ABSTRACT
The basic operation of a pulse radar is depicted in Figure 20.1. The radar transmits pulses superimposed on a
radio frequency (RF) carrier and then receives returns (reflections) from desired and undesired scatterers.
Scatterers corresponding to desired targets may include space, airborne, and sea-or surface-based vehicles.
They can also include the Earth’s surface and the atmosphere in remote sensing applications. Returns from
undesired scatterers are denoted as clutter. Clutter sources include the Earth’s surface, natural and man-made
discrete objects, the sea, and volumetric atmospheric phenomena such as rain and birds. Short-range/low-
altitude radar operation is often constrained by clutter since a multitude of undesired returns masks returns
from targets of interest such as aircraft. Conversely, volumetric atmospheric phenomena may be considered as
targets for weather radar systems. The magnitude of the clutter returns exceeds those from small targets by
multiple orders of magnitudes so a combination of angle, range, and Doppler filtering is required to extract
returns from targets of interest.
