Ground Mobile Forces (GMF) is the term given to the tactical SATCOM portion of the Joint Service program called TRI-TAC developed by

GTE-Sylvania Sylvania Electric Products Inc. was an American manufacturer of diverse electrical equipment, including at various times radio transceivers, vacuum tubes, semiconductors, and mainframe computers such as MOBIDIC. They were one of the companies inv ...

in the mid-1970s. The Tri-Service Tactical signal system is a tactical

command, control, and communications Command and control (abbr. C2) is a "set of organizational and technical attributes and processes ... hatemploys human, physical, and information resources to solve problems and accomplish missions" to achieve the goals of an organization or en ...

program. It is a joint service effort to develop and field advanced tactical and multichannel switched communications equipment. The program was conceived to achieve interoperability between service

tactical communications Tactical communications are military communications in which information of any kind, especially orders and military intelligence, are conveyed from one command, person, or place to another upon a battlefield, particularly during the conduct of co ...

systems, establish interoperability with strategic communications systems, take advantage of advances in technology, and eliminate duplication in service acquisitions.

Specifications

GMF is configured in a hub-spoke arrangement with the hub terminal being able to ingest four feeds from the outlying spoke terminals. Of the four designated GMF terminals, the AN/TSC-85B and AN/TSC-100A are equipped for point-to-point or hub operations and the AN/TSC-93B and AN/TSC-94A are spoke terminals. The 85B/100A hubs are capable of ingesting up to 48 multiplexed and encrypted channels from a maximum of four spoke terminals simultaneously, but can double that capability with an external multiplexer (96 channels). Each channel is configured for 16 or 32kbit/s, which with overhead translates to 48kbit/s true capacity. The 93B/94A terminals have a capacity of 24 16/32kbit/s multiplexed channels. All of the GMF terminals have external connections for an AN/TSQ-111 Tech Control Facility, field phones, or a IF wideband input, plus are sealed for sustained operations in a chemical/biological/radiological (CBR) environment. GMF communicates via

Super High Frequency Super high frequency (SHF) is the ITU designation for radio frequencies (RF) in the range between 3 and 30 gigahertz (GHz). This band of frequencies is also known as the centimetre band or centimetre wave as the wavelengths range from one t ...

(SHF) X-band Defense

Satellite Communication A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

System (DSCS) satellites. The 85B/100A hub terminals typically use a . Quick Reaction Satellite Antenna Group (QRSAG) antenna, while the outlying spoke terminals rely on an

parabolic dish A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated ...

antenna.

Obsolescence

Today, much of the TRI-TAC and GMF equipment is obsolete – its bulky circuit-switched equipment having been replaced in the last decade by fly-away

quad-band In telecommunications, a multi-band device (including (2) dual-band, (3) tri-band, (4) quad-band and (5) penta-band devices) is a communication device (especially a mobile phone) that supports multiple radio frequency bands. All devices which ha ...

systems containing compact IP-based routers, switches, and encryption equipment. There are, however, a number of GMF terminals still supporting active forces in the extreme operating conditions of Iraq and Afghanistan.

Specifications

Obsolescence

References

Further reading