austin wrote:
rakall wrote: Brahmos uses GPS/Glonass for INS correction.. But the first test failure had nothing to do with GPS.. The test was conducted at a 50km range - INS (which is is pretty accurate) at the 50km range would be very accurate... the error "if any" would be too small to require significant GPS correction..

The failure was with the new algorithm which had to find a target among a cluster of targets with similar RCS..

Have your pick of what to believe..
Rakall , I believe in what those guys say.

1 ) Brahmos might be using GPS/GLONASS to get an initial fix of launcher position , this is for conditions where the launcher is always on the move ( could equally be ships and submarines ) , once the initial fix is obtained , for the rest of its flight it depends on INS based navigation with no GPS inflight updates , more ever the time of flight for the full range is so short that the INS error if at all if negligible , and the MMW radar can guide the missile to its target.

2 ) The failure of the algo is an acceptable answer , what is not acceptable is no new seeker , for all practical purpose it will be a MMW seeker which can discriminate a small insignificant target among a cluster of targets.

A MMW seeker though is limited on range i.e. ~ 5 to 10 km , but typical MMW seekers FMCW type with a bandwidth of 500 MHz and a range resolution of 30 cm , high range resolution is possible with MMW seeker , which will help in detection of small stationary or ground slow moving targets or even target based on known RF signatures , all in all perfect for what DRDO claims for Brahmos Block II
Austin, your conjecture is different from what the BrahMos guy told me and Shiv.... that is, the missile flies, and the SCAN algorithm correlates the radar image with the required target to identify it... then, the GPS/GLONASS signal is simultaneously used to locate the missile, by correcting the INS (which needs to be highly accurate for this role), and at the correct time, INS gives the signal to the missile for it to tip - this makes the FCS turn the missile so that it can attack the target right from the top to be accurate and powerful.

It was quite clear that GPS signal is used, and given that Block II is an LACM variant, the talk about ships etc is irrelevant. Additionally, given that the missile can pick up the ship very easily without the need for GPS or anything, GPS is not needed.

mmW may be our collective wet dreams, but lets leave the vaporware out of this discussion till we get a clear info from DRDO and BrahMos ppl - till now, mmW is not talked about.

This is my last post on the topic.

@Rakall, the BrahMos guy told me that the last test had only GPS signal... today's test had both GPS and GLONASS receivers.
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Re: Indian Missile Technology Discussion

Post by rakall »

k prasad wrote:
@Rakall, the BrahMos guy told me that the last test had only GPS signal... today's test had both GPS and GLONASS receivers.
Does that mean there was a GPS failure in the last test?

because the way you have written the sentence, it is easy to conclude "last test failed bcoz of GPS failure.. todays test suceeded bcoz it had both".

PS: BTW - posted Gripen brochures & book in AeroIndia thread.. will post the rest of SAAB stuff later.. out of Blr for next 4days - going to my native to get little Tejas to Bangalore..
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Re: Indian Missile Technology Discussion

Post by k prasad »

rakall wrote:
k prasad wrote: @Rakall, the BrahMos guy told me that the last test had only GPS signal... today's test had both GPS and GLONASS receivers.
Does that mean there was a GPS failure in the last test?

because the way you have written the sentence, it is easy to conclude "last test failed bcoz of GPS failure.. todays test suceeded bcoz it had both".
Yes rakall... that is what was the issue... the GPS signal was not received at the crucial last second, and INS held the data, which meant that the missile didn't tip - it ended up going a few meters over the target and hit the sands about 5-10 km behind (IIRC).

BrahMos aren't sure if the GPS deliberately blinked, or there was some genuine error... either way, it pointed out that a single source would not be reliable. I think GPS will be the first line, with GLONASS after that.
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Re: Indian Missile Technology Discussion

Post by rakall »

k prasad wrote:
rakall wrote: Does that mean there was a GPS failure in the last test?

because the way you have written the sentence, it is easy to conclude "last test failed bcoz of GPS failure.. todays test suceeded bcoz it had both".
Yes rakall... that is what was the issue... the GPS signal was not received at the crucial last second, and INS held the data, which meant that the missile didn't tip - it ended up going a few meters over the target and hit the sands about 5-10 km behind (IIRC).

