All vessels with a running AIS transponder, which sail within the range of an AIS receiver station, are displayed on the FleetMon Explorer. If there is no current position update for the last 24 hours (for Open accounts the last 30 minutes) the vessel will disappear from the live map until we receive a new position.
With our terrestrial AIS receiver network, we can only cover specific areas where a shore-based AIS receiver station is installed. The remaining areas are covered underuse of Satellite-AIS.
There are some possible reasons why a vessel is not displayed on the FleetMon Explorer if you have only access to terrestrial AIS data:
- The vessel is in an area where it is captured by Sat-AIS only because it is not sailing within range of a shore-based AIS receiver station.
- The vessel is not carrying an AIS transponder, the transponder is turned off or the transponder is not working properly.
- The AIS transponder does not transmit the correct information, for example, the MMSI number is wrong, so the received AIS signals cannot match with the corresponding ship entry in our vessel database.
- The transmission power of the AIS transponder is too low for a shore-based AIS station to receive the signals (depending on the type of transponder, type, and height of the antenna).
- The vessel has a Class B AIS transponder on board and is sailing in a high traffic area. The transmission power of a Class B transponder is lower than the power of a Class A transponder. As long as the AIS station receives Class A signals, the reception of Class B signals is restricted.
If you have access to Sat-AIS with your account and still cannot see a vessel on the FleetMon Explorer the following reasons are likely:
- The vessel is sailing in a high traffic area, is not captured by a shore-based AIS receiver station and also the satellite does not receive a signal.
- The vessel is carrying a Class B receiver, which is more difficult to be captured by satellite.