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F-16 C/D (APG-68)
The APG-68 pulse-doppler radar
meets the all-weather air superiority
and air-to-ground strike requirements
of the F-16 C/D fighter. Employing
both head-up (HUD) and cockpit dis-
plays, it provides the easy hands-on,
head-up operation essential for situa-
tion awareness in a one-man fighter.
Implementation. Consisting of
four air-cooled line-replaceable
units—antenna plus low-power RF
unit, transmitter, and processor—it
weighs 379 lbs., has a predicted mean
time between failures of 250 hours,
and a mean time to repair on the
flight line of 30 minutes.
The antenna is a planar array,
mounted in azimuth and elevation
gimbals. Rotation about the roll axis
is handled by suitably resolving the
azimuth and elevation drive and posi-
tion indicating signals.
A key feature of the transmitter is
use of a dual mode TWT to meet the
conflicting requirements of low peak
power for high-PRFs and high peak
power for medium PRFs.
The processor consists of a pro-
grammable signal processor and a
radar data processor in a single unit.
Operation. A complete set of air-
to-air, air-to-ground, and air-combat
modes is provided.
The principal air-to-air search
modes are a high-peak-power medi-
um-PRF, and, an alert/confirm mode
in which velocity search is used for
alert. When a target is detected, it is
confirmed on the next scan with an
optimized medium-PRF waveform. If
the target proves valid, it is presented
in a range versus azimuth display. In
both modes, the pilot can optionally
restrict the search to a particular
region of interest or request altitude
data on a given target.
Also provided are track-while-
scan for up to 10 targets, single-target
track, and a situation awareness mode
in which one or two pilot-selected
targets are tracked continuously while
the radar searches a pilot-selected vol-
ume. The radar also has a raid mode,
which analyses possible multiple tar-
gets for differential velocities; a long-
range up-look medium-PRF mode,
optimized for low to moderate clutter
environments; and a track retention
capability for coasting through peri-
ods of single-target tracking when the
signal drops below the clutter.
Air-to-ground modes include real-
beam mapping, in which “hard” tar-
gets are sharpened with a monopulse
technique; an expanded version of
this mode optimized for maritime
surveillance; and two doppler beam
sharpening modes, providing 6:1 and
64:1 azimuth resolution improve-
ment, respectively. Supplementing
The F-16 C/D Fighter
With air-to-air and air-to-
ground radar displays pre-
sented on the head-up display
(HUD) and all combat critical
radar controls built into the
throttle and side stick, the
pilot never needs to take his
eyes off a target or his hands
off the aircraft controls.
these are fixed target tracking, ground-
moving-target detection and tracking,
and beacon modes.
Air-combat modes are automati-
cally selected by pressing a “dog fight”
switch on the throttle. Initially, the
radar scans a 20° by 30° body-stabi-
lized field of view and locks onto the
first target detected within 10 nmi.
The pilot also has the options of (a)
selecting a 10° by 60° vertical scan,
(b) steering to place the cursor of the
HUD on the target and locking onto it
by releasing a designate switch on the
side stick, or (c) automatically acquir-
ing a target anywhere within the
antenna scan limits.
Growth. The APG-68 has suffi-
cient throughput to support the addi-
tion of SAR, terrain following, terrain
avoidance, PVU, PPU and other
advanced modes.
The radar’s four air-cooled
LRUs are organized for min-
imum interconnection and
ease of maintenance. Each
has its own power supply
and BIT.
Fighter & Attack
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