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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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Hamilcar    Do not rely on Friedman.   7/2/2010 9:33:33 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.




Its not the radar, its the COMPUTER generated refresh rates and he gets it wrong. And that is not the same thing today as when in first service.

H.
 
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USN-MID       7/2/2010 9:36:29 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.

First, I served on DDGs. I have no idea why Friedman would say it alternates which face is active at any given time. That's just wrong.
 
Second, AEGIS/SPY has continuously been upgraded. The system is still the most powerful to put to sea, and the constant upgrades have corrected previous limitations (particularly the system software), including dealing with land masses and environmentals.  When the system was originally programmed, they only considered Soviet bombers and ASMs. Today, it also effectively functions as a surface search radar, though it is a bit of a waste of resources for it to do so.
 
Third, any radar will struggle with environmentals. The SPY-1D(V) was specifically designed to overcome the limitations previous variants had in the littorals. 




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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southwalls       7/5/2010 4:04:03 AM
The rate at which a target can be illuminated is not necessarily the overriding concern.
 
Say, for instance, a target is being tracked that can manoeuvre at 10g, this means in 1 second it can change its position by about 50m from where it would be if it didn't accelerate (0.5at^2).
 
If the target is at 10km range, then 50m laterally will change the target angle from the radar by about 0.3 degrees, the radar will not know whether a measurement at that 1s point probably indicates a sudden manoeuvre unless its angular measurement accuracy is at least twice that, i.e it has an angular measurement accuracy of 0.15 degrees.
 
The same kind of logic applies in the range direction, where the range measurement accuracy of the radar has to be about 25m in order to decide whether 50m deviation from a straight line probably indicates a manoeuvre.
 
What we end up with is a maximum rate that it is worth looking at for a given target, with decreasing gains when the radar visits the target faster than that. This ideal rate depends on the measurement accuracy of the radar.
 

 
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mabie       10/6/2010 7:29:37 AM

http://www.mod.uk/DefenceInternet/DefenceNews/EquipmentAndLogistics/RoyalNavyFiresSeaViperFromType45Destroyer.htm

Royal Navy fires Sea Viper from Type 45 destroyer
An Equipment and Logistics news article

4 Oct 10

Sea Viper, the Royal Navy's groundbreaking new air defence missile system, was fired from a Type 45 destroyer for the first time last week.
 
An Aster 30 missile is fired from HMS Dauntless 
[Picture: MBDA 2010]

The system successfully fired an Aster 30 missile from HMS Dauntless at the MOD range in the Hebrides and hit a moving target drone.

.......................................

Antoine Bouvier, Chief Executive Officer, said: &S220;These successful firing trials demonstrate that MBDA has fully mastered the technical issue with the Aster strake that was uncovered last year on recent missile manufacturing. The trials have been completed in support of making sure our domestic customers are in position to deploy the full operational capability of the PAAMS(E) system with the French and Italian navies and the Sea Viper system with the Royal Navy later this year. "

 
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justsomeaussie       10/27/2010 9:06:04 PM

The rate at which a target can be illuminated is not necessarily the overriding concern.

 

Say, for instance, a target is being tracked that can manoeuvre at 10g, this means in 1 second it can change its position by about 50m from where it would be if it didn't accelerate (0.5at^2).

 

If the target is at 10km range, then 50m laterally will change the target angle from the radar by about 0.3 degrees, the radar will not know whether a measurement at that 1s point probably indicates a sudden manoeuvre unless its angular measurement accuracy is at least twice that, i.e it has an angular measurement accuracy of 0.15 degrees.


 

The same kind of logic applies in the range direction, where the range measurement accuracy of the radar has to be about 25m in order to decide whether 50m deviation from a straight line probably indicates a manoeuvre.


 

What we end up with is a maximum rate that it is worth looking at for a given target, with decreasing gains when the radar visits the target faster than that. This ideal rate depends on the measurement accuracy of the radar.


 
I think this solves the problem:
 
"New radar allows 'channels of fire'"
 
In this arrangement effectively providing 6 radar AESA faces each independantly scaning a 60 degree arc provding a very high updade rate and 4 phased array illuminators each covering 90 degree arcs providing the terminal guidance.

If you have a bigger platform you just make the array bigger.

 
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