Satellite Communication Services – Overview

Satellite communication services refer to transmission/ reception of data, voice or video signal via communication satellite in Earth’s orbit. These services provide global coverage and are widely used for various purposes, including telephony, television broadcasting, internet connectivity, military applications, and remote sensing.

What is a Satellite?

Satellite refers as any object that rotates around another object in space. Some satellites are natural while others are man-made or artificial. One example of a natural satellite is the moon which revolves around the Earth.

In today’s generation, the term satellite is referred to artificial objects that rotates on the earth. Similar to their natural counterparts, these artificial satellites orbits round the planet and they are intentionally placed into orbit.

What is Satellite Communication?

Satellite communication refers to the transmission and reception of information, such as data, voice, and video signals, using artificial satellites orbiting the Earth. It is a method of long-distance communication that provides wide coverage and enables global connectivity.

In other words, it is a way of transferring signals through an artificial satellite to multiple locations on the Earth. Satellite communication creates a communication channel between a transmitter source and a receiver at various locations on the earth. Communication satellites are used in Televisions, radios, internet, telephone and military applications.

Spring up of Satellite Communication

The world’s first artificial satellite is Sputnik 1 which was placed into the orbit by the Soviet Union in the year 1957, 4^th October. This Sputnik was launched towards the major exploration of space and development of rocket.

Having said that, this was not placed in the orbit to send the data from one point on earth to another. In fact, Pioneer 1 was the first satellite communication to communicate which was a purpose to lunar probe.

Applications of Satellite Communication Services

Here, are the few applications:

Satellite Phones

They are first and most important use of communication satellites. The telephone network that is public switched carries telephone calls from landline phones to an earth station from where they are transmitted to geostationary satellite.

There are other land use of satellite phones which includes ships and other equipment at sea, backups for hospitals, military and recreation etc. The satellite phones connect directly to constellation of either the geostationary or low-earth-orbit satellites. Hence, the calls get forwarded to a satellite teleport connected to the public switched telephone network.

Satellite Television

Satellite television offers a wide range of channels and services. In many remote areas, it is the only television available which do not have cable television service. It is when the television program is delivered to the viewers by communicating from communication satellite revolving the earth directly to the viewer’s location.

The signals for this satellite is received by an outdoor parabolic antenna which is referred to satellite dish and a low-noise block downconverter. The satellite receiver which is either an set-top box or a in-built television tuner decodes the required television programme for watching on television set. Satellite television usage now has become with less buyers as people prefer to watch internet based streaming television and also due to chord cutting trend.

Satellite Radio

A satellite radio is digital radio signal which is communicated by a communication satellite and this covers a wide geographical range than terrestrial radio signals. In the countries like US, satellite radio provides audio broadcast services. Listeners can travel anywhere across the continent and tune into the same audio programming using the mobile services like SiriusXM and World space.

The antenna should have a clear view to the satellites in all the above-mentioned instances. In case of tall buildings, bridges, parking garages which has the known signals, the repeaters can be used to make the signals available to all the listeners.

Radio Satellite

Radio satellites seems to be not so professional. These radio operators make use of unprofessional satellites. These satellites mostly function as spaceborne repeaters. They are usually used by unprofessional who are equipped with ultra-high frequency and very-high frequency radio equipment with highly directional antennas.

Due to their launching costs, most of the unprofessional satellites were launched in low-earth orbit and they are particularly designed to deal with few contacts at a given specific time.

Satellite Internet

Satellite internet refers to internet access that is possible through communication satellites. After the year 1990, in order to connect to the internet broadband data connections, the satellite communication technology was utilized. This technology was most useful in the remote areas who cannot avail broadband connection.

Satellite for Military

Military communication applications like Global command and control systems use satellite communications. The satellite that were used are – MILSTAR, the DSCS, the FLTSATCOM of US, NATO satellites, UK satellites and finally the former satellites of Soviet Union. GSAT-7 is India’s first military communication satellite.

Satellite Communication in India

In the geo-stational orbit, the Indian National Satellite (INSAT) is one of the largest domestic communication systems. In INSAT, there are more than 200 transponders and each of them are used for various purposes like telecommunications, weather forecasting, television broadcasting, disaster warning, search and rescue operations and satellite newsgathering.

