Ground Mobile Forces
Encyclopedia
Ground Mobile Forces is the term given to the tactical SATCOM
portion of the Joint Service program called TRI-TAC developed in the mid-1970s. The Tri-Service Tactical signal system is a tactical command, control, and communications
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
systems, establish interoperability with strategic communications systems, take advantage of advances in technology, and eliminate duplication in service acquisitions.
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 chan). 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 70 MHz IF wideband input, plus are sealed for sustained operations in a chemical/biological/radiological (CBR) environment.
GMF communicates via Super High Frequency
(SHF) X-band Defense Satellite Communication
System (DSCS) satellites. The 85B/100A hub terminals typically use a 20 ft. Quick Reaction Satellite Antenna Group (QRSAG) antenna, while the outlying spoke terminals rely on an 8 ft. parabolic dish
antenna.
Today, much of the TRI-TAC and GMF equipment is obsolete – its bulky circuit-switched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 systems containing compact IP-based routers, switches, and encryption equipment. There are, however, a number of GMF terminals still reliably supporting wartime efforts in the extreme operating conditions of Iraq and Afghanistan.
SATCOM
SATCOM or Satcom may refer to:* Short for Satellite Communications and used frequently in the context of VSAT * Communications satellites or comsats...
portion of the Joint Service program called TRI-TAC developed in the mid-1970s. The Tri-Service Tactical signal system is a tactical command, control, and communications
C4ISTAR
In military usage, a number of abbreviations in the format C followed by additional letters are used, based on expanded versions of the abbreviation C2 - command and control.C2I stands for command, control, and intelligence....
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
Tactical communications are communications in which information of any kind, especially orders and decisions, are conveyed from one command, person, or place to another within tactical forces. In modern times, this is usually done by electronic means....
systems, establish interoperability with strategic communications systems, take advantage of advances in technology, and eliminate duplication in service acquisitions.
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 chan). 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 70 MHz IF wideband input, plus are sealed for sustained operations in a chemical/biological/radiological (CBR) environment.
GMF communicates via Super High Frequency
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
(SHF) X-band Defense Satellite Communication
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
System (DSCS) satellites. The 85B/100A hub terminals typically use a 20 ft. Quick Reaction Satellite Antenna Group (QRSAG) antenna, while the outlying spoke terminals rely on an 8 ft. parabolic dish
Parabolic reflector
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis...
antenna.
Today, much of the TRI-TAC and GMF equipment is obsolete – its bulky circuit-switched
Circuit switching
Circuit switching is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the...
equipment having been replaced in the last decade by fly-away quad-band systems containing compact IP-based routers, switches, and encryption equipment. There are, however, a number of GMF terminals still reliably supporting wartime efforts in the extreme operating conditions of Iraq and Afghanistan.