bxr307@csc.anu.oz (06/28/90)
From: bxr307@csc.anu.oz Organization: Computer Services, Australian National University News-Moderator: Approval required for posting to sci.military Lines: 34 In article <1990Jun26.025008.15408@cbnews.att.com>, tek@CS.UCLA.EDU (Ted Kim (Random Dude)) writes: > > > From: tek@CS.UCLA.EDU (Ted Kim (Random Dude)) > > In article <1990Jun22.043119.27816@cbnews.att.com> malloy@nprdc.navy.mil (Sean Malloy) writes: >>Against a dozen missiles, even the twin-rail launchers can keep up -- >>the rate of fire is two missiles about every 30 seconds, so with both >>launchers starting loaded, a Ticonderoga could fire twelve missiles in >>1 minute -- quick enough to engage twelve missiles incoming >>simultaneously at Mach 3, given normal radar horizons. > > The book USNI World_Naval_Weapon_Systems claims the Mk 26 launcher > (the twin arm launcher on early Aegis ships) can launch a pair of > missiles once every 10 seconds. In the same book, the ROF of the Mk 41 > VLS is pegged at 1 missile per second. Surely a better determinant of rate of fire of a missile launcher using a semi-active guidance system that the Standard missile does is the number of missiles that can be guided at the same time towards a target? It might be fine for you launcher to be able to fire missiles off wily-nily, however how much good is that when only the first two or three are actually able to be guided to their targets? Added to that must be the problem of at what ranges the engagements begin, because the longer the missile is in flight, the longer it has to be guided and that cuts down the number of missiles that can be launched in a single engagement. I don't know how good the radars on the Aegis system are (and after the Iranian A300 episode I wonder even more) but I would doubt if more than two or four missiles could have handled in one engagement at any one time. Brian Ross
tek@CS.UCLA.EDU (Ted Kim (Random Dude)) (06/29/90)
From: tek@CS.UCLA.EDU (Ted Kim (Random Dude)) In article <1990Jun28.025720.18921@cbnews.att.com> bxr307@csc.anu.oz writes: > ... >Surely a better determinant of rate of fire of a missile launcher >using a semi-active guidance system that the Standard missile does is >the number of missiles that can be guided at the same time towards a >target? Normally that would be so, except the SM2MR (and the ER) are not purely Semi-Active Radar Homing missiles (though they can be fired that way). The SM2MRs are use a two-phase guidance system. In the initial phase, they use inertial guidance with midcourse correction updates. Only in the final few seconds, are the missiles using SARH. The midcourse corrections are encoded in the tracking radar signal from the SPY-1. >It might be fine for you launcher to be able to fire missiles off >wily-nily, however how much good is that when only the first two or >three are actually able to be guided to their targets? Added to that >must be the problem of at what ranges the engagements begin, because >the longer the missile is in flight, the longer it has to be guided >and that cuts down the number of missiles that can be launched in a >single engagement. The Aegis cruisers carry four Mk99 weapon directors. So four missiles can be in terminal SARH, while others are in flight. The book "Modern Naval Combat" by Chris & David Miller claims the number of missiles in flight not in SARH can be as high as 18. That's probably under very favorable conditions, but I think the point is made. >I don't know how good the radars on the Aegis system are (and after >the Iranian A300 episode I wonder even more) but I would doubt if >more than two or four missiles could have handled in one engagement >at any one time. At the risk of moderator editing, I don't think the SPY-1 radar was proven to be faulty in the Iranian Airbus tragedy. IMHO, it was more that the ship was placed in a situation it was not designed for, the and that the IFF procedures were inadequate. -ted Ted Kim UCLA Computer Science Department Internet: tek@penzance.cs.ucla.edu 3804C Boelter Hall UUCP: ...!{uunet|ucbvax}!cs.ucla.edu!tek Los Angeles, CA 90024 Phone: (213) 206-8696
jeff@aplcomm.jhuapl.edu (JEFF NANIS ) (06/29/90)
From: jeff@aplcomm.jhuapl.edu (JEFF NANIS ) s.att.com> <1990Jun22.043119.27816@cbnews.att.com> <1990jun26.025008.15408@cbnew s.att.com> <1990Jun28.025720.18921@cbnews.att.com> Distribution: usa Organization: JHU/APL, Laurel, MD In article <1990Jun28.025720.18921@cbnews.att.com> bxr307@csc.anu.oz writes: > Surely a better determinant of rate of fire of a missile launcher using >a semi-active guidance system that the Standard missile does is the number of >missiles that can be guided at the same time towards a target? It might be >fine for you launcher to be able to fire missiles off wily-nily, however how >much good is that when only the first two or three are actually able to be >guided to their targets? Added to that must be the problem of at what ranges >the engagements begin, because the longer the missile is in flight, the longer >it has to be guided and that cuts down the number of missiles that can be >launched in a single engagement. You are correct. The illuminator scheduling time is generally the limiting factor in guiding semi-active missiles, especvially with a VLS system. On the other hand, your follow-up comment: > I don't know how good the radars on the Aegis system are >(and after the Iranian A300 episode I wonder even more) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calls for a vehement keyboard-lashing. Everybody, repeat after me: "RADARS DETECT, THEY DON'T IDENTIFY!" (Actually, not completely true, but the SPY-1 is not a synthetic aperture radar or an inverse SAR.) The radar performed perfectly on the Vincennes. It is unscientific rumours like this that journalists and lawyers believe, not the well- educated readership of sci.military. It is the mistaken belief that the radars in some way failed on CG-49 that have made GE (formerly RCA - the builders of the Aegis system) and the place where I work (designers of Aegis) defendants in several misguided (no pun intended) lawsuits placed by fee-hungry, scientifically- ignorant lawsharks for bereaved Iranian families. -- -- Jeff Nanis "If I told you, I'd have to kill you." Not an official opinion which might get me put in jail.
