Inmarsat C I-4 Migration

On 16 April 2018, at 10:00UTC, Inmarsat will migrate traffic from its Inmarsat C service I-3 to I-4. Some Pole Star services may be affected.

Important Information for Inmarsat Customers

As you may be aware, the Inmarsat-3 (I-3) constellation of satellites are reaching the end of their lifespan, which has made it necessary for Inmarsat to roll out the end of life process for several of their legacy services, and to migrate those that will continue onto Inmarsat-4 (I-4). One such service to be migrated is Inmarsat C. From end End Q1 2018, Inmarsat will migrate traffic from its Inmarsat C service from I-3 to I-4.

On 16 April 2018, at 10:00UTC, Inmarsat will migrate traffic from its Inmarsat C service I-3 to I-4, starting with the Atlantic Ocean Region West (AOR-W) first.

This migration applies to all users of Inmarsat C, and is not initiated or controlled by Pole Star - however we realise this may affect some of our customers, particularly those who rely on our vital maritime safety and vessel tracking and positioning systems. Marlink will manage this mandatory process, and full details are available on their website.


Will I be affected?

If you're one of the customers who may be affected, you have probably already been in contact with Inmarsat and/or Marlink, to be instructed on any requred action on your part, as well as any potential impact. If you're unsure of your status, please contact Inmarsat or Marlink directly and they will be able to help you.



  • More secure flow of data
  • Simplified and optimised network process
  • Improved accuracy and speed of position tracking

How you may be affected:

  • The new satellite position will mean a change in coverage for a small number of users
  • As a result, some users will need to follow a few simple steps to reconfigure their affected terminals
  • Users should be prepared to reprogramme affected terminals if necessary
  • There are thousands of poll commands expected to be sent following the migration, which will be queued and possibly delayed as a result
  • Extremely old hardware may not be compatible; for example, in cases where the manufacturer is no longer operational


The potential impact of this change is unknown at present; however it is considered to be minimal, and a smooth transition will go unnoticed by the vast majority of users.

If you have any questions or concerns please don't hesitate to contact Marlink, and they will be happy to answer any questions you may have. And as always, you are welcome to contact Pole Star Customer Support if you have any questions regarding your Pole Star account or services.