Radar System Engineering

SEC.315] STRUCTURES 99
example, the contours of the land are indicated partly by shading, partly
by true shadows. The identification of hills through intensity shading
depends largely upon the radar operator. There is a natural tendency on
the part of theoperator tosetthe gain too high, raising all groundsignals
to saturation and making small variations in intensity indistinguishable.
N
FI~. 325-Mouth of the SusquehannaRilcr at Havrc de GIWC, lfd. Bll]l(iings of
Edgewood Arsenaland.\herdeenPro\,ingGrour]dalevibible as bright patcllesst]~]tt1of the
electrifiedrailwayline. lYavelength 1,25cIll,0.80bcalll,altitude4000ft, radiuslOnautlcal
mi. 39”32’N. 76”13’W.
3.15. Structures.-The general appearance of structures and clusters
of buildings is illustrated in Fig. 3.25, which was obtained with a highresolution
system in the region betlvccn Baltimore and Havre de Grace,
Md. The most prominent single feature is the curved line of the Pennsylvania
Railroad. Bridges over t\vo branches stand out, in sharp contrast,
with the water. Southwest of the position of the aircraft, near the