jb7m+@andrew.cmu.edu (Jon C. R. Bennett) (06/29/90)
From: "Jon C. R. Bennett" <jb7m+@andrew.cmu.edu> bxr307@csc.anu.oz writes: > From: bxr307@csc.anu.oz > Organization: Computer Services, Australian National University > News-Moderator: Approval required for posting to sci.military > Lines: 34 . . > I don't know how good the radars on the Aegis system are (and after > the Iranian A300 episode I wonder even more) but I would doubt > if more than two or four missiles could have handled in one engagement at any > one time. > The Aegis system can handle far more then 4 missiles in the air at once, since the missles are launched having been told where their target will be and guide them selves until they reach the vicinity of the target (mid course corrections can be sent to the missle in the event that it's target alters course), and the target is illuminated at the last second by an Aegis crusier (note thats "AN Aegis crusier", since the system is capable of guiding missles launched by other ships). In the event that there are too many targets of the system to handle the system can go into a "panic fire mode" in which it salvos all its missles and the illumination radar is turned on in about a 60 degree beam and the missles take any target. jon
gwh%earthquake.Berkeley.EDU@ucbvax.Berkeley.EDU (George William Herbert) (06/29/90)
From: gwh%earthquake.Berkeley.EDU@ucbvax.Berkeley.EDU (George William Herbert) In article <1990Jun28.025720.18921@cbnews.att.com> bxr307@csc.anu.oz writes: > > Surely a better determinant of rate of fire of a missile launcher using >a semi-active guidance system that the Standard missile does is the number of >missiles that can be guided at the same time towards a target? It might be >fine for you launcher to be able to fire missiles off wily-nily, however how >much good is that when only the first two or three are actually able to be >guided to their targets? Added to that must be the problem of at what ranges >the engagements begin, because the longer the missile is in flight, the longer >it has to be guided and that cuts down the number of missiles that can be >launched in a single engagement. > I don't know how good the radars on the Aegis system are (and after >the Iranian A300 episode I wonder even more) but I would doubt >if more than two or four missiles could have handled in one engagement at any >one time. Some info to clear this misconception up: The Aegis "system" consists of several major components. In addition to an extensive central computer and display system, the main components are: A SPY-1(CG-47) or SPY-1D (DDG-51) Phased Array Radar Four (CG-47) or Three (DDG-51) Mk-62 (?) Target Illumination Radars Two (CG-47) or one (DDG-51) Mk-45 5" gun mounts either Two Mk-26 twin rail missile launchers (early CG-47) One 61-cell Mk 41 VLS missile launcher and one 32 cell (late ^) Two 61-cell Mk 41 VLS (DDG 51) The antiair missile component of the system is the SM-2 Standard missile. The key to the unique effectiveness of the combined system is the synergism of the components. In a many target engagement, the ship will be launching continuously, and the missiles will follow this path: At launch they are given a vector to fly out. They immediately start heading out this track. While they are in this portion of flight, they may recieve new vectors to track out on from the SPY-1 radar system, which is recieving instructions from the central computer to keep missiles headed towards incoming targets. Note that the radar can do this at the same time as it does all other functions. At some point, the ship will point a Mk 62 designator at the target it wants the missile to engage. It then tells the missile that it's been activated, and the missile starts steering towards the illumination signal in a Semi-Active Radar Homing mode. As soon as the missile hits the target, the Mk 62 is pointed to another target. If the first missile misses, the Mk 62 can be held on the same target while another missile is told to track on the signal. Missiles in flight that haven't been designated yet are under the control of the central computer via the SPY-1, keeping the whole anti-missile targeting situation flexible. Hope this helps clear up everyone's understandings of the Aegis system. == George William Herbert == Quantum Mechanics can explain everything == JOAT for Hire: Anything, === except Madonna, Flame Wars, and NASA's space =======Anywhere, My Price.======= Policy. We're working on the first two... == gwh@ocf.berkeley.edu == ___"Gee, I Hope that wasn't a hostage..."___ == ucbvax!lilac!ocf!gwh == The OCF Gang: Making Tomorrow's Mistakes Today
jon@cs.washington.edu (Jon Jacky) (07/02/90)
From: jon@cs.washington.edu (Jon Jacky) There have been several messages in this thread which have reported how the Aegis system is supposed to be able to successfully engage many targets at once. Has this ability ever been demonstrated? That is, has there ever been a test in which a dozen (or however many) drones were flown in from various directions, and the Aegis system succeeded in shooting a lot of them down? What I'm really asking is, what sort of live testing is thought necessary to obtain confidence that performance claims would be achieved in actual combat? - Jon Jacky, University of Washington, Seattle jon@gaffer.rad.washington.edu