Chapter 12
Radar Systems of Maritime Transport
The widespread use of ship navigation radars ensures the navigation safety in low
or limited visibility, allows you to obtain a fix by the known coastal and floating
orientation points or using specially installed radar transponder beacons and provides
an automation of maritime navigation processes.
By using the passive system radar, it is possible, for example, to distinguish the
boundary between water and land. It is possible to determine the route of passing
ships, since the wake current temperature could be higher than the water temperature.
Depending on the structure of emitted (sounding) radar signals, there are
continuous-wave radars and pulse radars. Pulse radars are used to the vast majority
on the civil fleet vessels.
Pulse radar contains the following main elements that are shown in the block
diagram (Fig. 12.1).
The transmitter consists of two main units, a modulator and a microwave oscillator,
which is used as a magnetron.
The modulator, under the influence of sync pulses, depending on the range scales,
forms powerful triggering (actuating) pulses of a certain duration (in modern radars
τ tp = 0.07…1.0 µs), under the influence of which the microwave oscillator generates
powerful short radio pulses.
The antenna switch (polyplexer) provides switching of one antenna alternately to
the transmitter and receiver, protects (blocks) the input circuits of the receiver from
powerful sounding microwave pulses, both of its own transmitter and neighboring
radars, and closes the output circuits of transmitter when receiving signals, reflected
from targets.
Weak reflected pulses, received by the antenna, passing through the antenna
switch, come to receiver, where they are converted in frequency, amplified and
detected. The high sensitivity of receiver, capable of receiving short-term pulses
is realized on the basis of a superheterodyne receiver with an intermediate frequency
(usually 60 MHz). At this frequency, when using transistors or microcircuits, high
gain and wide bandwidth can be obtained.
© 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_12
209
Radar Systems of Maritime Transport
The widespread use of ship navigation radars ensures the navigation safety in low
or limited visibility, allows you to obtain a fix by the known coastal and floating
orientation points or using specially installed radar transponder beacons and provides
an automation of maritime navigation processes.
By using the passive system radar, it is possible, for example, to distinguish the
boundary between water and land. It is possible to determine the route of passing
ships, since the wake current temperature could be higher than the water temperature.
Depending on the structure of emitted (sounding) radar signals, there are
continuous-wave radars and pulse radars. Pulse radars are used to the vast majority
on the civil fleet vessels.
Pulse radar contains the following main elements that are shown in the block
diagram (Fig. 12.1).
The transmitter consists of two main units, a modulator and a microwave oscillator,
which is used as a magnetron.
The modulator, under the influence of sync pulses, depending on the range scales,
forms powerful triggering (actuating) pulses of a certain duration (in modern radars
τ tp = 0.07…1.0 µs), under the influence of which the microwave oscillator generates
powerful short radio pulses.
The antenna switch (polyplexer) provides switching of one antenna alternately to
the transmitter and receiver, protects (blocks) the input circuits of the receiver from
powerful sounding microwave pulses, both of its own transmitter and neighboring
radars, and closes the output circuits of transmitter when receiving signals, reflected
from targets.
Weak reflected pulses, received by the antenna, passing through the antenna
switch, come to receiver, where they are converted in frequency, amplified and
detected. The high sensitivity of receiver, capable of receiving short-term pulses
is realized on the basis of a superheterodyne receiver with an intermediate frequency
(usually 60 MHz). At this frequency, when using transistors or microcircuits, high
gain and wide bandwidth can be obtained.
© 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_12
209