Intro; LEO vs. GEO
Before we dive into exploring LEO and GEO, let’s briefly discuss what satellite internet is and how it actually works. The bare bones definition of satellite internet is that it is the process of accessing the internet by using radio waves to communicate with satellites orbiting the Earth. Satellite internet is location independent and because it provides global coverage, the connection could be taken anywhere. This form of internet access is a wireless connection that involves three satellite dishes: one at the internet service provider’s hub, one in space, and one attached to your property. In addition to your satellite dish, you will also need a modem, and cables running to and from your dish to your modem.
What is LEO?
LEO, or Low Earth Orbit, is a type of satellite internet service that uses a grid (or constellation) made up of thousands of satellites in orbit close to the Earth. Low Earth Orbit is considered the area in Earth’s orbit near enough to Earth for convenient transportation, communication, observation, and resupply. A LEO satellite is usually placed between 300 miles (500km) and 1,200 miles (2,000km) above the Earth; this lower orbit dramatically reduces the lag that often comes with satellite internet. These devices also have a limited Field of View (or FoV), which is why a high number of them is necessary for complete Earth coverage. Commercial users or enterprises, defense and military personnel, and people who travel abroad or operate in places that are far from cellular coverage make use of the LEO satellite applications.
What is GEO?
GEO is short for Geosynchronous Equatorial Orbit. Also referred to as Geostationary satellites, GEO satellites orbit the Earth at the exact speed the Earth itself rotates, hence the name geostationary. Looking at them from the ground, they appear stationary and unmoving while at a high altitude of about 22,000 miles (35,000 km) above Earth’s surface. Weather forecasting, satellite radio, and television are among the multiple applications for GEO satellites. Also, while a high quantity of LEO satellites is necessary to provide complete Earth coverage due to their lower altitude and limited Field of View, only one GEO satellite is necessary provide coverage over an entire given location thanks to their stationary positions in orbit.
Pros and Cons of LEO
As previously mentioned, Low Earth Orbit satellites are positioned at a significantly lower altitude compared to GEO satellites and therefore they do not require a lot of power for communication signals. The closer proximity allows these satellites to capture images with higher resolution and detail, and more importantly, decreases the amount of time needed for a signal to travel to and from the satellite to the Earth station. Additionally, LEO satellites provide high elevation for polar regions of the Earth which leads to better global coverage, whereas the GEO orbit is located above the equator, which makes it difficult to broadcast near the polar region.
However, because these satellites move so fast across the sky (a LEO satellite takes approximately 90 minutes to circle the Earth), LEO satellites are less useful for tasks such as telecommunication as their speed requires a lot of effort to track from ground stations. Furthermore, the atmospheric effects on these satellites are higher and cause gradual orbital dis-orientation. Because of this, regular maintenance of these satellites is required to keep them on track in the LEO orbit.
Pros and Cons of GEO
Geosynchronous Equatorial Orbit satellites cover a much broader range of Earth compared to LEO satellites; as little as three equally spaced GEO satellites can provide near global coverage. Thanks to their geostationary positioning in the sky, GEO satellites are visible for 24 hours continuously from a single fixed location on the Earth, and therefore ground station tracking is not required for them as it is for LEO satellites. These satellites are also ideal for broadcasting and multi-point distribution applications.
Conversely, a downside to GEO satellites is that their signals require considerable time to travel from Earth to satellite and vice versa, and because of the longer transmission distance, the received signals can be very weak. To counterbalance this issue, a better LNA (Low Noise Amplifier) is required as well as advanced signal processing algorithms in the satellite modem, which increases the cost of the ground station equipment.
Conclusion
Let’s review how satellite internet works! Satellite internet is the process of accessing the internet with the help of communication satellites, the most common types of these satellites being either LEO (Low Earth Orbit) or GEO (Geosynchronous Equatorial Orbit). It is the ideal form of internet connection for areas where quality of access is unreliable, or poor places where terrestrial internet access is unavailable. It’s a five-part relay system involving an internet-ready device, a modem/router, a satellite dish, a satellite in space, and network operations centers.
LEO is a type of satellite internet service that uses a grid (or constellation) made up of thousands of satellites in close orbit to Earth. A high number of these satellites is required because of how fast they travel around the planet, whereas GEO satellites move at the same speed as Earth (therefore they appear stationary in the sky) so only a few are necessary for near global coverage.
