Newsgroups: sci.military.naval
From: norton@ASYNC01.acm.org (Scott Norton)
Subject: Re: Harpoon (from Re: Arsenal vs BB)
Date: Sat, 15 Feb 97 21:42:07 EST

In article <8WAdGDA++i+yEwmB@aetherem.demon.co.uk> Matt Clonfero <Matt@aetherem.demon.co.uk> writes:
> Ron Cocuzzi <cocuzzir@vitro.com> wrote:
> 
> >> Harpoon had a terminal pop-up since it was initially designed to kill
> >> surfaced SSG / SSGNs. Exocet doesn't have a terminal pop-up (see the
> >> pictures of HMS Sheffield - the hole is low on the side of the ship).
> >> Modern versions of Harpoon don't pop-up anymore.
> >> 
> >Not true.  The D model has a selectable terminal maneuver which is
> >programmed by the SWG operator.
> 
> Fair point. Now, is anyone going to use a pop-up in the face of
> real antimissile defences (erm, CADS-N-1) - with a subsonic
> missile it just gives the defences a longer window to kill
> your shot in.

The "best thing" for a missile to do to increase its chance of a hit
is not at all clear.  If you don't maneuver, you're easy to hit.
Maneuvers in the horizontal plane are easier to detect than vertical,
because multipath makes elevation accuracy less than azimuth.  But if
you maneuver vertically, you come out of the multipath environment.

Plus, maneuvers expose more of the missile, increasing the
cross-section for CIWS rounds from about 0.3 m^2 to a square meter or
two.  They also expose the less-hardedened sides of the warhead to
hits, and keep the warhead from "hiding" behind the forebody.  They
also may increase the missile's radar cross section.

If you take a hit in the radar or autopilot while jinking, you don't
have the chance to ballistically impact the target the way you would
if you were flying straight at it.

So, is the ship you are attacking defended by missiles, guns, or what?
Are the guns prox fuzed, or hit-to-kill?  Are the radars X-band, Ku,
Ka, or W band?  What is the sea state? (Multipath is much worse in
smooth seas.)  Does the CIWS have an adjunct IR tracker, and if so,
what is your missile's IR signature?  What warhead do you have, SAP,
shaped charge, or frag, and where do you want to put it.

Anti-ship missile designs are influenced by a lot of details of the
target, launching platform, projected employment environment, and
desired effect.  You can't just say, "pop-up is dumb."

-- 
Scott Norton
Norton@ACM.org
Defense Technology, Inc.
2920 South Glebe Road
Arlington VA  22206
+1-703-299-1656, fax: +1-703-706-0476