<s>
Marine	B-Algorithm
radars	I-Algorithm
are	O
X	B-Algorithm
band	I-Algorithm
or	O
S	B-Algorithm
band	I-Algorithm
radars	B-Application
on	O
ships	O
,	O
used	O
to	O
detect	O
other	O
ships	O
and	O
land	O
obstacles	O
,	O
to	O
provide	O
bearing	O
and	O
distance	O
for	O
collision	B-Protocol
avoidance	I-Protocol
and	O
navigation	O
at	O
sea	O
.	O
</s>
<s>
They	O
are	O
electronic	O
navigation	O
instruments	O
that	O
use	O
a	O
rotating	O
antenna	O
to	O
sweep	O
a	O
narrow	O
beam	O
of	O
microwaves	O
around	O
the	O
water	O
surface	O
surrounding	O
the	O
ship	O
to	O
the	O
horizon	O
,	O
detecting	O
targets	O
by	O
microwaves	O
reflected	O
from	O
them	O
,	O
generating	O
a	O
picture	O
of	O
the	O
ship	O
's	O
surroundings	O
on	O
a	O
display	B-Device
screen	I-Device
.	O
</s>
<s>
Radar	B-Application
is	O
a	O
vital	O
navigation	O
component	O
for	O
safety	O
at	O
sea	O
and	O
near	O
the	O
shore	O
.	O
</s>
<s>
In	O
addition	O
to	O
vessel-based	O
marine	B-Algorithm
radars	I-Algorithm
,	O
in	O
port	O
or	O
in	O
harbour	O
,	O
shore-based	O
vessel	O
traffic	O
service	O
radar	B-Application
systems	I-Application
are	O
used	O
by	O
harbormasters	O
and	O
coast	O
guard	O
to	O
monitor	O
and	O
regulate	O
ship	O
movements	O
in	O
busy	O
waters	O
.	O
</s>
<s>
Radars	B-Application
are	O
rarely	O
used	O
alone	O
in	O
a	O
marine	O
setting	O
.	O
</s>
<s>
A	O
modern	O
trend	O
is	O
the	O
integration	O
of	O
radar	B-Application
with	O
other	O
navigation	O
displays	O
on	O
a	O
single	O
screen	O
,	O
as	O
it	O
becomes	O
quite	O
distracting	O
to	O
look	O
at	O
several	O
different	O
screens	O
.	O
</s>
<s>
Therefore	O
,	O
displays	O
can	O
often	O
overlay	O
an	O
electronic	O
GPS	O
navigation	B-Application
chart	I-Application
of	O
ship	O
position	O
,	O
and	O
a	O
sonar	B-Application
display	O
,	O
on	O
the	O
radar	B-Application
display	O
.	O
</s>
<s>
In	O
commercial	O
ships	O
,	O
radars	B-Application
are	O
integrated	O
into	O
a	O
full	O
suite	O
of	O
marine	O
instruments	O
including	O
chartplotters	O
,	O
sonar	B-Application
,	O
two-way	O
marine	O
radio	O
,	O
satellite	O
navigation	O
(	O
GNSS	O
)	O
receivers	O
such	O
as	O
the	O
US	O
Global	O
Positioning	O
System	O
(	O
GPS	O
)	O
,	O
and	O
emergency	O
locators	O
(	O
SART	O
)	O
.	O
</s>
<s>
With	O
digital	O
data	B-General_Concept
buses	I-General_Concept
to	O
exchange	O
data	O
,	O
these	O
devices	O
advanced	O
greatly	O
in	O
the	O
early	O
21st	O
century	O
.	O
</s>
<s>
As	O
required	O
by	O
COLREGS	O
,	O
all	O
ships	O
shall	O
maintain	O
a	O
proper	O
radar	B-Application
lookout	O
if	O
it	O
is	O
available	O
on	O
board	O
to	O
obtain	O
early	O
warning	O
of	O
risk	O
of	O
collision	O
.	O
</s>
<s>
Radar	B-Application
plotting	O
with	O
the	O
use	O
of	O
an	O
EBL	O
and	O
VRM	O
,	O
or	O
the	O
ARPA	B-Algorithm
should	O
be	O
used	O
to	O
get	O
the	O
information	O
of	O
movement	O
and	O
the	O
risk	O
of	O
collision	O
(	O
bearing	O
,	O
distance	O
,	O
CPA	O
(	O
closest	O
point	O
of	O
approach	O
)	O
,	O
TCPA	O
(	O
time	O
of	O
closest	O
point	O
of	O
approach	O
)	O
of	O
other	O
ships	O
in	O
vicinity	O
.	O
</s>
<s>
Marine	B-Algorithm
radar	I-Algorithm
systems	O
can	O
provide	O
very	O
useful	O
radar	B-Application
navigation	O
information	O
for	O
navigators	O
on	O
board	O
ships	O
.	O
</s>
<s>
The	O
ship	O
's	O
position	O
could	O
be	O
fixed	O
by	O
the	O
bearing	O
and	O
distance	O
information	O
of	O
a	O
fixed	O
,	O
reliable	O
target	O
on	O
the	O
radar	B-Application
screen	O
.	O
</s>
<s>
Marine	B-Algorithm
radar	I-Algorithm
has	O
performance	O
adjustment	O
controls	O
for	O
brightness	O
and	O
contrast	O
,	O
also	O
manual	O
or	O
automatic	O
adjustment	O
of	O
gain	O
,	O
tuning	O
,	O
sea	O
clutter	O
and	O
rain	O
clutter	O
suppression	O
,	O
and	O
interference	O
reduction	O
.	O
</s>
