Are you hearing more about Low-Earth Orbit (LEO) satellites and wondering:
1) What are they?
2) How do they differ from Geostationary Earth Orbit (GEO) satellites?
3) Could they help with my connectivity issues?
In this article, we discuss and explain the key attributes of LEO and GEO satellites and how they compare to one another. Watch our video or continue reading below:
Low-Earth Orbit (LEO)
Low-Earth Orbit satellites are one of the latest innovations within the satellite industry, offering signal coverage to those currently connected and to the 4 billion that have been unconnected for the past 50 years. It is obvious from the name that these satellites are situated lower in the Earth’s orbit (in fact they are in a lower orbit than any other satellite), but let’s dive a little deeper into the detail of why LEO satellites are growing in topic discussions, popularity and why you may even consider integrating them into your connectivity solutions.
How are LEO Satellites contending with the traditional types?
LEO satellites have a magnitude of advantages over GEO due to their proximity to the earth. These satellites are between 800 – 1600km above the surface, which is around 22 times closer than GEO. But why is being closer to the surface of the earth a good thing?
First and foremost, the proximity of the satellites allows them to produce high speed and low latency communications (30 to 50ms), demonstrating just a 0.05-second delay on average. This ensures a more stable connection with less interference as communications have a shorter distance to travel, making them more suited to IoT applications than GEO. Additionally, the low-earth orbit has an impact on the cost and time of launching the satellites, which is substantially lower than others due to the shorter flight path. The reduction in cost is also a result of the small stature of the satellite making it both cheaper and faster to manufacture in comparison.
LEO satellites can offer coverage to areas that are too far north or south of the equator. Due to the smaller size of LEO satellites, constellations work together to ensure complete coverage of the earth, accessing areas such as the pacific or polar regions not reachable by current GEO satellites. LEO satellites not only provide more coverage, but they also orbit the earth much faster, completing a full rotation every 93 minutes (around 16 cycles per day). Due to the pace of the satellites, they can only be viewed for a few minutes, and therefore, the information within each satellite must be handed off to the next to ensure the stability of the connection to its users on earth.
Use Cases of LEO Satellite Internet:
LEO opens up opportunities to extend connectivity to difficult to reach areas, making it perfect for markets including:
- Aviation – commercial and business flights
- Maritime – shipping, commercial fishing
- Search and rescue operations
- Utilities – including wind farms and hydro plants
- Offshore – oil rigs
Challenges of LEO Satellites:
- As the satellites orbit the earth so often in one day, technicians may only have up to 20 minutes to ensure the satellite is in good health
- Many satellites are needed to cover one area due to their small stature
- Ground stations are complex due to the multitude of LEO satellites passing through
- Satellites have just a 5–8-year life span
Geostationary Earth Orbit (GEO)
Geostationary Earth Orbit (GEO) satellites, which have been around for over 50 years, were first launched for communications in NASA’s Syncom III experiment in 1964, providing worldwide television coverage of the Tokyo summer Olympics. Since then, the GEO satellite has been relied on for many daily communications such as the weather reports we watch on TV. However, with constant innovations like LEO satellites, will GEO be relied on as much as they once were?
How do GEO Satellites work
GEO satellites differ in many ways from LEO. Orbiting at around 35,000km (22,000 miles) from the surface of the earth, GEO satellites are said to ‘hover’ in one spot above the equator. Within this very high orbit, the satellite spins at the same pace as the earth, meaning it completes one full rotation at the same time as the earth. This takes an average of 23 hours, 56 minutes, and 4 seconds, making it easier for the receiving dish on the ground. As the satellite remains in one position the antenna does not need to move to track it across the sky.
Unlike LEO, GEO can only offer coverage to a specific area of the earth, this includes anywhere 70 degrees in latitude above or below the earth’s equator. Due to the curvature of the earth, the stationary satellite is unable to reach areas in the north or the south, in particular the polar regions of the earth. This means that up to 4 billion potential users have remained unconnected throughout the years.
The cost and time of manufacturing and launching a satellite into GEO is much greater than LEO satellites. However, due to the size of a GEO satellite, each covers a larger surface, meaning fewer are needed to offer coverage to a specific area, with only 3 satellites required to give complete communication coverage.
Challenges of GEO Satellites:
- They offer coverage to just 42% of the Earth
- Up to 600 millisecond latency in retrieving information
- Most expensive type of satellite to produce
- Satellites have just a 10-year life span
Although LEO and GEO are very much polar opposites in terms of altitude, each aims to offer the same solution – internet access to specific areas around the globe. That being said, the technologies and proximity of LEO satellites can offer a higher speed, lower latency connection to everyone around the globe. Therefore, it is becoming clear that LEO is the future for satellite internet – from maritime to aviation, these satellites are quite simply transformative for global connectivity. To discuss how we can help, please get in touch.