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a moving target with a projectile that takes a con-
siderable length of time to arrive at its destination.
Accordingly, the gun cannot be aimed at the point
where the target is when detected. It must be
aimed at the point where the target will be when
the projectile gets there; that is, the predicted
position of the target. Furthermore, the path of
the projectile is not a straight line but is curved
by gravity. Wind, variations in atmospheric den-
sity, and other forces also affect the path of the
projectile. In addition, the guns and the fire
control equipment are mounted on a ship that is
rolling, pitching, and moving through water.
The fire control equipment that solves this
problem is usually known as a gun fire control
system. Each battery frequently has more than
one of these systems. The whole battery may be
controlled by one system or may be broken down
into smaller groups, each controlled by a separate
system.
A gun fire control system generally consists
of two parts, one above deck and the other below
deck in a protected position. The above-deck
portion consists principally of a gun director that
acts as the eyes of the battery. It is trained and
elevated so that its optics and radar are always
directed toward the target, thus establishing a line
of sight. Directors vary in size and complexity.
Some are large rotating structures with complex
electrical driving equipment while others are
small, hand-operated devices.
Introduction of radar into the fire control
system has greatly enhanced its flexibility and
accuracy. Radar provides more accurate range as
well as target direction data that is almost as good
as the best optics.
The below-deck components of the system
usually consist of a computer and other related
equipment, although the computer is sometimes
part of the director. The computer receives data
about target coordinates from the director and/or
radar. It uses built-in data about the wind, motion
of the ship, atmosphere, and the projectile path.
It then computes this data into orders needed for
the guns to aim properly to hit the target. These
orders are transmitted directly to the train and
elevation power drives of the gun mounts or
turrets.
Computers make use of complex electrical and
mechanical components to perform continuous
complex calculations. Some are entirely mechani-
cal, with quantities represented by positions of
shafts;
others are electromechanical, with
quantities represented by both positions and
voltages.
All naval ships now use gun fire control
equipment.
SURFACE-LAUNCHED ANTIAIR
WARFARE (AAW) MISSILES
The Navy uses surface-launched missiles both
as offensive and defensive weapons. Surface-
launched missiles are used to destroy surface,
land, and air targets. The following sections
briefly describe some of the Navy’s surface-
launched missiles.
In an antiair warfare (AAW) operation,
guided missiles are the second line of defense. The
first line of defense is aircraft. The AAW missiles
in the Navy’s current inventory include the
Standard and Sea Sparrow missiles.
STANDARD
The Standard family of missiles is one of the
most reliable in the Navy’s inventory. Entering
the fleet more than a decade ago, it replaced the
Tartar and Terrier missiles. The Standard missile
can be used against missiles, aircraft, and ships.
Some of the older guided-missile destroyers
(DDGs) and the Oliver Hazard Perry-class frigates
use the SM-1(MR) as a medium-range defense
weapon. The SM-2(MR) is a medium-range
defense weapon for Ticonderoga-class Aegis
cruisers, California- and Virginia-class cruisers,
Arleigh Burke-class destroyers, and Kidd-class
destroyers.
Characteristics of the SM-1(MR) and
SM-2(MR) missiles:
Length:
14 feet, 7 inches
Diameter:
13.5 inches
Wing span:
3 feet, 6 inches
Weight:
SM-1-1,100 pounds;
SM-2-1,380 pounds
Range:
More than 15 nautical miles
The SM-2(ER) is an extended-range area
defense weapon for the Leahy, Belnap,
Bainbridge, Truxton, and Long Beach classes of
cruisers.
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