There may be instances when an AIS-based event that had previously been displayed in Skylight, or was available via API, is no longer visible. As a near real-time system, Skylight displays the most up-to-date information available at the time. However, as additional updated AIS data is received or information processes are run, Skylight may learn that the event did not ultimately meet the requirements. In these rare instances, the event is removed from Skylight.
Vessel(s) involved in an event and later classified as equipment (buoy)
Skylight is designed to show events involving vessels. For example, a Standard Rendezvous shows where two vessels, transmitting AIS, have traveled in proximity at approximately the same speed. To avoid showing instances where gear that is transmitting AIS is involved in a Standard Rendezvous with its vessel, Skylight runs a daily process to identify and classify equipment.
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A vessel that has been classified as equipment will be viewable in the Vessel Details Screen, but there will be no events associated with the vessel after the buoy service is run since those events have been removed from Skylight.
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Dark Rendezvous marked as Duplicate
A vessel cannot be involved in a Dark Rendezvous and Standard Rendezvous at the same time. However, it’s possible that in Skylight a Dark Rendezvous is generated prior to a Standard Rendezvous being created for a vessel. Once the Standard Rendezvous is generated, the system will go back and mark the Dark Rendezvous as a duplicate and the event will no longer be available in the system.
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Out of Order AIS messages
One common reason an event is removed from Skylight is additional AIS data is received out of order and Skylight ‘learns’ the event did not actually meet the requirements. Although rare for most events, because of the nature of Potential Dark Activities, it is more likely that additional AIS data will come in out of order and change these events.
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