User's Manual

Table Of Contents
Synapsis Radar
with Nautoscan NX Pedestal
Operator Manual
Edition July 2015
3-15
4265.DOC020102
3.4 Automatic Radar Plotting Aid (ARPA)
The purpose of an Automatic Radar Plotting Aid (ARPA) is to interpret Radar
information continuously and to display the results so that watch officers may
quickly assess and react to potential danger. The performance specification of
the International Maritime Organization (IMO) requires the ARPA plotting
reliability to be as good as manual plotting techniques. The NSC meets and
exceeds these minimum requirements to provide a greater margin of safety.
The first requirement of safety is to maintain surveillance of traffic and
navigation hazards. The ARPA will plot up to 40 automatically and 40 manually
acquired (Plot) targets.
For any targets being plotted, the ARPA continuously displays vectors
indicating speed and course. Based on preset conditions the ARPA determines
if the possibility for collision exists.
When a potentially dangerous target is detected, warnings are given and
information detailed on the target is displayed.
If the watch officer determines that an avoidance maneuver is required, the
ARPA trial maneuver mode can assist in the planning. When a maneuver is
actually made, the ARPA continuously displays the effect on all plotted targets
during and after the course change.