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发表于 2011-11-20 16:54:59
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本帖最后由 Ragnarok 于 2011-11-20 22:44 编辑
http://en.wikipedia.org/wiki/Brevity_code
Notch
All aspect missile defensive maneuver to place threat radar/missile on the beam. Modern pulse-doppler radars remove ground clutter by filtering out returns from stationary objects; putting the threat on the beam permits the defending aircraft to be confused with ground returns and hence disappear from the threat radar. (Direction)
Beam/beaming
Target stabilized within 70 to 110 degree aspect; generally (direction) given with cardinal directions: east, west, north, or south
OPERATIONAL BREVITY WORDS, DEFINITIONS, AND COUNTERAIR (AFTTP 3-1.1)
NOTCH(ING) (w/direction)—Directive (informative) for an all-aspect missile defensive
maneuver to place threat radar/missile near the beam.
BEAM (w/cardinal direction)—Target stabilized within 70 to 110 degrees of aspect;
generally given in cardinal directions: east, west, north, and south.
lockon_fc2_flight_manual_en
The rate of closure of the surrounding terrain effectively generates a primary "notch" in the radar's
sensitivity, due to ground-reflected signals ("clutter") received along the axis of the main radar beam.
Target signals in this "look down clutter notch" are rejected by filtering as if they were ground clutter,
allowing beaming targets to break a radar lock. Antenna focusing is never perfect, however, and
some transmitted energy also spills out in unintended directions called sidelobes. This energy can
also be reflected from the ground, and re-enter the antenna from the sidelobe directions. If a fighter
is flying at low altitude, signals reflected from the ground may enter the radar and appear on the
scope as additional clutter, with a closure equal to the fighter's rate of climb or descent, and a range
equal to the fighter's altitude. If the fighter is in pursuit against a fleeing target travelling at the same
speed and range, the target signals may become lost in sidelobe clutter, breaking the lock. This can
create a secondary "notch" in the fighter's radar sensitivity.
旁瓣notch在CN101的一个帖子里有说到:http://falcon4.uueasy.com/read.php?tid=363&page=1&toread=1#tpc
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