Talk:Goalkeeper CIWS

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[edit] Reaction time

"The system's reaction time to a Mach 2 sea-skimming missile from automatic detection to kill is reported to be 5.5 seconds with the engagement starting at a range of 1500 m and ending with a kill at 300 m."

At Mach 2, the missile is doing a mile in less than, what, 3 seconds? The total engagement range defined above is 1200 meters. Since a mile is ~1600 meters...

5.5 seconds requires the engagement to start much farther away, not including travel time of the CIWS rounds to target. (Mach 2 inbound for 5.5seconds at sea level travels ~4km.)

Either the quoted statement above is intended to express the irony of Goalkeeper's inability to initiate, engage, and terminate the target before detonation, or someone's making up numbers.—The preceding unsigned comment was added by 207.213.217.230 (talk • contribs) July 11, 2006 (UTC)

Actually, you may be misunderstanding the sentence. "Engagement starting at a range of 1500 m" means Goalkeeper starts firing bullets at the target at 1500 m. Prior to this it would have detected the target with the search antenna. Then tracked it with the search antenna, determined it to be a threat, then slewed the mount to position the tracking antenna and track the target with the track antenna. The engaging the target with bullets if required beginning at maximum range. According to this article the search antenna has a range of 30 km, if it takes 5.5 seconds to go from detect to kill all it has to do is detect the target outside of 4 or 5 km to engage (start firing) at 1.5 km. Dual Freq 23:30, 6 September 2006 (UTC)

[edit] Citation needed

Phalanx has a search antenna and track antenna just like Goalkeeper. The search antenna also tracks targets and Phalanx prioritizes those targets and slews the mount to use the tracking antenna to track and engage the target if required. Sounds very similar to what is described here for Goalkeeper, how is goalkeeper different in this respect? I don't know the number but Phalanx tracks things with the search antenna and will use the track antenna for more accurate data needed to engage the target. Dual Freq 22:53, 6 September 2006 (UTC)

Appareantly the Phalanx tracks 2 targets, while the Goalkeeper tracks 18 targets.—The preceding unsigned comment was added by Fvdham (talk • contribs) 13:19, December 30, 2006 (UTC)

Still looking for a citation. [1] says goalkeeper can track 30 targets. [2] says Phalanx prioritizes its first 6 targets. The only difference I can see is that Phalanx's search antenna moves with the entire mount and might prevent searching when the mount is pointed at extreme angles. The search antenna tracks targets and Phalanx prioritizes those targets and slews the mount to use the tracking antenna to track and engage the target if required. I don't know where the 2 target number is coming from, but as far as Phalanx number of tracks, I don't think anyone will find an unclassified number to cite. If it only tracked 1 target it wouldn't need to prioritize 1 target. It can track numerous targets with the search antenna, just like any other 2D air search radar tracks targets. Just like the 2D primary radar tracks targets at your local airport. We need a citation for the 18 number and the 1 number, otherwise I'd say it can be removed and replaced with something like: Phalanx's search antenna moves with the entire mount while Goalkeeper's is fixed providing enhanced target detection while an engagement is in progress. --Dual Freq 14:18, 30 December 2006 (UTC)

My understanding of the above (sorry cant find sources but think this was covered by an issue of Janes) is that Phalanx has only one radar transmitter/receiver while the Goalkeeper has two. In the case of the Phalanx it is coupled to either the search radar or the tracking radar but not both. By having only one rather than two it reduces the size and cost of the system. What happens is that the Phalanx first runs with the transmitter switched to the search subsystem. It builds up a threat picture and prioritizes targets. When an engagement is commanded the transmitter/receiver is switch to the tracking subsystem and engages the target. When the engagement is complete the transmitter/receiver is switched back to the search subsystem and the system must rebuild the picture to decide which target should be engaged next. This ofcourse takes time, to much time for some people. The Goalkeeper has both a search and a tracking radar. Both are on all the time so that while the system is engaging a target the search radar is keeping the air picture up to date and the system is deciding which target it will engage next. Hence there is no delay between switching to the next target.

--Rbaal 01:52, 21 January 2007 (UTC)

Well that certainly makes sense, based on your statement and another google search I agree with that assessment about the limitations of a single TX/RX system.[3] The statement in the article: "Phalanx can only track and engage one target at a time, while Goalkeeper can track 18 targets and switch to engage the greatest threat." still seems misleading. --Dual Freq 02:11, 21 January 2007 (UTC)