Radar System Engineering

192 THE GATHERING AND PREti’ENTA TION OF RA DAR DATA [SEC. 6.12
track of refraction conditions by talking to pilots of aircraft seen on the
radar, and checking radar height readings with their altimeters.
Combined Plan and Height Systems.—Despite the speed, convenience,
and accuracy of the elevation-scanning height finders just described, these
sets are merely auxiliary to a search radar. Equipments that provide
plan and height information continuously on all targets in the field of
view, using a single antenna system, are obviously preferable. The
limitations discussed in Chap. 4 on the range out to which a substantial
area can be rapidly scanned preclude the design of a single radar system
which will gi~,e both plan and height information with the necessary
accuracy, as often as is desirable, and out to a range limited only by the
optical horizon.
Two or more radar systems can
be combined to allow continuous
and rapid indication of both plan
position and height of all targets in
the field of view. One example of
such a radar is a ship~based set
which combines a conventional PPI
radar with an elevation-scan height
finder of advanced design.
Another, working on quite a different
principle, is the V-beam radar,
GroundrangeInmiles
which reduces the measurement of
FIG, 6,24.—Calibration of beigbt readings
of .4N/TPS-10.
height to two measurements of target-azimuth.
The ship radar uses a search set and a height finder whose antennas
occupy the same pedestal. The search set has a beamwidth in azimuth
of 1.5° and elevation coverage up to 15°. The height finder antenna is
15 ft high by 5 ft wide, fed at 8.9-cm wavelength by a special feed (Sec.
9.16) which can cause the beam to scan at ten oscillations per second.
The beamwidth in elevation is 1” and in azimuth 4°. The height finder
antenna feed is so arranged that the pulses are distributed uniformly
throughout the angle of scan, and not concentrated at the upper and
lower angles as they are by the mechanical oscillation used in the sets just
described. As a result, the antenna can be rotated at 4 rpm and heightfinding
to a range of 50 statute miles is quite possible. A 12° range of
elevation angle can be covered.
The antenna is shown in Fig. 9.31. The display console is shown in
Fig. 6.25. A three-fold indication scheme is used. One indicator gives
the general PPI picture and a second gives an expansion in range and
azimuth angle which enables detailed control to be accomplished. The
third indicator is a range-height indicator. The RHI is brightened for a