BrahMos aren't sure if the GPS deliberately blinked, or there was some genuine error... either way, it pointed out that a single source would not be reliable. I think GPS will be the first line, with GLONASS after that.
I think I shud shut-up about the GPS bit now..
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Re: Indian Missile Technology Discussion

Post by vavinash »

Does it make sense to use brahmos as awacs killer when far lighter KS-172 (750 kg)or R-37 is available? Even KS-172 will depend on the signals from Awacs or MKI to guide it to the vicinity. Its only at 50 km the missiles seeker goes active.
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Re: Indian Missile Technology Discussion

Post by rakall »

vavinash wrote:Does it make sense to use brahmos as awacs killer when far lighter KS-172 (750 kg)or R-37 is available? Even KS-172 will depend on the signals from Awacs or MKI to guide it to the vicinity. Its only at 50 km the missiles seeker goes active.
the only point is -- after the initial whispers about "cooperation on KS172", everything seems to have gone cold.. As of now KS172 was not even seen on Ru platforms..

the way things have gone with Gorshky, MRTA, PAK-FA -- the friendship seems to have soured..
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Re: Indian Missile Technology Discussion

Post by vavinash »

Even then a 2.5 tonne awacs killer is simply too heavy. Wouldn't it be simpler to use the AAD (lighter) for LRAAM than brahmos.
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Re: Indian Missile Technology Discussion

Post by SaiK »

is it good to have an electro-optical homing for LACM for terminal phase, thus removing the dependency with satellite based corrections that could be used for mid-course INS adjustments onlee?
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Re: Indian Missile Technology Discussion

Post by Avinash R »

India to test Interceptor Missile on Friday
Thursday, March 05, 2009 18:37 [IST]

New Delhi: India will Friday test launch its indigenous interceptor missile that will destroy an incoming ballistic "enemy" missile at an altitude of 80 km and will provide defence against Pakistani and Chinese missiles, an official said.

"All the preparations have been made and all the scientists are working to make the test successful," a Defence Research and Development Organisation (DRDO) official said. The test, to be conducted at Wheeler s Island off the coast of Orissa, will establish the credible missile defence against Paksitan s Hatf and Ghauri missiles. The first test of the interceptor missile was conducted in 2006.

"During the test an enemy missile which will be a modified version of the Dhanush surface-to-surface missile will will be fired from a naval ship in the Bay of Bengal and simulate the terminal phase of the flight of a ballistic missile with a range of 1,500 km, similar to Pakistan s Ghauri missile," the official said. "As the incoming missile nears Wheeler Island, a Prithvi air defence missile will be launched to intercept it at an altitude of about 80 km and kill it," the official added.

DRDO needs to carry out at least three to four trials with both versions before the missile shield is certified for operational use. "The test will mark the completion of the first phase of the programme and it will secure operational clearance by 2012-13," the official added. On Dec 6,2007,DRDO had for the second time successfully tested an endo-atmospheric - below 30 km altitude - version of the ballistic missile defence shield.

The missile aims to protect populated areas and vital installations like nuclear power stations and oil wells. The missile shield will have highly sensitive radars to track incoming missiles. The guidance system would ensure that the interceptor collides with the incoming missile within a matter of seconds, thereby saving vital targets from destruction. Baptised as the Prithvi Air Defence system, the agile interceptor has now been renamed Pradyumna.

DRDO says its missile system is comparable to the Israeli Arrow system and the American Patriot system, both of whose manufacturers are courting the Indian defence establishment for possible orders. DRDO expects ballistic missile shield to take care of threats from existing Chinese and Pakistani missiles. While Pakistan possesses missiles with ranges between 400 and 2,000 km, the Chinese arsenal varies from a range of 300 km to 2,800 km.
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Re: Indian Missile Technology Discussion

Post by ramana »

I wish the reporters of the recent test had described what was the test about and what objectives were achieved. its very distracting not to mention unprofessional to keep jumping between the recent test and the old test. Sure they have to mention the old test but can they do that once they have reported on the current test? And the IA attitude of making backgorund comments is also condemnable. If you have something to say, say it openly and not hint vaguely.
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Re: Indian Missile Technology Discussion

Post by Arun_S »

SKrishna wrote:Arun Saar

I am still waiting for your promised article on Shaurya (or have I missed it?)
You have not missed, it is I who has not delivered. Did not get time to HTML'ise it to put on BR. There are not enough hours in day due to work. Bearly get enough time to browse some BRF pages, and no quality time to translate the article into html.

