3
Chapter 2
Introduction
2
The Inmarsat Fleet Service
2.1
Overview
2.1.1
The Inmarsat Fleet service is based on 4 Geostationary 3rd generation
satellites situated above the equator, but can also operate on the new 4th
generation satellites. Geostationary 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 Geostationary Inmarsat Satellites
The satellites are your connection to the worldwide networks, and they are
managed by the Network Coordination 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 is operated by
Land Earth Stations (LES). The LESs are run by different operators around the
world.
