Defining a Circular Guard Zone
Before you can define the boundaries of the guard zone, you must enable a guard zone (
).
You can define a circular guard zone that completely surrounds your boat.
1 From a radar screen, select Menu > Radar Options > Guard Zone >
> Circle.
2 Select the location of the outer guard zone circle.
3 Select the location of the inner guard zone circle to define the width of the guard zone.
Defining a Partial Guard Zone
Before you can define the boundaries of the guard zone, you must enable a guard zone (
).
You can define the boundaries of a guard zone that does not completely surround your boat.
1 From a radar screen, select Menu > Radar Options > Guard Zone >
> Corner 1.
2 Touch and drag the location of the outer guard-zone corner .
3 Select Corner 2.
4 Select the location of the inner guard-zone corner to define the width of the guard zone.
5 Select Done.
MARPA
Mini-automatic radar plotting aid (MARPA) enables you to identify and track targets and is primarily used for
collision avoidance. To use MARPA, you assign a MARPA tag to a target. The radar system automatically
tracks the tagged object and provides you with information about the object, including the range, bearing,
speed, GPS heading, nearest approach, and time to nearest approach. MARPA indicates the status of each
tagged object (acquiring, lost, tracking, or dangerous), and the chartplotter can sound a collision alarm if the
object enters your safe zone.
Before you can use MARPA, you must have a heading sensor connected and an active GPS signal. The heading
sensor must provide the NMEA 2000 parameter group number (PGN) 127250 or the NMEA 0183 HDM or HDG
output sentence.
Radar
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