I am trying to learn BR's new CMS feature (thanks to Naresh) that is supposed to reduce the workload in putting up articles. I need some learning there.
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Re: Indian Missile Technology Discussion

Post by Arun_S »

Singha wrote:we dont get the 1m accuracy mil grade signal on encrypted channel, just the civilian channel. so it can be depended on only to get into general area not for taking out precision targets.
unkil can also degrade the signal or shut down the sats in the periods of time they are in our range at will in a time of war to help the munna.
I wouldnt trust Rus too much either....

better to put out a little constellation of our own to cover asia.
Singha saab, think of other ways. There is this thing called GAGAN that does something relevant here in terms of surveyed coordinates of launch site and target datum for BrahMos INS to do its magic. :wink:
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Re: Indian Missile Technology Discussion

Post by Arun_S »

Nitesh wrote:
kobe wrote: - Mushi butt recognition will be used (if available)
:rotfl: :rotfl: :rotfl: :rotfl:

which algorithm does this?
Nose of goat loving Maqbool Butt from Azad Swat. 8)
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Re: Indian Missile Technology Discussion

Post by Arun_S »

Austin: Pls wait till the fat lady sings and news of actual seeker hardware comes out. It could be a mmW hardware breakthrough or could as well be a algorithm breakthrough. Both ways India wins.
k prasad wrote:Yes rakall... that is what was the issue... the GPS signal was not received at the crucial last second, and INS held the data, which meant that the missile didn't tip - it ended up going a few meters over the target and hit the sands about 5-10 km behind (IIRC).
To me that does not make sense. No missile designer will wait for last few second (from the time missile needs to tip) to re-align its INS from GPS; one might as well throw the INS junk and instead get the INS used in first generation DARIN.

Pls note that the value of GPS is only in helping INS get to vicinity of target so that SCAN correlator algorithm can do its job and reduce CEP due to INS from 30 meter to 1 meters due to SCAN correlator algorithm . Flight Control System's targeting decision to tip missile trajectory is largely based on SCAN correlator algorithm input and not INS. The root cause IMHO of previous test failure was SCAN correlator algorithm not locking to the target because either:
  • A. it was not able to initialize its frame from what INS told it
    B. or the SCAN correlator failed to resolve/acquire target due to some bug.
Scant press reports indicate it was A. was the cause ; viz initializaion code of SCAN correlator algorithm .

IMO this test succeeded not because GPS signal was being received, bit because they bug fixed the initialization code of SCAN correlator algorithm that should have worked, even if INS did not receive any mid course datum update from GPS for such a short duration flight.
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Re: Indian Missile Technology Discussion

Post by vsudhir »

Missile defence shield: India to test interceptor on Friday
"During the test an 'enemy' missile which will be a modified version of the Dhanush surface-to-surface missile will be fired from a naval ship in the Bay of Bengal and simulate the terminal phase of the flight of a ballistic missile with a range of 1,500 km, similar to Pakistan's Ghauri missile," the official said.

"As the incoming missile nears Wheeler Island, a Prithvi air defence missile will be launched to intercept it at an altitude of about 80 km and kill it," the official added.

DRDO needs to carry out at least three to four trials with both versions before the missile shield is certified for operational use.

"The test will mark the completion of the first phase of the programme and it will secure operational clearance by 2012-13," the official added.
Baptised as the Prithvi Air Defence system, the agile interceptor has now been renamed Pradyumna.
SaiK
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Re: Indian Missile Technology Discussion

Post by SaiK »

Pradyumna! :roll:
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Re: Indian Missile Technology Discussion

Post by shyamd »

Are the tests usually undertaken in the morning IST?
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Re: Indian Missile Technology Discussion

Post by ManuJ »

Arun_S wrote:
k prasad wrote:..GPS signal was not received at the crucial last second...
...The root cause IMHO of previous test failure was SCAN correlator algorithm not locking to the target because either:
  • A. it was not able to initialize its frame from what INS told it
Both versions can be correct...the bug must have been in the SCAN algorithm, which waited for GPS signal before initializing its frame (in other words, GPS signal was pre-requisite for it to initialize). So in a way, not receiving GPS signal caused the failure.

