How many guard rings do ARPA alarms use?

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Multiple Choice

How many guard rings do ARPA alarms use?

ARPA alarms use two guard rings around your vessel to provide two levels of alert. The inner ring marks an immediate collision threat—when a contact enters this zone, an alarm fires right away. The outer ring defines a caution zone—if a target is inside this ring but outside the inner one, you get a warning that you should monitor and possibly act, but it isn’t an urgent threat. This two-ring setup helps distinguish near-term danger from potential risk and reduces nuisance alarms, giving you time to assess and respond. The rings are concentric and centered on your ship, with distances adjustable based on speed, maneuverability, and safety margins.

ARPA alarms use two guard rings around your vessel to provide two levels of alert. The inner ring marks an immediate collision threat—when a contact enters this zone, an alarm fires right away. The outer ring defines a caution zone—if a target is inside this ring but outside the inner one, you get a warning that you should monitor and possibly act, but it isn’t an urgent threat. This two-ring setup helps distinguish near-term danger from potential risk and reduces nuisance alarms, giving you time to assess and respond. The rings are concentric and centered on your ship, with distances adjustable based on speed, maneuverability, and safety margins.

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