Why is satellite communications necessary?

Why is satellite communications necessary?

Millions of people worldwide rely on satellite communications to supply cell phone, radio, television, broadband, and military applications, with over 3,000 communication satellites in numerous orbits at present.

Satellite communication is the worldwide transmission and relaying of information from one location to another via artificial satellites that have been put into Earth's orbit.

It's critical to comprehend the functions of satellite companies and the use cases for satellite communications before delving into the inner workings of satellite communications.

Governments, organizations, businesses, and eventually individuals can convey information via satellite communication thanks to the infrastructure, technology, and solutions provided by satellite firms like Inmarsat.

By providing voice and data communication services in locations where terrestrial cellular and broadband connectivity is unavailable or network coverage is spotty, satellite communications have increased the resilience of terrestrial communications. Examples of these locations include across oceans, at altitudes of up to 35,000 feet, and in remote areas of the earth.

Every day, satellite communication services are utilized, such as:


Radio and television broadcasting
Fast wireless internet and mobile broadband
GPS (Global Positioning System) navigation

Satellite communications is paving the way for a more connected society with limitless opportunities, including autonomous transportation, crop monitoring, unmanned aerial vehicles (UAVs), and sustainability initiatives.

How do communications via satellite operate?

Satellite communications transfer and relay information using microwaves from one location on Earth to another by utilizing a combination of ground stations and orbiting satellites above the planet.

The procedure consists of three steps:

Transponder Uplink Downlink
Consider live television as an illustration. Through its user terminal, a broadcaster will send out (or transmit) a signal to a certain satellite. This is known as an "uplink."

After the signal is received by the orbiting satellite, onboard amplifiers modify the frequency and intensify the signal before returning it to one or more specified Earth stations on Earth. The "transponder" step is another name for this.

Ultimately, these transmitters send out one or more signals to ground station(s) back on Earth, distributed throughout the globe.We refer to this as the "downlink."

Satellite Communications In Two Ways

Point-to-point connectivity is made possible by two-way communication satellite networks, which allow data to be sent and received between the same ground stations using the same satellite.

The advent of two-way satellite communication has made it possible to access the internet in places that are inaccessible to traditional fiber lines, such as offshore platforms, inflight Wi-Fi, and isolated locations like the top of Mount Everest or the midst of the Sahara Desert.

Reunion Stations Available On Earth

All satellite communications are sent and received by satellite access stations (SAS), using either flat panels (also known as electronic directed arrays) or dishes (also known as circular reflectors), to complete the satellite network. Information is processed and sent to its intended location here.

Although Earth stations are typically located in fixed locations on the planet, new technical advancements have optimized signal strengths and data transfer capacities. facilitating the transmission and reception of signals while in motion, such as 5G networks, satellite news gathering, in-flight Wi-Fi, and other mobility applications.

For instance, our ground network of satellite access stations is growing at a rapid rate to satisfy the demand for global mobile connectivity in the future as Inmarsat launches more satellites with never-before-seen power and agility. Learn more about our program for the ground network.

Are satellites classified into several types?

Indeed, there are a variety of satellite kinds that fulfill distinct roles for various organizations.

Any specific communication satellite's application or purpose will dictate a number of things, including orbital trajectories and onboard technology and equipment. Furthermore, some satellites orbit much quicker and closer to Earth than others, while some satellites travel in sync with the Earth's rotation (geosynchronous orbit).

Communication satellites can be divided into four groups according to their orbit:
Earth's geostationary orbit (GEO)
Earth orbit in the middle (MEO)
Earth's low orbit (LEO)
An extremely elliptical orbit (HEO)

Earth's geostationary orbit (GEO)

A geostationary satellite will appear to be motionless if you have ever seen one. This is so because their orbital speed matches that of the Earth. Additionally, they are the furthest distance from Earth.

Satellite networks, such Global Xpress (Ka-band), ELERA (L-band), and ORCHESTRA (Inmarsat) networks, aim to service communication markets where huge data is required for technological breakthroughs.

At the moment, Inmarsat is operating in this orbit. We currently own and manage 16 satellites that are situated 35,786 kilometers (22,236 miles) above Earth in geostationary orbit.

Because of their wide coverage area and capacity to focus where and when needed without wasting it over locations that have no need for it, GEO satellites are incredibly efficient or have little demand. Consequently, fewer ground stations are needed than, say, low-Earth orbit satellites.

This is perfect for mobile satellite communications services where dependable and seamless connectivity is critical, like government agencies or the maritime and aviation safety services. Here are some more use-case scenarios for GEO satellites:

crew communication when at sea
Wi-Fi in flight for unmanned aerial vehicles, or UAVs
Sectors involved in disaster relief include utilities, transportation, and agriculture.