But it was ultimately a failure of SCAN. By fixing SCAN so that it is no longer dependent on GPS for initializing, it is much more robust. Having RLG INS would make it even better.
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Re: Indian Missile Technology Discussion

Post by Arun_S »

ManuJ wrote:Both versions can be correct...the bug must have been in the SCAN algorithm, which waited for GPS signal before initializing its frame (in other words, GPS signal was pre-requisite for it to initialize). So in a way, not receiving GPS signal caused the failure.
Pls read my post again. Aiming algorithms works with IMU/INS, there will be no connection between SCAN algorithm and GPS.

What you hypothesize "GPS signal was pre-requisite for it to initialize"
serious missile developer don't do such unwanted and constraining sequencing of unconnected entities.

We onlee argumentative Yinjuns :wink:
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Re: Indian Missile Technology Discussion

Post by Arun_S »

SaiK wrote:Pradyumna! :roll:
How about Monica Lewinsky! :wink:
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Re: Indian Missile Technology Discussion

Post by abrahavt »

Singha saab, think of other ways. There is this thing called GAGAN that does something relevant here in terms of surveyed coordinates of launch site and target datum for BrahMos INS to do its magic.
GAGAN is GPS augmented signal. So if there is no GPS signal there is no GAGAN.
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Re: Indian Missile Technology Discussion

Post by andy B »

kobe wrote:1) i had a yumble reguest only, heed - no heed, anyone can decide.
2) no one is implying that we should only post links to news articles
3) all the above overly simplistic calculations are FALSE, i know, but i can't tell you why
4) i can only request to focus on intent of the forum and you guys do / write whatever you want
5) yes, no one is a born guru and one way to become guru is to be humble, be quiet, and read a lot, memorize a lot, and if necessary ask questions, then contemplate, meditate, and then again read a lot, memorize a lot, all the while being humble and quiet.
Kobe mate my reply to your post before was more on the lines of being reactive/negative and I apologise for that.
Its hard to learn about missile technology when studying and working in finance...
Yes I fully agree with you on the above mentioned points and your yumble request no doubt.
However given that you obviously know a lot more about this it would have been better if you could have shown me some direction (Ofcourse you will have your own reasons for not telling but hints are always appreciated) as my only intent was to learn....JMT
Either way I will take the advise on board and in the future and implement it accordingly.
No hard feelings...Cheers
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Re: Indian Missile Technology Discussion

Post by Gerard »

SaiK wrote:Pradyumna! :roll:
Are they still consulting Vajpayee regarding names?
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Re: Indian Missile Technology Discussion

Post by Bharat »

Pradyumna is another name for Lord Krishna and in some writings is the son of Lord Krishna and Rukmini. He is also one of the few who knew how to break the Chakravyuha.

http://en.wikipedia.org/wiki/Pradyumna
http://en.wikipedia.org/wiki/Wars_of_Hindu_Mythology

I don't get the signifigance of it, but is it all in a name ?
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Re: Indian Missile Technology Discussion

Post by Gerard »

Some of us have still not gotten over "Tejas"
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Re: Indian Missile Technology Discussion

Post by Atri »

Bharat wrote:Pradyumna is another name for Lord Krishna and in some writings is the son of Lord Krishna and Rukmini. He is also one of the few who knew how to break the Chakravyuha.

http://en.wikipedia.org/wiki/Pradyumna
http://en.wikipedia.org/wiki/Wars_of_Hindu_Mythology

I don't get the signifigance of it, but is it all in a name ?
Perhaps, his ability to break Chakravyuha prompted the nomenclature. :P

But, honestly, there are scores of relevant names available even in Sanskrit...
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Re: Indian Missile Technology Discussion

Post by NRao »

"Pradyumna" also ......... mean "Hero".
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Re: Indian Missile Technology Discussion

Post by SaiK »

ok.. good enough now.
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Re: Indian Missile Technology Discussion

Post by Anujan »

NRao wrote:"Pradyumna" also ......... mean "Hero".
I think somebody made an observation Project Air Defence (Prad) and probably grew up near yamuna. There you go.
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Re: Indian Missile Technology Discussion

Post by rakall »

Arun_S wrote:
SaiK wrote:Pradyumna! :roll:
How about Monica Lewinsky! :wink:

The enemy missile would get a pretty hard blow... job.. then. :wink:
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Re: Indian Missile Technology Discussion

Post by m mittal »

I guess Pradyumna and Ashwin are the names which have been flying around after the 1st endo-atmospheric test.

IMHO they are good names.......I somehow do not like Tejas.......they could have come up with some thing like "udan khatola" :rotfl:

Tejas IMO is a pretty lame name...........they should rename it to something else
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