Which are the possible sources for positional data?

As you browse MarineTraffic, you may come across the term Source that defines the origins of the incoming positions of any vessel. For a practical example, whenever you are searching for the recorded positions of any vessel at MarineTraffic, you can use the Source filter to define whether you want to view:

  • Positional data from any source (All)
  • Terrestrial data only (Terr-AIS)
  • Satellite data only (Sat-AIS)
  • Inmarsat-C data only (Inmarsat-C)

(Note that the available filtering options may differ depending on your subscription plan)


Let's have a brief look at the various positional data sources:

Terrestrial AIS (Terr-AIS or T-AIS)

The term refers to AIS signals that have been picked-up by terrestrial AIS receivers installed mainly around coastal areas worldwide. All these terrestrial stations comprise the MarineTraffic Network - keep in mind that anyone can contribute to the collection of AIS data

The advantage of terrestrial AIS is that the information is updated at frequent intervals provided that the subject vessel is sailing within the range of an AIS-receiving station. The range limitation is the main disadvantage of T-AIS as it is impossible to track vessels sailing in the deep seas or in remote areas where there is no terrestrial coverage available.

Satellite AIS (Sat-AIS or S-AIS)

Satellite-AIS comes as an ideal supplement to T-AIS. In partnership with ORBCOMM, the leading Satellite AIS provider, AIS signals get picked-up by next generation OG2 satellites. S-AIS offers the competitive advantage of deep sea tracking so that even ocean-going vessels can be tracked! However, the update intervals are scarcer compared to T-AIS.

Make sure to check the available Satellite AIS products to take your tracking capabilities to the next level with seamlessly fused AIS data from terrestrial and satellite sources!


Inmarsat-C data reports can also be enabled to provide vessel owners and operators with guaranteed coverage at regular intervals by utilising the existing Inmarsat-C terminal of the subject vessel. Upon activation of the Inmarsat-C polling service, it is possible to retrieve exact positions even if there is no incoming AIS position during a user-predefined interval. This way, you can rest assured that there will be at least one position report during the set interval. 

Self-reporting tools

Positional data can also be sent to MarineTraffic using self-reporting tools such as the OnCourse mobile application, even if a vessel is not equipped with an AIS transponder! So, if you are the owner of a small boat, make sure to check the alternative ways of reporting positions to MarineTraffic.