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12 Radar Systems of Maritime Transport
• provide manual switching-on and switching-off, indication in standby mode, have
a floating lanyard;
• withstand dropping into water from a height of 20 m;
• be waterproof to a depth of 10 m for at least 5 min;
• be equipped with visual or alerting sound systems to determine normal operation
and warn those in distress that the RBT has been activated by the radar;
• have sufficient battery capacity to operate in standby mode for 96 and 8 h with
continuous exposure to 1 kHz radar pulses;
• maintain performance in the temperature range from—20° up to +55 °C;
• the height of RBT installation should be at least 1 m above the sea surface;
• be triggered at a distance of up to 5 miles when irradiated by a radar with an
antenna height of 15 m and when irradiated by an aircraft radar with 10 kW
power at a distance of up to 30 miles from an altitude of 1000 m.
Parallel index method. Modern radar stations are designed to detect surface objects
and shores in conditions of limited visibility, determine the location of the vessel,
ensure navigation in narrow areas, divergences with meeting vessels.
When sailing along the coast or in confined waters, it is necessary to carefully
monitor the movement of the vessel relative to the track line. This monitoring
should include periodic position fixes, which would be combined with continuous
monitoring of the ship’s transfer relative to the track line.
Continuous monitoring of the ship’s position relative to track line is possible using
the method of parallel index lines. These lines run through the entire screen circle
regardless of distance range used and are available in all display and movement
modes.
Parallel index lines are lines displayed on the radar screen parallel to the track
line and at a distance from the sweep center (vessel) equal to the specified distance
that is planned when passing the landmark (Fig. 12.7).
Further, we will consider the situation in the mode of relative display and
orientation relatively to the north.
The lines displayed on the radar screen do not change its direction and distance
relatively to the center of the sweep when changing a course.
In Fig. 12.8, plot of the map with the marked track direction equals to 220°. A
tangent line is drawn to the selected cape, which is parallel to the track line. The
distance from track to tangent line equals to 0.3 miles (see above Cape). The vessel
must navigate such a course that the distance between the tangent and the track line
remains constant.
On the radar screen, it will be as follows: The display of the track line is turned
on, the direction is set to 220°, and then it is shifted from the center by a distance
of 0.30 miles. Thus, the line that was set will remain in the originally set direction
and distance from the center of the sweep. When the vessel is moving, landmarks
move in the direction opposite to the movement of the vessel on the radar screen in
the mode of relative movement. Consequently, in our case, the cape will move. It is
12 Radar Systems of Maritime Transport
• provide manual switching-on and switching-off, indication in standby mode, have
a floating lanyard;
• withstand dropping into water from a height of 20 m;
• be waterproof to a depth of 10 m for at least 5 min;
• be equipped with visual or alerting sound systems to determine normal operation
and warn those in distress that the RBT has been activated by the radar;
• have sufficient battery capacity to operate in standby mode for 96 and 8 h with
continuous exposure to 1 kHz radar pulses;
• maintain performance in the temperature range from—20° up to +55 °C;
• the height of RBT installation should be at least 1 m above the sea surface;
• be triggered at a distance of up to 5 miles when irradiated by a radar with an
antenna height of 15 m and when irradiated by an aircraft radar with 10 kW
power at a distance of up to 30 miles from an altitude of 1000 m.
Parallel index method. Modern radar stations are designed to detect surface objects
and shores in conditions of limited visibility, determine the location of the vessel,
ensure navigation in narrow areas, divergences with meeting vessels.
When sailing along the coast or in confined waters, it is necessary to carefully
monitor the movement of the vessel relative to the track line. This monitoring
should include periodic position fixes, which would be combined with continuous
monitoring of the ship’s transfer relative to the track line.
Continuous monitoring of the ship’s position relative to track line is possible using
the method of parallel index lines. These lines run through the entire screen circle
regardless of distance range used and are available in all display and movement
modes.
Parallel index lines are lines displayed on the radar screen parallel to the track
line and at a distance from the sweep center (vessel) equal to the specified distance
that is planned when passing the landmark (Fig. 12.7).
Further, we will consider the situation in the mode of relative display and
orientation relatively to the north.
The lines displayed on the radar screen do not change its direction and distance
relatively to the center of the sweep when changing a course.
In Fig. 12.8, plot of the map with the marked track direction equals to 220°. A
tangent line is drawn to the selected cape, which is parallel to the track line. The
distance from track to tangent line equals to 0.3 miles (see above Cape). The vessel
must navigate such a course that the distance between the tangent and the track line
remains constant.
On the radar screen, it will be as follows: The display of the track line is turned
on, the direction is set to 220°, and then it is shifted from the center by a distance
of 0.30 miles. Thus, the line that was set will remain in the originally set direction
and distance from the center of the sweep. When the vessel is moving, landmarks
move in the direction opposite to the movement of the vessel on the radar screen in
the mode of relative movement. Consequently, in our case, the cape will move. It is