Guy Kouemou, "Radar Technology"
InTech | 2010 | ISBN: N/A | ISBN-13: 9789533070292 | 410 pages | PDF | 51,5 MB
Preface
One of the most important inventions for the development of radars was made by
Christian Huelsmeyer in 1904. The German scientist demonstrated the possibility of
detecting metallic objects at a distance of a few kilometres. While many basic principles of
radar, namely using electromagnetic waves to measure the range, altitude, direction or
speed of objects are remained up to now practically unchanged, the user requirements and
technologies to realise modern radar systems are highly elaborated. Nowadays many
modern types of radar (originally an acronym for Radio Detection and Ranging) are not
designed only to be able to detect objects. They are also designed or required to track,
classify and even identify different objects with very high resolution, accuracy and update
rate.
A modern radar system usually consists of an antenna, a transmitter, a receiver and a
signal processing unit. A simple signal processing unit can be divided into parameter
extractor and plot extractor. An extended signal processing unit consists additionally of a
tracking module. The new category of signal processing units has also the possibility of
automatically target classification, recognition, identification or typing.
There are numerous classifications of radars. On the one hand they can be classified by
their platform as ground based, air borne, space borne, or ship based radar. On the other
hand they can be classified based on specific radar characteristics, such as the frequency
band, antenna type, and waveforms utilized. Considering the mission or functionality one
may find another categorization, such as weather, tracking, fire control, early warning, over
the horizon and more.
Other types are phased array radars, also called in some literatures as multifunction or
multimode radars (not necessary the same). They use a phased array antenna, which is a
composite antenna with at least two basic radiators, and emit narrow directive beams that
are steered mechanically or electronically, for example by controlling the phase of the
electric current.
Mostly radars are classified by the type of waveforms they use or by their operating
frequency....
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