21. AIS Target Functions
21-2
Additionally the AIS transponder receives messages other than messages from ships:
• AIS Base station
• AIS on airborne SAR craft
• AIS on ATON (AIS aid to navigation)
There can be several hundreds or several thousands AIS targets, and of those only a few will be significant for your
ship. To remove unnecessary AIS targets from the ECDIS display, the feature "active and sleeping AIS targets" is
available. Initially any new AIS target received by an AIS transponder is not-active (="sleeping"). Such non-active
targets are shown with a small triangle. The operator can pick any AIS target and change it from non-active to
active. Active AIS targets are shown with a large triangle with speed vector, headline, rot indicator, etc. Further, the
operator can pick active AIS targets and change their status to non-active.
An indication of AIS target display capacity limit is given well before it is reached. When 95% of the operator-set
limit is reached for displayed AIS targets, the alert "636 AIS display 95% full" appears. When the operator-set limit
is reached, the alert "637 AIS display 100% full" appears.
An indication of AIS target processing capacity limit is given well before it is reached. The alert "638 AIS storage
95% full" is given when 95 percent of 1,500 targets are in the storage buffer and the alert "639 AIS storage 100%
full" is given when 1,500 targets or more are in the storage buffer.
ECDIS generates AIS-related alerts and these are "Alert 632: AIS Dangerous target" and "Alert 633: Lost AIS
target". Only active AIS targets generate alerts. The operator can enable or disable AIS target alerts as desired. The
feature "active and sleeping AIS targets" is very effective for focusing on only those AIS targets which need
supervision. The ECDIS further eases the task of the operator by automatically changing non-active targets to active
targets, if they meet the dangerous target limits set by CPA and TCPA.
To Next Page
Loading...
