Fighter Combat - Tactics and Maneuvering

FIGHTER WEAPONS
The various forms of horning guidance generally offer improved capability
against airborne targets, especially highly maneuverable targets. More
efficient trajectories and better guidance accuracy in the critical terminal
phase of the intercept are often available. Each guidance method, however,
has some advantage over the others in certain situations, so combination
systems are sometimes employed. An example is the use of preset or
command guidance during the early portion of a long-range shot to get the
missile close enough to the target to allow passive or active homing.
Advances in solid-state electronics technology have made it practical to
place more sophisticated guidance and sensor capability in small, lightweight
missile packages.
Missile Seekers
The seeker system of a missile is responsible for sensing and tracking the
target and providing the information necessary for performance of the
guidance system. Preset and command guidance do not require a seeker in
the missile, since the tracking function is accomplished by the launching/guidance
platform. Beam-rider missiles usually have a receiver in the
tail to collect information from the host guidance/tracking beam. Passive
missiles generally require a sensor receiver in the nose, as do semi-active
homers; but semi-active homers may also include a rear receiver for
interception of information directly from the illuminating platform which
can be compared to the reflected energy received by the forward sensor to
derive additional guidance data. Active homers require both a transmitter
and a receiver, generally located forward.
The maximum range of its seeker operation often limits the effective
range of a missile system. Passive seekers have an inherent advantage here,
because their received power is inversely proportional to the square of the
target range, while the max-range of active and semi-active systems varies
inversely with the fourth power. Several other factors also are involved.
For passive systems these include the intensity of the target radiation in
the direction of the sensor, the type of radiation (which determines the rate
of signal attenuation by the atmosphere), and the seeker sensitivity. For
active and semi-active systems maximum range depends on, in addition to
transmitted power and receiver sensitivity, the reflective characteristics of
the target relative to the type of illumination used. These reflective characteristics
are usually sensitive to target size, and also to the target's construction
material, shape, surface contours, and aspect, all of which may
combine to increase or decrease reflectivity.
The most common passive seeker now in use is the heat seeker. This
device contains a material (the detector) which is sensitive to heat (infrared—IR—radiation)
that is produced primarily by the target's propulsion
system. The detector is often cryogenically cooled to eliminate
internally generated thermal "noise" and allow detection of even very
small amounts of IR energy coming from an external source. The seeker
must still have the capability to discriminate between target radiation and
background radiation, however. Such differentiation is essential for all
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