JP 3-50 National Search and Rescue Manual Vol I - US Navy

to minimize clutter. While this is not critical with surface
vessel radar where a full 360 degrees of azimuth is usually
covered, it is an important factor in airborne radar searches.
b. Display adjustments. Whenever possible while en
route to the search area, the SRU should pass within radar
detection range of targets of opportunity to enable the radar
operator to estimate the expected detection range of the
search object under prevailing conditions.
c. Range scale. The radar display range scale should be
selected to accommodate no more than the maximum expected
detection range for the target, unless the radar must also be
used for navigation.
d. Antenna stabilization. When available, antenna
stabilization should be used to maintain a consistent surface
picture. Some radars have a ground-stabilized display mode
which improves detection performance with small targets.
Target echoes remain stationary while sea clutter fluctuates,
aiding the operator in distinguishing one from the other.
e. Search area atmospheric conditions. Whenever
possible, detailed weather information should be obtained to
help determine how inversion layers or other atmospheric
conditions will be expected to affect radar performance.
f. Search altitude. Generally, altitude should be kept
to a minimum considering safety and expected target detection
range. Low search altitudes tend to reduce "sea clutter" and
minimize the size of the blind zone beneath the aircraft in
SLAR searches. Search altitudes of less then 500 feet up to
1000 feet for FLAR, and 2000 to 3000 feet for SLAR, are the
most effective search altitudes for small targets (about one
square meter radar cross section is equivalent to a 16-foot
outboard). Larger targets require higher search altitudes to
the extent that horizon range is sufficient to achieve maximum
expected radar detection range.
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