Three satellite types are critical to worldwide connectivity—LEO, GEO and MEO satellites.
The most important distinction between each satellite type is its orbital altitude or distance from Earth’s surface as it rotates the planet. However, each satellite type is distinct and serves different purposes. Therefore, connectivity experts must understand how each satellite type works in tandem with the others.
In this guide, we’re breaking down each type of satellite, the critical differences between them and how all three types work together to form a vast global network. Today’s communications technologies rely on all three types to provide consistent, high-quality coverage to consumers worldwide.
What are LEO, GEO and MEO Satellites?
While there are a few other types of satellites, three main types currently dominate the sky and bolster worldwide communications networks:
- Low Earth orbit (LEO) satellites
- Medium Earth orbit (MEO) satellites
- Geostationary equatorial orbit (GEO) satellites
Consumers are likely most familiar with LEO satellites. For example, SpaceX is currently using LEO satellites to create its Starlink network.
But the most versatile, comprehensive communications networks combine all three types. So, let’s explore the specific role of each.
Low Earth Orbit (LEO) satellites orbit the planet relatively close to the surface, typically between 160 and 1,000 km/99 and 621 miles above the Earth.
It’s hard to establish a frame of reference for this distance if, like most people, you haven’t traveled to space. By comparison:
- Most commercial flights top out at 12 km/7.5 miles.
- The troposphere (the lowest-altitude atmospheric layer) only extends to 25 km/16 miles.
- The peak of Mt. Everest scrapes the sky at 8.8 km/5.5 miles.
So, while LEO satellites feature the lowest orbital altitudes of all three satellite types, they’re still significantly higher than any altitude most humans typically encounter. For example, the International Space Station (ISS) is a LEO satellite that orbits at 420 km/261 miles above Earth.
One of the most common applications for LEO satellites is imaging, as a relatively close orbit allows satellites to collect high-resolution images. But, for telecommunications purposes, using LEOs can be complicated:
- Since they orbit close to Earth, they can only cover small areas at one time.
- Providers must use many LEO satellites to create consistent service coverage.
- Satellite signals must be tracked by ground antennas, which are typically stationary.
Geostationary equatorial orbit (GEO) satellites are a type of geosynchronous orbit (GSO) satellite. GSOs take one day to complete one orbit, so they always return to the same point in the sky after one day. GEOs, however, are carefully positioned to remain “stationary” over one point in the sky at all times.
GEO satellites typically orbit the Earth at around 35,780 km/22,233 miles from the surface.
The two most common applications for GEO satellites are:
- Weather monitoring
To transmit information, satellites must be visible to ground antennas. This is why GEOs are commonly used in telecommunications—they’re always within view of a stationary antenna on the ground. But they also cover large areas since they orbit further away from Earth than LEO or MEO satellites, providing optimal coverage for communications networks.
To see (or connect with) the entire planet at one time, communications providers only need a few GEO satellites. However, achieving the same coverage with LEO satellites requires significantly more devices in orbit to maintain constant contact with ground antennas and cover enough area to create a reliable network.
Medium Earth orbit (MEO) satellites can orbit at any altitude between LEO and GEO range—MEO altitudes comprise a wide range.
Like LEO satellites, MEOs can take any orbital path around Earth; GEO satellites, however, must maintain a consistent path to achieve constant contact with a ground antenna.
MEO satellites are particularly useful for navigational purposes:
- They can cover relatively large areas.
- They’re easily networked with other satellites to achieve higher coverage.
- They can take a variety of different routes around Earth.
The European Galileo System, the Global Positioning System (GPS) and other Global Navigation Satellite Systems (GNSS) rely upon MEO satellites for tracking moving aircraft to sending directions to your smartphone. But networking is critical—it isn’t uncommon for navigational networks to use more than twenty satellites to send and receive data.
And, like LEO satellites, MEO satellites aren’t always the most practical solution for global communications networks. They move in various orbits, so it can be challenging to maintain visual contact with stationary ground antennas.
Differences Between LEO, GEO and MEO
There are a few important distinctions to remember about LEO, GEO and MEO satellites:
- Altitude – Each type of satellite sails through the sky at a different distance from the Earth’s surface. Altitude choice depends on satellite application and other factors (like the cost of transporting a satellite into orbit).
- Scope – LEO, GEO and MEO satellites all serve slightly different purposes. While they all send and receive signals from ground antennas (and other satellites), the information they transmit varies between satellite types.
- Network size – Depending on the application, LEO, GEO and MEO satellites must be networked using different quantities of individual satellites. For instance, to create a comprehensive global network, LEO satellite operators must use significantly more devices than GEO satellite providers to achieve the same coverage.
Another important consideration for satellites is logistics. It takes significantly more resources and time to place a GEO satellite (in a high orbit) than it does to place a LEO satellite. But, if you need full global coverage from a satellite network, the quantity of LEO satellites could pose logistical challenges.
How All 3 Satellite Types Work Together
The most robust communications networks use a combination of LEO, GEO and MEO satellites to achieve full global coverage at all times:
- GEO satellites can maintain constant contact with ground antennas, offering consistent data transmission. Since they can cover large areas at one time, only a few are needed to create a sizable coverage area.
- LEO satellites can fill in the gaps in GEO networks or provide redundancy. They can also supply telecommunications devices with images or serve as the first stop along a signal’s global journey.
- MEO satellites are versatile; they offer redundancy, additional coverage and extra features like navigational data.
However, telecommunications networks aren’t powered by satellite transmissions alone. Instead, providers achieve optimal, reliable coverage by combining the power of non-terrestrial networks (like satellite systems) with terrestrial networks (radio and microwave equipment).
And as more satellites populate the skies and terrestrial technologies continue to advance, telecommunications capabilities will only improve.
SuperGIG™: A Network of Networks with Satellite Compatibility
LEO, GEO and MEO satellites are all critical parts of any substantial satellite communications network. While each satellite type plays a different role in global telecommunications, they form the networks that connect the globe.
While the entire world relies upon a variety of telecommunications infrastructure to stay connected, first responders rely on networks with broad coverage areas and peak reliability.
Enter SuperGIG™ from IP Access International—SuperGIG™ seamlessly blends terrestrial and space-based networks, delivering unparalleled performance and reliability.
SuperGIG™ ensures reliable high-speed communication for public safety and critical enterprise operations by combining cellular and satellite networks.
If off-grid communications are a must for your team, learn more about the future-proof network solution trusted by first responders worldwide.