96
Reference section 6 — Radar
Radar cursor
Northstar 972
Radar cursor
If you press the cursor pad while on the
radar screen, a radar cursor is displayed.
You can move the cursor to any echo or
other point on the screen and read the
distance and bearing to it in the lower right
corner of the screen.
Press
Vessel
to remove the radar cursor
when done.
MARPA targets
The Miniature Automatic Radar Plotting
Aid (MARPA) target tracking system allows
you to designate displayed echoes as
targets
, which will be tracked automati-
cally as they move. Each target’s speed,
course-over-ground, closest point of
approach, etc. are calculated and displayed.
Targets are displayed on the radar image
with special symbols indicating their acqui-
sition status.
You can control how much data is
displayed for each target.
MARPA is used primarily for collision
avoidance in larger ships at ranges from
about 2 to 8 nautical miles, and in smaller
ships at ranges between 1/2 and 4 nautical
miles.
How does MARPA work?
MARPA works by continuously assessing a
target you have designated. As the vessel
pitches and rolls with the sea, the radar’s
view, the target’s shape and size, and the
ship’s heading will all vary. If you can’t see
the target on the radar, then the MARPA
feature can’t see it either.
The 972 has built-in intelligence that
compensates for all this variation and
makes every attempt to track MARPA
targets — even in difficult conditions.
A critical component in the operation of
the MARPA feature is your heading sensor.
The heading sensor provides MARPA with
critical information to correlate the radar
display with the ship’s heading. A poor
heading sensor can make MARPA a chal-
lenge even in good conditions.
Summary of Contents for 972
Page 1: ...Northstar 972 Quickstart Guide and Reference Manual Revision B ...
Page 12: ...8 Getting Started Purchasing charts Northstar 972 ...
Page 19: ...15 Displaying the chart screen Quickstart Guide Revision B Chart screen ...
Page 30: ...26 SAVE and Man Overboard MOB Northstar 972 ...
Page 54: ...50 Reference section 3 Position coordinates Using Phantom Loran Northstar 972 ...
Page 90: ...86 Reference section 6 Radar Transferring waypoints to and from a PC Northstar 972 ...
Page 106: ...102 Reference section 7 Echo sounding MARPA targets Northstar 972 ...
Page 130: ...126 Reference section 7 Echo sounding Troubleshooting the echo sounder Northstar 972 ...
Page 134: ...130 Reference section 8 Video Displaying video Northstar 972 ...
Page 148: ...144 Reference section 10 Networking Restrictions Northstar 972 ...
Page 158: ...154 Reference section 11 Setup Changing the time zone Northstar 972 ...
Page 164: ...160 Reference section 11 Appendix A Datum list Changing the time zone Northstar 972 ...
Page 168: ...164 Northstar 972 Notes ...
Page 169: ...Notes 165 Operator s Manual Revision B ...
Page 170: ...166 Northstar 972 Notes ...
Page 171: ...Notes 167 Operator s Manual Revision B ...
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