We are all familiar with AIS signals being picked up by shore based stations and the positions being communicated to Marine Traffic. As ship based AIS transmissions are on VHF a digital frequency, range is limited depending on heights of antennas to around 30 Nm. This is fine for collision avoidance purposes but of limited value for open sea tracking. There is a procedure whereby vessels can make a manual position report to Marine Traffic by email but this is tedious on a daily basis and not often utilised.

Large merchant vessels with Class A transponders now have an option of position tracking by satellite which obviously removes the limitation of being within range of a shore station and Marine Traffic is now showing deep sea positions of such vessels.
 Does anyone know:
(a) if this is a subscription service or is it automatically provided by Marine Traffic, IMO or some other body?
(b) is it available for Class B transmitters?
(c) is there a mechanism whereby merchant vessels can re-transmit AIS positions received from other (Class B) vessels by satellite?
 

+x

 

John Franklin - 10/22/2020

We are all familiar with AIS signals being picked up by shore based stations and the positions being communicated to Marine Traffic. As ship based AIS transmissions are on VHF a digital frequency, range is limited depending on heights of antennas to around 30 Nm. This is fine for collision avoidance purposes but of limited value for open sea tracking. There is a procedure whereby vessels can make a manual position report to Marine Traffic by email but this is tedious on a daily basis and not often utilised.

Large merchant vessels with Class A transponders now have an option of position tracking by satellite which obviously removes the limitation of being within range of a shore station and Marine Traffic is now showing deep sea positions of such vessels.
 Does anyone know:
(a) if this is a subscription service or is it automatically provided by Marine Traffic, IMO or some other body?
(b) is it available for Class B transmitters?
(c) is there a mechanism whereby merchant vessels can re-transmit AIS positions received from other (Class B) vessels by satellite?
 

John,
Yes you can subscribe to individual vessel satellite AIS Marine Traffic Feeds. 
Satellite reception of Class B feeds is less reliable than class A but it is still satisfactory. We experimented with a free trial of this during the summer of 2018 when we were able to track all of those boats attempting to transit  the NWP. Unfortunately we were not able to relay those satellite derived positions to the OCC Fleet Map as we didn't have an API at that time. With the new vessel display system we are constructing this will be possible but a bulk subscription to satellite feeds is prohibitively expensive.
Simon