Raymarine RayTech RNS 5.0, Руководство пользователя

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Chapter 7: Using radar 55
To place the second VRM/EBL pair:
1. Click the
MORE
softkey on the VRM/EBL 1 softkey bar. The softkeys for VRM/EBL 2
will be displayed.
2. Repeat steps 2 through 8 above. The VRM/EBL will be placed at a location 2/3 of
current range and a bearing of 330
o
.
MARPA
Safety Notices
CAUTION: MARPA can improve collision avoidance when used wisely.
It is the user’s responsibility to exercise common prudence and
navigational judgement.
There are conditions where acquiring a target may become difficult. These same
conditions may be a factor in successfully tracking a target. Some of these conditions
are:
• The target echo is weak. The target is very close to land, buoys or other large
targets.
• The target or your own boat is making rapid maneuvers.
• Choppy sea state conditions exist and the target is buried in excessive sea clutter or
in deep swells.
• Choppy sea state conditions exist yielding poor stability; own boat’s heading data
is very unstable.
• Inadequate heading data.
Symptoms of such conditions are that acquisition is difficult, and the MARPA vectors
are unstable; the symbol wanders away from the target, locks on to another target or
changes to a lost target symbol.
If any of these conditions are present, acquisition and tracking may need to be re-
initiated or, in some cases be impossible to maintain. Improving the quality of the
heading data will reduce the effect of the other conditions.
What is MARPA?
You can use the Mini Automatic Radar Plotting Aid (MARPA) functions for target
tracking and risk analysis. MARPA improves collision avoidance by obtaining detailed
information for up to 10 automatically tracked targets and provides continuous,
accurate and rapid situation evaluation.
MARPA automatically tracks acquired targets, calculates target bearing and range,
true speed and course, Closest Point of Approach (CPA) and Time to Closest Point of
Approach (TCPA).