For rapid target acquisition and proper tracking,
the track radar beam must be parallel to the boresight
axis, which is referenced to the ship’s weapons system
by benchmarks. An appreciable error between the axis
along which the radar effectively receives the return
pulses (called the track receive or the TR axis) and the
axis along which the radar transmits (called the track
transmit or the TX axis) reduces the rapid acquisition
capability of the radar. An error between the TR axis
of the tracking radar and the axis of the CW illumi-
nator impairs Tartar missile performance by reducing
target illumination power.
Collimation of the Tartar radar consists of deter-
mining the error between the RF beam axis and the
boresight axis and the errors between the RF beams
themselves.
In addition to determining the relative positions of
the RF beam axis, collimation operations should en-
sure that
the angle-error signals are generated properly
in each quadrant when the antenna is off target axis,
the specified angle-error sensitivity of the angle
tracking circuitry is obtained, and
the beam pattern is symmetrical.
Figure 4-4 shows Tartar radar collimation axes.
Figure 4-4.—Tartar radar collimation axes.
RADAR COLLIMATION SHORE TOWERS
Radar collimation shore towers are designed pri-
marily to check antenna beam collimation and RF
characteristics of GMFCSs. They also provide facili-
ties for collimation and beacon checks of gunfire-
control radars and RF alignment (azimuth only) of the
three-coordinate search radars.
A radar collimation shore tower is 130 to 250 feet
high with a moveable array on which test antennas
and associated optical targets are mounted. Wave-
guide and coaxial transmission lines connect the an-
tennas on the tower array to an equipment room at the
base of the tower.
The equipment room contains all the test equip-
ment necessary to perform collimation and to check
RF characteristics on the various guided-missile/
gunfire-control radars and the three-coordinate search
radars found in the fleet. Figure 4-5 depicts a collima-
tion tower.
4-4
