Chapter 3
Radar Targets and Its Reflecting
Properties
3.1 Types of Radar Targets
The range of radar surveillance, measuring of coordinates and obtaining of other
characteristics of target depend not only on technical characteristics of a radar, but
on reflecting properties of a target itself.
The physical subject matter of reflection consists in that the radar electromagnetic wave excites high-frequency current in radiated object: conduction current—
in metals; bias (displacement) current—in dielectric material. Herewith, the target
itself becomes an independent source of electromagnetic energy radiation (or reradiator [intermediate emitter] of electromagnetic wave radiating it) in space directions including into direction to the radar. An observer of this wave wherever positioned reads this wave as “reflected from a target,” considering it as “scattered wave”
in all other directions. Radio wave scattering (reflection) depends first of all on
geometric dimensions and shaping of a target, its coating structure and material, and
movement (deflection) behavior relatively to the radar as well.
Radar targets depending on geometric dimensions and surveillance types are
divided into point and distributed targets.
To point target from a position of an observer refers a target, which depending
on output signal in terminal (output) radar unit, does not permit to evaluate both
dimensions and details of a target and its amount as well. In radar display, such
target in the most cases gives a blip in a form of luminous dot that has defined its
name—a “point” target.
It is clear that target classification relying on surveillance device characteristics
has a far from absolute character. Jumping a little bit ahead (more closely this issue
will be examined further), let us introduce a term of resolution capability of radar
station.
The main approximation consists in that radar antenna radiates into a space a some
“bunch” of electromagnetic energy of finite size representing a some of parallelepiped
two sides length of which equals a = Dα and b = Dβ, where D is a distance
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
D. A. Akmaykin et al., Theoretical Foundations of Radar Location
and Radio Navigation, Springer Aerospace Technology,
https://doi.org/10.1007/978-981-33-6514-8_3
15
Radar Targets and Its Reflecting
Properties
3.1 Types of Radar Targets
The range of radar surveillance, measuring of coordinates and obtaining of other
characteristics of target depend not only on technical characteristics of a radar, but
on reflecting properties of a target itself.
The physical subject matter of reflection consists in that the radar electromagnetic wave excites high-frequency current in radiated object: conduction current—
in metals; bias (displacement) current—in dielectric material. Herewith, the target
itself becomes an independent source of electromagnetic energy radiation (or reradiator [intermediate emitter] of electromagnetic wave radiating it) in space directions including into direction to the radar. An observer of this wave wherever positioned reads this wave as “reflected from a target,” considering it as “scattered wave”
in all other directions. Radio wave scattering (reflection) depends first of all on
geometric dimensions and shaping of a target, its coating structure and material, and
movement (deflection) behavior relatively to the radar as well.
Radar targets depending on geometric dimensions and surveillance types are
divided into point and distributed targets.
To point target from a position of an observer refers a target, which depending
on output signal in terminal (output) radar unit, does not permit to evaluate both
dimensions and details of a target and its amount as well. In radar display, such
target in the most cases gives a blip in a form of luminous dot that has defined its
name—a “point” target.
It is clear that target classification relying on surveillance device characteristics
has a far from absolute character. Jumping a little bit ahead (more closely this issue
will be examined further), let us introduce a term of resolution capability of radar
station.
The main approximation consists in that radar antenna radiates into a space a some
“bunch” of electromagnetic energy of finite size representing a some of parallelepiped
two sides length of which equals a = Dα and b = Dβ, where D is a distance
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
D. A. Akmaykin et al., Theoretical Foundations of Radar Location
and Radio Navigation, Springer Aerospace Technology,
https://doi.org/10.1007/978-981-33-6514-8_3
15