Earth orbit in the middle (MEO)

MEO satellites have an orbital period of two to eight hours and orbit at a height of between 2,000 and 35,786 kilometers (1,243 and 22,236 miles) above the surface of the Earth.

MEO constellations provide low-latency, high-bandwidth connectivity to service providers, government agencies, and commercial enterprises, offering new internet options to remote areas where laying fiber is not an option. Traditionally used for the Global Positioning System (GPS) and other navigation applications.

In contrast to LEO and GEO satellites, MEO satellites have the advantage of requiring fewer satellites and having lower latency than GEO satellites.

Earth's low orbit (LEO)

LEO satellites orbit much closer to Earth than GEO satellites, with an orbit time of roughly 90 minutes and a range of about 160 to 2,000 kilometers (99 to 1,243 miles). LEO orbit necessitates a far bigger constellation of satellites than GEO orbit, which only requires three satellites for worldwide coverage.

Compared to other orbit pathways, LEO satellites operate at a much lower altitude
and so have a smaller field of view and minimal latency, which allows them to accurately relay higher volumes of data at greater speeds and with much better signal strengths. They can thus be applied to a variety of tasks, including:
Industry IoT (Internet of Things) Travel and maritime networks tactical and government networks
Emergency assistance and reaction

Communications and portable 5G internet

This has a price, too, as GEO satellites can stay in orbit for more than 15 years, but LEO satellites can only stay in orbit for five to seven years. A complete LEO constellation typically takes two to three years to deploy, and after that, it will need to be replaced, which will add to the rising concerns about space sustainability and space debris.

An extremely elliptical orbit (HEO)

A highly elliptical orbit (HEO) satellite ranges in altitude from roughly 1,000 to 42,000 km above the surface of the Earth, following an elliptical orbit around the planet.

The very elliptical orbit path's oval journey is the cause of this massive altitude range.

The fact that these satellites travel far more quickly near Earth than they do at a distance is a fundamental aspect of HEO. This is due to the fact that the Earth's gravitational pull is stronger at the satellite's perigee (the point of orbit closest to Earth) than it is at apogee (the point farthest from Earth).

It requires two satellites in high-Earth orbit (HEO) to offer uninterrupted communication. Because it is visible for a longer amount of time during its apogee, which occurs above the North Pole, satellites in HEO may therefore offer superior coverage.

GX10A and 10B, two Global Xpress satellite payloads from Inmarsat, are slated to launch into high-Earth orbit (HEO) in 2023. When in operation, they will serve the government, maritime, and aviation sectors and be the first and only mobile broadband payloads in the world specifically designed for the Arctic region north of 60 degrees north.

Bands of frequencies, beams, and power

In satellite communications, the L-band, C-band, S-band, and Ka-band frequencies are most frequently employed.
The amount of power that can be used to send or receive a signal must be balanced against the extent of the geographic area in which it can be sent or received.

A range of "beam" types are supported by modern satellites, enabling the satellite to direct its power at different intensities to different areas.


Many radars and GPS systems employ L-band frequencies, which are used in the
electromagnetic spectrum between 1-2 GHz. L-band is unsuitable for streaming applications such as speech, video, and high-speed broadband access due to its low bandwidth and low frequency range. However, it is ideal for uses like asset tracking, fleet management, Internet of Things (IoT), and aviation and maritime safety services.

Our vital Global Maritime Distress Safety System (GMDSS) Fleet Safety service and the International Civil Aviation Organization (ICAO)-approved SwiftBroadband Safety service are provided by Inmarsat's 99.9% dependable voice and data ELERA network, which is operated in the L-band.


Radar and satellite communication both employ S-band frequencies, which run between two and four gigahertz. For the space, aviation, and maritime industries, S-band is crucial.

In June 2017, Inmarsat launched S EAN (European Aviation Network), an S-band satellite for the European Aviation Network. In order to give travelers on airplanes throughout Europe a smooth Wi-Fi experience, it was the first dedicated aviation connection solution to integrate satellite and terrestrial networks.


The electromagnetic spectrum 4–8 GHz frequency is where C-band works.
C-band satellites, whose antennas can reach lengths of 1.8 to 2.4 meters, transmit a direct, end-to-end signal. They are mostly utilized for satellite communications, full-time satellite TV networks, and raw satellite feeds, which come in handy in regions affected by severe weather conditions such as heavy rain.

Ka-Band Frequency

Ka-band, which operates in the electromagnetic spectrum between 27 and 40 GHz, is mostly used for high-bandwidth satellite internet.
Applications that require more bandwidth, like live streaming, video conferencing, high-speed internet for services like in-flight Wi-Fi, and multimedia apps, are supported by this higher power frequency. Additionally, providing satellite internet in rural and residential areas of the world is made simpler by this frequency.