Thrane&Thrane TT-3084A Sailor Fleet77, User Manual

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The Inmarsat Fleet Service Introduction
2
2.2 The Inmarsat Fleet Service
The Inmarsat Fleet service is based on 4 Geo-stationary 3
rd
generation satellites situated above the equator. Geo-
stationary means that the satellites are always located in
the same position, i.e. they rotate at the same speed as
that of the earth. Each satellite covers a certain area
(footprint) and supports a number of powerful spot-beams
making the service available in virtually all ocean regions
on the earth between approximately 70°N and 70°S.
The 4 Geo-Stationary Inmarsat Satellites
The satellites are your connection to the worldwide
networks, and they are managed by the Network Co-
ordination Stations (NCSs), run by Inmarsat. The primary
functions of the NCSs are to constantly keep track of which
terminals are logged on to the system, and assign a free
channel whenever a call is made.
The gateway between the public network and the satellites
are operated by Land Earth Stations (LES). The LES are run
by different operators around the world.
The Fleet services are prepared for operation with the next
generation of Inmarsat satellites (Inm-IV) expected in
2005.
May 2005 5