FLEET SATELLITE
COMMUNICATIONS
T h e F l e e t S a t e l l i t e C o m m u n i c a t i o ns
(FLTSATCOM) System provides communications,
via satellites, between designated mobile units and
shore sites. These links provide worldwide coverage
between the latitudes of 70 degrees north and 70
degrees south. Three satellites are currently in use with
a fourth to come online soon: GAPFILLER, LEASAT,
FLTSATCOM, and UHF Follow-on (UFO).
System installations are located on ships,
submarines, mobile vans, aircraft, and shore stations.
Though these installations could operate separately,
integrating the system provides message traffic and
voice communications to all DOD long-range
communications networks. In addition, certain shore
stations provide a back-up capability to other users in
case of an outage of any kind, which maintains net
connectivity.
The Navy SATCOM system consists of
information exchange subsystems that use the
satellites as (1) relays for communications and control,
and (2) quality monitoring subsystems that provide
data required to manage satellite resources. Each
subsystem is structured for specific naval
communications requirements. The following
subsystems make up most of the Navy’s FLTSATCOM
system.
Fleet Satellite Broadcast Subsystem. This is an
expansion of the “Fleet Broadcast,” which has
been the central communications medium for
operating naval units.
Common User Digital Information Exchange
Subsystem (CUDIXS) and Navy Modular
Automated Communications Subsystem
(NAVMACS). These two installations form a
communications network for transmitting
general-service message traffic between ships
and shore installations.
Submarine Satellite Information Exchange
S u b s y s t e m (SSIXS). T h i s s u b s y s t em
compliments other communications links
between SSBN and SSN submarines and shore
terminals.
Secure Voice Subsystem. This is a narrowband
uhf subsystem that links voice communications
between ships and connects with wide-area
shore voice networks.
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Tactical Intelligence Subsystem (TACINTEL).
This subsystem is specifically designed for
special intelligence communications.
Teletypewriter Subsystem. This subsystem is an
extension of terrestrial teletypewriter
transmission networks.
Tactical Data Information Exchange Subsystem
(TADIXS). This is a one-way broadcast of
tactical information from command centers
ashore to afloat units primarily in support of
over-the-horizon targeting (OTH-T).
Officer in Tactical Command Information
Exchange Subsystem (OTCIXS). T h is
subsystem continues to provide inter-and intra-
battle group communications and is now also
designated as the return path for ship-to-shore
OTH-T communications.
Demand Assigned Multiple Access (DAMA)
Subsystem. This subsystem was designed to
multiplex several subsystems, or users, on one
satellite channel, allowing more satellite
circuits to use a single uhf satellite channel.
Control Subsystem. This subsystem is a
communications network that provides status
reporting and management of system assets
The installation of subsystem baseband
equipment and rf terminals aboard ships is driven by
communications traffic levels, type of com-
munications, and mission requirements. For example,
Fleet Broadcast, a common subsystem in naval com-
munications, is received by many different types of
ships. Atypical suite on a large ship may include Fleet
Broadcast, CUDIXS, NAVMACS, Secure Voice,
TADIXS, OTCIXS, Teletypewriter, and TACINTEL
equipment.
Most subsystems have very rigid control and
accountability of message and data-link traffic. All
subsystems have some form of backup mode. Within
the constraints of equipment capability, each
subsystem addresses the unique requirements of the
user and the environment in which the user operates.
On board your ship, you may not use all these systems,
but during your career you will probably come across
all of them. Now that we have identified the satellite
communications subsystems, we need to provide you
