Showing papers by "Geophysical Survey published in 1989"

Extraction of radar targets from clutter

Abstract: The extraction of radar targets, in particular airplanes or cruise missiles, from clutter is typically based on the target's velocity relative to the ground. Equipment using this principle is usually referred to as a doppler processor or moving target indicator. In situations where severe clutter is encountered, as for example where a look-down radar is trying to find low-flying cruise missiles, extraction of the target solely through its velocity relative to the ground is generally unsatisfactory. A similarly situated human observer looking down can recognize a target both from its motion and the characteristic shape of a fuselage with wings. The principle of this "shape recognition" or "pattern recognition" is here applied to radar by utilizing the so-called radar signature of the target. The conventional small-relative-bandwidth radar which uses signals that are amplitude modulated onto a sinusoidal carrier does not yield enough of a radar signature for this application but the so-called "carrier-free radar" does. Carrier-free radar is also known as "impulse radar", "nonsinusoidal radar", or "large-relative-bandwidth radar".