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INMARSAT

The Navy INMARSAT program has been in existence since 1991. At that time, a decision was made, based on the lessons learned from Desert Storm, to equip all Navy ships with INMARSAT in order to provide the additional satellite connectivity for: - Civil Coordination - NEO Operations - Augmentation of military assets - Administrative, logistics, mission support traffic - Interoperability with national and international merchant shipping - Coordination of search and rescue operations -Increased ship to shore direct dial telephone access to support CJTF operations.

Lessons learned from Desert Storm documented the necessity of an alternate commercial communications service for logistics and operational support requirements to reduce the saturation of communications on the military tactical satellites. ASD(C3I) in a letter of 8 Nov 1993, directed the use of commercial satellite (COMMERSAT) to augment current and future MILSATCOM systems. This will relieve the congestion on military tactical satellite communications systems while enhancing the overall Navy tactical communications capacity and reduce the competition with tactical data on the limited tactical satellite assets. The COMMERSAT program will use commercial off-the-shelf (COTS)/non-developmental item (NDI) equipment, software, and service with minimal adaptation for the naval environment. Variants of the commercially available INMARSAT terminals will be procured in the next few years. The various types are required to satisfy different requirements on flagships, aircraft carriers, amphib ships and smaller ships. There will also be INMARSAT "B" upgrade mod kits to modify some of the earlier "A" versions. The FY96 procurements included INMARSAT terminals and commercial C and Ku wide band SATCOM terminals in support of Challenge Athena demonstration and shipboard television receive terminals. FY98 and FY99 funds will continue procurement of C and Ku wide band SATCOM Terminals, TV at Sea, ancillary hardware such as Automated Digital Multiplexing System (ADMS) Video Information Exchange Subsystem (VIXS), Automated Network Control Center (ANCC), Global network Initiative, INMARSAT terminals, production support and personal communications systems which are miniaturized portable satellite radios.

The Navy INMARSAT program completed outfitting all of its large ships (ARS class and above) with INMARSAT A systems by 1995. In 1996, Navy commenced implementation of INMARSAT M systems in its smaller ship classes (i.e. MCM/MHC/PC) and introduction of the INMARSAT B system to replace the older analog INMARSAT A system.

Navyís INMARSAT B program has been restructured to meet the CINCís requirements for IT-21. The digital INMARSAT B is now required to support wideband and reachback transmission requirements for selected ship classes. As such, INMARSAT B is required to support NIPRNET, SIPRNET, JWICS, and voice requirements in an integrated Battle Group, integrated ARG or split BG/ARG environment on a 24 hour a day continuous basis as opposed to an on-demand/dial-up basis. In order to meet this requirement, INMARSAT B channels must be leased for each ship and each shipís exclusive use. INMARSAT B as installed in FY97 (pre-IT-21) supports an on demand dial up circuit capable of up to 64 kbps data rate and interfaces to the public switched telephone network (PSTN) from the INMARSAT B earth station. As such, connectivity to a Navy communications network is and has not been necessary.

In the IT-21 shipboard configuration the INMARSAT B system must support a full time encrypted 64 kbps channel and must be interfaced into the ADNS architecture for NIPRNET/SIPRNET data dissemination. Similarly ashore, the INMARSAT B 64 kbps channel must be extended to a Navy ADNS point of presence for interface to the SIPRNET/NIPRNET networks. This necessitates additional terrestrial connectivity from the INMARSAT land earth station and the nearest Navy ADNS point of presence-normally a NCTAMS/NCTS.

Modifications afloat are necessary to encrypt/decrypt the INMARSAT B channel, modify the INMARSAT B software to enable use of full time 64 kbps channel service, interface the circuit to ADNS, and multiplex/demultiplex the circuit to allow for simultaneous voice and data. Modifications ashore are necessary to encrypt/decrypt the INMARSAT B channel, interface the circuit from the INMARSAT B earth stations to the Navy ADNS, and multiplex/demultiplex the circuit to allow for simultaneous voice and data.

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http://www.fas.org/spp/military/program/com/inmarsat.htm
Maintained by Robert Sherman
Originally created by John Pike
Updated Thursday, April 13, 2000 8:00:03 AM