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Subject: Sampson or AN/SPY1
usajoe1    5/23/2009 5:10:37 AM
I think the the only real advantage for the AN/SPY1 on the Arleigh Burke DDG is that it has four fixed arays,that give it a continues coverage over the rotating arays of the T-45's Sampson radar. Which system do you guys think its better and which of these destroyers is a better Air Defense ship.
 
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StobieWan       4/9/2010 5:22:53 PM
Not sure I follow - the UK involvement uses SAMPSON and the only bit of that technology that's in common, is the ASTER missile itself - whatever misgivings the Italians have about any radar systems they're making, we're not replicating their work.

What *do* they know that we don't ? References welcomed of course,

Ian
 

Ian
 
Ask yourself this....




WHY did Italy cancel SAMP-T (ASTER) as its land-based missile at two firing units, cap its naval ASTER  order, and throw its lot in with MEADS in 2004?


 

Italy is responsible for the multifunction fire control radar and for part of the IFF system for the project.  They trust the Germans to fix their surveillance radar test bed screw-ups and they've seen PATRIOT in action as well as ASTER.   


 

Hint: they BOTH know something you don't.

 

H.





 

 
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Hamilcar       4/9/2010 5:53:49 PM
Not sure I follow - the UK involvement uses SAMPSON and the only bit of that technology that's in common, is the ASTER missile itself - whatever misgivings the Italians have about any radar systems they're making, we're not replicating their work.

What *do* they know that we don't ? References welcomed of course,

Ian
 

Ian
=========================================================
Ask yourself this....

WHY did Italy cancel SAMP-T (ASTER) as its land-based missile at two firing units, cap its naval ASTER  order, and throw its lot in with MEADS in 2004?

Italy is responsible for the multifunction fire control radar and for part of the IFF system for the project.  They trust the Germans to fix their surveillance radar test bed screw-ups and they've seen PATRIOT in action as well as ASTER.   

Hint: they BOTH know something you don't.

H.
==============================================
 
France, Italy and  Britain all use variants of SMART-L
 
 
Its the missile.
 
H..
 
 

 
 
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StobieWan       4/13/2010 9:03:10 AM
Mm...we use SAMPSON MFR for the AA search/track portion but carry the SMART-L related S8150 set for 3D search radar - so I'd stick with my assessment that our radar system is different from the Horizon frigates. I'd concede (with some relief at this stage) that it does look to be issues with the missile however.

So, the only thing we brought forward from the Horizon project, don't work. Pants.

Ian

 

France, Italy and  Britain all use variants of SMART-L


 
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southwalls       6/30/2010 5:14:17 PM
The Aster 30s problems have now been proven fixed. Firings with the Sampson radar in the south of France, using the new build of Aster have had two successful intercepts against the target trajectories which were previously causing problems. The issue was traced to a  flaw in the design of the missile "strakes" which has been corrected.
 
 
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StobieWan       7/1/2010 12:35:30 PM
Sadly when you read the announcement through, it looks like they've conducted four firings - one from each of the Italian and French vessels I'm guessing and two from the Longbow.

Given that only one of the firings was the salvo launch at a sea skimmer with a fast 90 deg jink programmed in, I'm unconvinced that the tests demonstrate any statistical certainty. Fire another dozen off and I'll relax.

Ian

 
The Aster 30s problems have now been proven fixed. Firings with the Sampson radar in the south of France, using the new build of Aster have had two successful intercepts against the target trajectories which were previously causing problems. The issue was traced to a  flaw in the design of the missile "strakes" which has been corrected.


 


 
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southwalls       7/2/2010 7:49:28 PM
Actually, as far as Sampson goes, it's more like:
Test A - 2  missiles against low target, both fail
Test B -  repeat of Test A, again both missiles fail
 
Extensive tests and simulation reveal problem with a recent design mod to strakes, redesigned strakes are predicted to fail under the high G manoeuvre which occurs against the threat trajectory used in Tests A and B
 
(Only) Tweak to Missile is to replace strakes with stronger ones
 
Test C - repeat of Test a with fixed missiles, both missiles intercept target
 
So, although nothing is ever certain, we have 4 failures 1 analysis which predicts a mod which will stop failure, mod is done and 2 successes follow, which makes it quite likely that the mod fixed the issue. 
 
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southwalls       7/2/2010 7:53:48 PM
Putting it another way. If you went on 4 bike rides and got a puncture each time, then you looked into things and found a suspect spoke sticking through your rim, which you fixed, then had 2 bike rides of similar length with no punctures.. would you think you had fixed the issue, or would you think you had been lucky?
 
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Hamilcar    No it didn't.    7/2/2010 8:02:06 PM

Actually, as far as Sampson goes, it's more like:

Test A - 2  missiles against low target, both fail

Test B -  repeat of Test A, again both missiles fail


 

Extensive tests and simulation reveal problem with a recent design mod to strakes, redesigned strakes are predicted to fail under the high G manoeuvre which occurs against the threat trajectory used in Tests A and B

 

(Only) Tweak to Missile is to replace strakes with stronger ones

 

Test C - repeat of Test a with fixed missiles, both missiles intercept target

 

So, although nothing is ever certain, we have 4 failures 1 analysis which predicts a mod which will stop failure, mod is done and 2 successes follow, which makes it quite likely that the mod fixed the issue. 


H.
 
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StobieWan       7/2/2010 8:05:28 PM
Very much depends on if the original test failures were due to a production or design issue. A production issue makes more sense as the first 30 odd Aster tests have been tolerably successful. 

With respect to the latest round, only the HMS Longbow salvo firing is significant (the other two tests, one from an Italian and one from a French vessel were low stress firings and didn't replicate the fail scenario - from my perspective, they were regression testing - they showed only that the production rework hadn't broken anything new)

It's hard to get a feel for it but the sense of it is that the original RN test fails were the first time the missile had been tested to that extent. Both failed. We've got one new test which is a pass.   

I'd like salvo firings against supersonic targets please.


Ian

 
 
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StobieWan       7/2/2010 8:14:13 PM
Back to the original topic - SPY-1D scans on a rotating basis, so it's certainly not all four faces providing data. Can't swear to how it does work but figures I've seen from one of Friedman's various publications indicates it's scanning at 5rpm roughly. Effectively, on an AB with one transmitter, the situational picture is built up in passes, face by face. Powerful and very advanced for the time, but it is acknowledged to struggle with terrain clutter or near-water chop.

Sampson transmits simultaneously on both faces of it's array so at anyone time it's scanning 240 degrees of sky. 

If someone can give me an unclass overview of how SPY works, I'll make my mind up :)

Ian

 
I think the the only real advantage for the AN/SPY1 on the Arleigh Burke DDG is that it has four fixed arays,that give it a continues coverage over the rotating arays of the T-45's Sampson radar. Which system do you guys think its better and which of these destroyers is a better Air Defense ship.

 
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