Title: Satellite Infrastructure
Course: 2016FA-MCO-115-401 > Section: Module 5: Communications

Click here for a downloadable version of this document: Satellite Infrastructure

Satellite Infrastructure

A satellite, according to the Merriam-Webster dictionary, is, “an object that moves around a much larger planet” [11]. A communications satellite, sometimes referred to as a comsat, is a man-made device sent into the Earth’s orbit to aid in communications [12].

Satellite communications are useful for television, radio, Internet, voice, and more applications. Each of these applications would require a different amount of bandwidth for transmission, the amount of bandwidth that a satellite can offer depends on the number of transponders it can provide [12].

Communications Satellites are generally made of the following components (or similar):

- The communication payload (Transponders, antenna, switching systems, et cetera)
- Engines (Required to get the satellite into the desired orbit)
- Station keeping tracking and stabilization subsystem (this is the portion that keeps it in the right orbit, keeps its solar panels facing the sun, and keeps its antenna pointed the right way)
- Power subsystem (the solar panel and solar power system and the batteries that store power for situations like solar eclipses)
- Command and control subsystem (this maintains communications with ground control stations)

[12]

Telephones

Telephones were a first use for communication satellites, intercontinental long distance telephone calls were made possible by satellites. The fixed public switch telephone network relays calls from landline phones to earth stations and from there the calls go to geostationary satellites and then the process reverses back to earth station, the public switch network, and then on to the landline phone on another continent. The development of fiber optics has meant more submarine lines were placed between continents allowing for calls to be made without the use of satellite technology. This technology may not be as commonly used as it once was, but it still is a main form of communications for remote areas of the world like Antarctica. It is also still used on boats and ships at sea, in military applications, in airplanes, and as a backup communications method at hospitals and other emergency organizations. Special telephones called satellite phones are available and are designed to be portable and to use communications satellites. There is a satellite teleport that connects satellite phone calls to the public switched network [12].

Television

Satellite television is currently provided in the United States by well-known companies like DirecTV and DISH Network. They often use Direct Broadcast Satellite (DBS). A DBS is a comsat that transmits to small DBS satellite dishes. Fixed Service Satellite (FSS) can also be used, as is the case with DISH Network’s Super Dish antenna system. FSS satellite communications are used for network television and affiliate broadcast feeds, and has applications for distance learning and videoconferencing [12].

Radio

In the United States Sirius XM is the well-known provider of satellite radio to the public. It provides fewer commercials and much more coverage than traditional broadcast radio (coverage is nationwide). There are also amateur radio satellites. These are typically repeaters in orbit around the Earth that are accessed by amateur radio operators with UHF or VHF radio equipment and highly directed antennas [12].

Military

The United States military uses satellite communications for some applications. The military satellites usually operate in UHF, VHF, or SHF (X band) frequencies [12].

Internet Access

Satellite broadband, an Internet connection provided through satellite, works in two steps. First, the computer communicates through a satellite modem to a satellite dish. Then, the dish sends and receives signals from the satellite [14].

Since the 1990s those who live in remote areas have the option of using satellite communications technology to connect to the Internet [12].