The term radar is an acronym for the phrase
RAdio Detection And Ranging, and is used to describe systems
that use electromagnetic energy to detect distant objects and possibly
determine other characteristics such as direction and range.
Thomas Edison filed
a patent in 1885 for what appears to be the
earliest form of radar designed to avoid collisions at
sea. Interest was again excited in the concept of transmitting
electromagnetic waves over the surface of the earth in 1901
when Marconi demonstrated the transmission of electromagnetic signals across the
Atlantic . The British were pioneers in radar, realising
the potential of the science during the lead up to
World War II]. Operational radar systems were successfully employed
during World War II to assist with navigation and target
detection. Interestingly, the field of radar-related electronic warfare (EW)
was also born during this era as both German and
British engineers developed the earliest forms of chaff (called window
by the British). Radar theory and techniques continue to
develop rapidly from these early beginnings.
Radar is superior to
the human eye in a number of ways. Firstly, radar is able to "see" in conditions associated with poor
human visibility, including darkness, rain, fog, cloud and so on.
Radar also has the ability to "see" distances in
excess of the human eye and provide more precise measures
of target range, relative target velocity and target bearing (in
both azimuth and elevation).
The human eye has some advantages over
radar, however. The human eye has far better resolution
than radar systems in that the human eye can
resolve two targets even if they are very close together,
where radar systems may only see one large target.
Human eyes can also gather much more detailed visual information
on a specific target such as colour, shape, and texture.
The gap between radar and human eyes in terms
of resolution, in particular, is closing as advanced signal processing
techniques associated with modern radars push radar performance to
new heights.
Other topics in our resources on Radar related to Radar include: