12 Radar Systems of Maritime Transport
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constitute from 8 up to 20 s, depending on the probability of target observation. The
guard zone is disabled via the AUTO-PLOTTING/ZONE RESET menu.
When using ARPS, one should consider that over time from the moment the
target is locked-on for auto-tracking, the errors in parameters determining of target
movement in conditions of uniform and rectilinear movement of one’s own ship and
the target gradually decrease (the smoothing process is in progress) and after 3 min
the errors do not exceed the following values: in direction of relative movement (RM)
of target—2 ÷ 5°, in speed—0.3 ÷ 1 knot, in distance of shortest approach—0.5 ÷
0.7 miles (depending on approach direction and gyrocompass error), in true heading
of target—2.5 ÷ 7.5°, in true speed of target—0.8 ÷ 1.2 knots (depending on sonar
log error).
The abovementioned time delay in obtaining of the most accurate data on tracked
real targets is manifested in the fact that immediately after maneuvering own ship’s
course or speed, the parameters and vectors of targets movement can have 2–5 times
large errors, which with time of steady motion decrease to a stable low values.
The main indicator of the ARP mode is the stability of target tracking under
conditions of interference from hydrometeors and rough sea surface, as well as from
conditions of target position relative to other surface objects and the coast. By means
of adaptive processing of video signals, stable targets auto-tracking is provided under
various conditions of interference, even at small increase of target signal level over
the interference, i.e., provided that the target blip is barely distinguishable against
the background noise on the indicator screen.
ARPS provides targets classification based on motion parameters:
• moving targets (speed from 1.6 knots or more) have an auto-tracking symbol
(circle);
• maneuvering targets (or all targets—when maneuvering of own ship on a course
with a speed change of not more than 5%) have blinking AC symbols;
• stationary targets (speed of 1.5 knots or less) have an auto-tracking symbol—a
circle with a cross.
When the rendezvous parameters (DSA and TSA) of any target of dangerous
values are reached, the symbol of a threat (dangerous) target (triangle) appears, the
vector of its movement becomes flickering, and the message THREAT TARGET is
periodically generated, accompanied by a sound signal. The display of the trajectory
dots of the past movement of auto-tracked targets is carried out by the TRACE-DOTS
button on the control panel, and the selected mode is indicated on the screen’s panel
as DOT, next to the target logbook (label).
Trial maneuver. This mode is used to replay own ship’s maneuver for collision
avoidance with threat target. In case of decision making on maneuver, it should be
considered that maneuver calculations do not take into account the maneuvering and
dynamic characteristics of own ship. No AC functions are interrupted while playing
own ship’s avoidance maneuver by changing the simulated course and/or speed.
Active response mode in marine radar location. In maritime radar location, a
system designated as radar beacon transponder (RBT/Search And Rescue Radar
Transponder, SART) is used for position finding of ships in distress. RBT provides
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constitute from 8 up to 20 s, depending on the probability of target observation. The
guard zone is disabled via the AUTO-PLOTTING/ZONE RESET menu.
When using ARPS, one should consider that over time from the moment the
target is locked-on for auto-tracking, the errors in parameters determining of target
movement in conditions of uniform and rectilinear movement of one’s own ship and
the target gradually decrease (the smoothing process is in progress) and after 3 min
the errors do not exceed the following values: in direction of relative movement (RM)
of target—2 ÷ 5°, in speed—0.3 ÷ 1 knot, in distance of shortest approach—0.5 ÷
0.7 miles (depending on approach direction and gyrocompass error), in true heading
of target—2.5 ÷ 7.5°, in true speed of target—0.8 ÷ 1.2 knots (depending on sonar
log error).
The abovementioned time delay in obtaining of the most accurate data on tracked
real targets is manifested in the fact that immediately after maneuvering own ship’s
course or speed, the parameters and vectors of targets movement can have 2–5 times
large errors, which with time of steady motion decrease to a stable low values.
The main indicator of the ARP mode is the stability of target tracking under
conditions of interference from hydrometeors and rough sea surface, as well as from
conditions of target position relative to other surface objects and the coast. By means
of adaptive processing of video signals, stable targets auto-tracking is provided under
various conditions of interference, even at small increase of target signal level over
the interference, i.e., provided that the target blip is barely distinguishable against
the background noise on the indicator screen.
ARPS provides targets classification based on motion parameters:
• moving targets (speed from 1.6 knots or more) have an auto-tracking symbol
(circle);
• maneuvering targets (or all targets—when maneuvering of own ship on a course
with a speed change of not more than 5%) have blinking AC symbols;
• stationary targets (speed of 1.5 knots or less) have an auto-tracking symbol—a
circle with a cross.
When the rendezvous parameters (DSA and TSA) of any target of dangerous
values are reached, the symbol of a threat (dangerous) target (triangle) appears, the
vector of its movement becomes flickering, and the message THREAT TARGET is
periodically generated, accompanied by a sound signal. The display of the trajectory
dots of the past movement of auto-tracked targets is carried out by the TRACE-DOTS
button on the control panel, and the selected mode is indicated on the screen’s panel
as DOT, next to the target logbook (label).
Trial maneuver. This mode is used to replay own ship’s maneuver for collision
avoidance with threat target. In case of decision making on maneuver, it should be
considered that maneuver calculations do not take into account the maneuvering and
dynamic characteristics of own ship. No AC functions are interrupted while playing
own ship’s avoidance maneuver by changing the simulated course and/or speed.
Active response mode in marine radar location. In maritime radar location, a
system designated as radar beacon transponder (RBT/Search And Rescue Radar
Transponder, SART) is used for position finding of ships in distress. RBT provides