Military Satellite Communications (Mil SATCOM) technologies perform an essential role in modern military tactical communications. Field-proven Mil SATCOM solutions are deployed across a broad range of defense applications including military aircraft, vessels, vehicles and portable terminals.
Introduction to Military SATCOM
Satellite Communications (SATCOM) are used for the movement of voice, data and imagery traffic. SATCOM tends to be employed when communications between points A and B eclipse a Line-of-Sight (LOS) range. In contrast, Very/Ultra High Frequency (V/UHF) radios must have an unobstructed LOS range to communicate. SATCOM may also be used when distances between two V/UHF radios eclipse ranges achievable with their V/UHF networks. As a result, SATCOM is employed chiefly for long-range communications at intercontinental distances. Likewise, it may be used when natural or artificial obstacles prevent a LOS range between two V/UHF radios.
Two hypothetical military examples illustrate this: A dismounted special forces team is on a counter-insurgency mission. The team uses Mil SATCOM to communicate with their headquarters thousands of kilometers away in their home country. Similarly, two military vehicles may be separated from each other by a mountain range impeding their LOS V/UHF radios. SATCOM will let these vehicles bypass the mountain range by bouncing their communications traffic across a satellite. SATCOM is routinely used by dismounted troops, vehicles, aircraft, warships and submarines, along with fixed or deployed headquarters, bases and installations.
Adoption of Military Satellite Communication
Use gathered momentum for the military and civilian worlds alike in the late 1950s. The US Advanced Research Military satellite communications Projects Agency embarked on Project SCORE in 1958. An acronym for Signal Communications by Orbiting Relay Equipment, the SCORE satellite was launched on 12th December. It could receive, store and retransmit messages using radio transmissions.
As of 2021, there are almost 100 satellites in orbit used solely for military communications. Militaries also often share government-owned satellites for communications. Some armed forces without access to sovereign communications satellites may lease services using private-sector spacecraft. Militaries with access to sovereign communications satellites may lease additional services from private sector providers.
MIL SATCOM Architecture
Military Satellite Communications (MILSATCOM) provision includes four elements. Firstly, there are the satellites. These are served by fixed or mobile SATCOM terminals furnishing troops, platforms and bases. Communications may also occur via a teleport, a large ground station where traffic is sent and received. Also included in the architecture is the infrastructure supporting the satellites and terminals. This includes installations from where the satellites are controlled and maintained.
SATCOM Frequency Bands
The International Telecommunications Union (ITU), the United Nations agency which is the global custodian of the radio spectrum, reserves specific parts of the radio spectrum for satellite communications. These include sections within the V/UHF, L, C, S, X, Ku and Ka wavebands.
The reason for this plethora of frequencies is because each band has its own strengths and weaknesses. Higher frequency bands like Ku-band and Ka-band are more prone to atmospheric water vapor interference. However, Ku- and Ka-band terminals use small antennas and are more appropriate for SATCOM on-the-move applications and space-constrained platforms. Meanwhile, lower frequency bands like L-band are less susceptible to meteorological interference but use comparatively large antennas. As such, L-band SATCOM may be more appropriate for static applications or large platforms like warships.