To name a few, below are the different types of satellite communications along with their applications-

Types of Satellite Services

Following are the ways of Satellite Communication Link Service:-

One-way Satellite Communication Link Service

Here, the information will be transferred from one earth station to one or more earth stations via satellite i.e., it connects point to point connectivity and one point to multi point connectivity.

Below mentioned are some of the one-way satellite communication link services –

• Radio, tv and internet services are broadcasting satellite services.
• Telemetry, Tracking and Commanding services are some of the space operations.
• Position location service is the radio determination satellite.

Two-way Satellite communication Link Services

Here, the information can be exchanged between any two earth stations via satellite i.e., it provides point to point connectivity only.

 Below mentioned are some of the one-way satellite communication link services –

Telecommunication Services

Satellites provide telecommunication services for long-distance communication, including voice calls, video conferencing, and data transmission. These services enable global connectivity and communication between individuals, businesses, and organizations.

Broadcasting Services

Satellites play a vital role in broadcasting television and radio signals. Direct-to-Home (DTH) television services, satellite radio, and satellite television distribution are examples of broadcasting services delivered through satellites.

Internet Connectivity Services

Satellite internet services provide internet access to areas where terrestrial infrastructure is limited or unavailable. These services utilize satellite links to deliver internet connectivity to remote and underserved regions.

Navigation Services

Satellite-based navigation systems, such as GPS (Global Positioning System), offer accurate positioning, navigation, and timing information. GPS satellites transmit signals that allow GPS receivers to determine precise locations and assist in navigation.

Remote Sensing Services

Satellites equipped with remote sensing instruments capture images and data about Earth’s surface and atmosphere. These services support applications such as weather monitoring, environmental analysis, and natural resource management.

Military and Defense Services

Satellites play a crucial role in military and defense operations. They provide secure communication channels, surveillance capabilities, reconnaissance data, and intelligence gathering for military applications.

Weather and Climate Services

Satellites equipped with weather monitoring instruments gather data used in weather forecasting and climate research. These services help track weather patterns, monitor atmospheric conditions, and provide early warnings for severe weather events.

Earth Observation Services

Satellites with imaging sensors capture detailed images of Earth’s surface. There is use of Earth observation services for applications such as mapping, urban planning, agriculture, environmental monitoring, and disaster management.

Mobile Satellite Services

These services enable communication via mobile devices in areas with limited or no terrestrial network coverage. Mobile satellite services are useful for maritime communication, remote regions, and emergency situations.

Scientific Research and Exploration

Satellites support scientific research and exploration missions. They enable the study of space, astronomy, celestial bodies, and other scientific disciplines, providing valuable data for scientific advancements.

Advantages and Disadvantages of Satellite Communications

Below mentioned are some of the advantages and disadvantages of satellite communications:

Working of Satellite Communication

The working of satellite communication involves a series of steps that enable the transmission and reception of signals between ground stations and satellites. Here is a  description of the working principles:

Signal Transmission

The process begins with a ground station sending signals to a satellite. The ground station consists of an antenna, which transmits the signals at a specific frequency toward the satellite. The signals contain information such as data, voice, or video.

Uplink Reception

The satellite receives the transmitted signals through its own antenna, known as the uplink. Basically, the design of the uplink antenna is to capture the incoming signals from the ground station.

Signal Processing

Once the signals reach the satellite, they are processed and amplified by specialized equipment called transponders. Transponders receive signals on one frequency (uplink frequency), amplify them, and retransmit them on another frequency (downlink frequency).

Signal Re-Transmission

After processing and amplification, the satellite retransmits the signals back to Earth. The signals are transmitted through the satellite’s downlink antenna, which broadcasts them over a wide coverage area.

Downlink Reception

Ground stations equipped with antennas that are designed to receive signals at the downlink frequency capture the signals transmitted by the satellite.

Signal Processing and Distribution

Once the signals reach the ground station, they undergo further processing to extract the original information. The ground station may have various equipment and systems to decode, distribute, and utilize the received signals according to their intended purpose.

Communication with End Users

The signals received at the ground station can be further distributed to end users via wired or wireless networks. These users may include individuals, businesses, or other organizations that require communication, data, or media services.

Note: Satellite communication often involves two-way communication, where signals are transmitted in both directions. This allows for interactive communication, such as telephony or video conferencing, where information flows between the ground station and the end user.

In some cases, a network of multiple satellites and ground stations is employed to provide broader coverage and redundancy. This network allows for seamless communication handover as satellites move across different regions and ground stations transfer signals between each other.

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