Standard Horizon CP500 owner manual Ais, AIS System Definitions

14. AIS

AIS is an Automatic Identification System. It has been introduced to improve the safety of navigation by assisting in the efficient operation of ship-to-ship location reporting and VTS applications. The system should enable operators to obtain information from the ship automatically, requiring a minimum of involvement of ship’s personnel, and should have a high level of availability. AIS transponders installed on IMO vessels use VHF frequencies to:

· Transmit details of their own vessel

· Receive details from other vessels or navigation aids within VHF range.

Information being transmitted from vessels over 300 tons that, due to recent worldwide legislation, are required to fit Class “A” AIS transponders.

Connecting to the GPS Chart Plotter an AIS receiver (please contact your local dealer), will display vessels with AIS transponder within VHF range on screen giving the skipper or navigator a visual interpretation of the data of nearby vessels. This improves safety, and specifically for collision avoidance reasons.

14.0AIS SYSTEM DEFINITIONS

·Target: It is a vessel equipped with AIS. Information about the targets is being received by AIS Receiver and displayed on the screen.

·CPA: Closest Point of Approach is the closest distance that will be achieved between your vessel and the tracked target, based on your vessel’s speed and direction and the target’s speed and direction.

·CPA Limit: This is the distance from your vessel that a target may reach before a target is deemed a threat.

·CPA Alarm: Occurs if CPA is less or equal to CPA Limit. This test is done for active targets only.

·TCPA: Time to closest Point of Approach is the time remaining until the CPA will occur.

·TCPA Limit: This is the time remaining before the CPA is reached.

·TCPA Alarm: Occurs if TCPA is less or equal to TCPA Limit. This test is done for active targets only and if CPA value is less or equal to CPA Limit.

·Radio Call Sign: International call sign assigned to vessel, often used on voice radio.

·Name: Name of ship, 20 characters.

·MMSI: Maritime Mobile Service Identity.

·MMSI number: A unique 9 digit number that is assigned to a DSC radio station. It primarily registers the boat information in the U.S. Coast Guard’s national distress database for use in emergency situations.

·Active Target: Target located within the Activation Range. Active target is represented by oriented triangle with COG and Heading vectors. Rate of turn may also be displayed.

·Dangerous Target: Target detected by CPA or TCPA Alarm. Dangerous target is Active Target by definition. For better visibility Dangerous Target symbol is flashing.

·Sleeping Target: Target located outside the Activation Range. Sleeping target is represented by a small oriented triangle.

·Lost Target: When the AIS info is not received from that vessel for 3.5 minutes. The presentation will be a flashing black triangle with a cross through.

·Activation Range: Range around your boat where targets become active. AIS target become active within this range. Activation Range should be greater than CPA Limit by definition.

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