LEO, MEO, and GEO, Oh My! Modern Satellite Connectivity, Explained

By Graeme Scott, VP of Advanced Networks and Mobility, Telarus

Have you heard the news? Telarus technology advisors now have access to Starlink through our supplier partner MetTel, and partners of Peplink routers. The Starlink offering is internet connectivity via satellite. Satellite is an important addition to any tech advisor’s portfolio as it provides connections for hard-to-reach or remote locations while offering a level of redundancy and resiliency not available with terrestrial circuits alone. As a segment leader in the satellite space, Starlink adds another impressive option for connectivity to the Telarus portfolio. In this blog, we’ll explore the different satellite options available to you, and tips for determining which is best for your clients’ needs.

Satellite Constellation Basics

There are three main types of satellites, or satellite constellations:

1) LEO, or Low Earth Orbit

2) MEO, or Medium Earth Orbit

3) GEO, or Geostationary Earth Orbit (aka geosynchronous)

As the names would suggest, the types differ primarily based on their proximity to Earth.

LEO satellites (Starlink) are positioned at altitudes ranging from approximately 160 to 2,000 miles (257 to 3,220 kilometers) above the Earth’s surface. These satellites have a relatively short orbital period, completing one revolution around the Earth in approximately 90 to 120 minutes.

MEO satellites (GPS) orbit at altitudes between 2,000 and 22,236 miles (3,220 to 35,786 kilometers). The orbital period for MEO satellites is longer than LEO, typically ranging from a few hours to half a day.

GEO satellites (Viasat, DirectTV, Dish) are positioned at an altitude of approximately 22,236 miles (35,786 kilometers) directly above the equator. Unlike LEO and MEO satellites, GEO satellites have an orbital period matching the Earth’s rotation, which is roughly 24 hours. That means that relative to any position on Earth, a GEO satellite will be in exactly the same place. The satellite moves with us as we orbit the sun.

LEO, and even a MEO satellite is going to require a constellation, or a grouping of several satellites to effectively cover the earth, giving GEO an advantage for their operators in terms of scale. To illustrate, Starlink has over 5,500 currently in orbit, with plans for up to 12,000 and beyond. On the other hand, DirectTV and Viasat, both GEO satellites, can cover the entire North American landscape with just a single satellite.

The diagram below shows us the relative orbits of each constellation:

So why does the orbit matter? The proximity and relation to earth give advantages and disadvantages to each of these orbits. A couple of things to consider are latency and stability, or consistency of the connection. The further the signal needs to travel from Earth, the higher the latency. For LEO satellites, the average latency is between 20 and 50 milliseconds. Any gamers out there will balk at a 50ms latency, but this is very comparable to most terrestrial, or land-based networks where we see the average cable connection in the 20-40ms range, and fiber somewhere between 10-30ms. When we move all the way out to our GEO satellite, 22,000 miles away, that latency jumps up significantly to 500 – 700ms, roughly 10x what we see from LEO. It is quite amazing that despite the distance traveled by that signal, it is still sub 1 second. For those of you MEO fans out there, MEO falls somewhere between 30-120ms, with some outliers on either end, based on their orbit.

Since LEO and even MEO constellations require several thousand satellites to cover a given area, it stands to reason we would potentially sacrifice some consistency of signal, add more points of failure, and some potential gaps in coverage.  In this respect, GEO satellite is going to provide wider coverage and a more consistent signal.

Another piece of information relevant to satellite types and their orbit is satellite spectrum. All forms of wireless communication use electromagnetic waves to transmit information, and satellite is no exception. The frequency of these electromagnetic (EM) waves is measured in Hertz (Hz). 1 Hz is equal to one cycle of the wave. Thus, the higher the frequency, the more Hz. All satellites operate in a particular range or “bands” of the EM spectrum. Simply put, more Hz means more information that can be carried. Most LEO satellites, including Starlink, and high-capacity GEO satellites, like Viasat, use the Ka-band spectrum, which allows for two-way transmission. Starlink also utilizes some X and V Band.  Direct TV and other satellite TV operators use the lower frequency C or Ku-band. Ku Band is ideal for broadcast-type transmissions, where data is only flowing in one direction. Although capacity increases as you increase the frequency, so too does the impact of interference. Things like weather can greatly impact the transmission of information. This is one of the main reasons why an external antenna, or terminal and “line of sight” is required for most satellite installations. This can mitigate the impact of weather and ensure that negative effects are mostly short-lived.

Key Considerations for Choosing What’s Best for Your Clients

So, now that we have learned the basics, let’s explore which satellite option you should recommend for your clients and why.

Installation Site

The installation pertains to the actual physical environment where the equipment is installed. For satellites, given our main source of connectivity is located in the sky above, it stands to reason we need to have a view of the sky. This is the concept of “line of sight” referenced above. Ideally, the view from the ground is unobstructed. From there we need the standard requirements of power and a temperature-controlled environment for the modem and indoor equipment. A professional install will ensure everything you need is in place.

Latency

Next, we look at the type of applications that will be running over the connection.  Are they sensitive to latency? If the answer is yes, LEO satellites, like Starlink, would likely be the preferred option. LEO satellites are commonly used for Earth observation, scientific research, and satellite constellations for global communication.  In a scenario where we need a little of both, the MEO orbit allows for a balance between coverage and latency. This makes MEO satellites the preferred choice for navigation systems like the Global Positioning System (GPS).

Consistency

Finally, is stability, or consistency of the connection the most important factor? If so, a GEO connection might be preferred as they are best where we need stable coverage over a fixed area. We commonly see GEO used for communication, broadcasting, and weather monitoring due to constant visibility. In this same vein, it has been the medium of choice for the airline industry, their inflight entertainment, and WIFI. Direct TV and Dish Satellites are also part of a GEO constellation as the high orbit gives them a massive amount of coverage both here in the US and around the world.

To summarize, this chart shows us some of the key differences and use cases for each type of satellite:

Final Thoughts

Satellite internet is a powerful tool in the arsenal of any savvy tech advisor. Knowing how best to utilize this tool can help ensure your customers have the best solutions possible for their network. The Telarus Advanced Solution Team, along with our sales engineers are here to help you dive deeper into these amazing connectivity services.