Re: warheads (tech related)

["Gary Gore" <ggore@mail.transdata.ca>]

Warning.

There is tech stuff in here, if you don't want to know don't read it.

----------
> From: Bill Garmer <bgarmer@tsc.net>
> To: Mailinglist 'MP' <MP@nostromo.gate.net>
> Subject: Re: warheads
> Date: Monday, April 14, 1997 4:40 PM
> 
> >> Gary - where did you find this?
> >> 
> >> Bill
> >
> >>From a book and the course's I've taken over the years.  I checked my
data
> >before I sent it out over the list.  All that data is published in a few
> >books, so its not secret. :)
> >
> >Why?
> 
> I know it's not secret but it also not correct for guided warheads (ie
most
> US MIRVs and later USSR RVs).  The error for a straight ballistic shot is
> dependent upon the distance the delievery vehicle travelled which is not
> the distance between the launch point and the target but the distance
> through which the vehicle actually travelled.  For example, given the
> equation you site the CEP for a range of zero (you are targetting
yourself)
> the CEP would be zero.  I real life the missile would launch and fly
> straight up being effected by weather, earth rotation, etc and would have
a
> CEP >> 0.  If the missile just blew up in the silo, of course the CEP = 0
> but this is not how missiles are designed.
> 
> It's a side point - I was just curious where it came from.
> 
> Bill

This one is close enough for most people to get the idea that a missile is
not pin point when you are arcing it through the atmosphere, with the
rotation of the earth, the levels of radiation increasing etc..  The
numbers and formula I gave a guidelines, not gospal.

I'll be quoting from a public published source book I have.

"All modern missiles have the large warheads and precision of aim sufficent
to destroy large area targets such as cities, industrial complexes or
airfileds.  Greater precision only becomes necessary when the warhead is
intended to destroy or damage pinpoint, hardend targets, such as ICBM silos
or buried headquarters.  The precision of such a warhead is expressed as
the CEP which is the radius of a circle, centered upon the mean point of
impact, that is the area within 50% of the warheads aimed at the target
will fail.  the size of the CEP is determined by a combination of the
theoretical study and empirical data obtained from the testing programme. 
The CEP is normally understood to apply to the missile's maximum range. 
When fired to less than max. range, the CEP reduces in the same proportion
- so, a 5000 nm missile with a CEP of 0.5 nm, when fired to a range of 2500
nm, will have a CEP of 0.5 x (2500/5000) = .25 nm (470 m).

Of great importance is the distance between the mean point of impact and
the target itself; this is termed the bias, which is the cumulative effect
of all system errors on the trajectory of missile and the RV.  For example,
a critical component in a particular missile system, such as an
accelerometer, might produce an error on operational trajectories such that
the mean impact point was 50ft (15m) beyond the centre of the target. 
other more random events may effect the bias, such as the weather
conditions over the target or uneven wear of the ablative shield during
re-entry.  Clearly, the requirement is for a warhead/ missile system which
is both a small CEP and small bias."

Also we can talk about the single-shot kill probability, but I think that
will begin to bore others on this list.

------------
Gary..
ggore@mail.transdata.ca
http://www.transdata.ca/~ggore/morrow.htm