Galileo, GPS, and the rest

In this blog we walk you through the different Satellite Positioning Systems: GPS, Galileo, GLONASS, and more.

Table of contents

1. GPS: The Godfather of it all

2. The Rest

3. Galileo

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I recently watched an episode from Netflix’s “History 101” about GPS, and I realized how little I knew about the origins of a technology that so many of us rely on in our everyday lives. I’ve thrown in the word “GPS” a couple of times throughout my blogs but never took a step back and thought about how significant satellite location technology really is. We use it for farming, science, emergency responses, road trips, delivery, and a lot more that I can’t be bothered to list right now.

GPS is one of a few satellite-based navigation systems that we have orbiting our Earth. The latest member of this party is the European Space Agency's (ESA) Galileo. I'd like to talk about why Galileo is important for Europe and location technology. To do that, we’ll need a little crash course on GPS, and how satellite-based navigation came to be.

GPS: The Godfather of it all

When the Soviet Union launched Sputnik 1 into space, two American physicists, William Guier and George Weiffenbach had the idea to monitor the satellite's radio transmissions. The two clever fellas quickly realized that, due to the Doppler effect, they could pinpoint exactly where the satellite was along its orbit. The "History 101" episode explains that William and George’s boss expanded on that idea and reversed the logic. He wanted to find out if they could track the transmission from the satellite at a known trajectory, would that allow them to pinpoint the location of a receiver? Tune in next time to find- yes they could. William, Goerge, and their boss said:

And that's what they did.

The US military loved this discovery. The Navy was using Sonar technology for its targeting system but a satellite-based targeting system had potential to be better because it was invisible to the enemy (the Decepticons). They built a satellite program named Transit, and by the 1960s they had a 6-satellite system operational. Targeting accuracy needed some fine tuning here and there, but navigation via satellite was working. The Decepticons didn’t know what hit them, literally.

Optimus Prime
Is he a Decepticon? No. Is it relevant to the blog? Also no. Does it matter? Again, no.

Fast forward to 1973, Colonel Brad Parkinson had a top-secret meeting with a group of engineers at the Pentagon. He wanted to build a satellite “global positioning system” with 24 satellites orbiting the Earth twice a day, in one of six fixed orbits to achieve 24-7 global coverage. On the surface, a GPS receiver will take signals from at least four available satellites, measuring their distance from each one, and hey presto, you got a precise ground location. Don't let the simplicity of my tone fool you, the brainpower behind this is remarkable. The entire US military had the navigational edge on every front by the late 70s, thanks to GPS.

So how did GPS go from a strictly US military technology to a globally accessible one? That’s due to a tragically sad event. In September 1983, the Soviet Union shot down a Korean Airline passenger plane that entered Soviet airspace, killing 269 innocent people. As you can imagine, this was a diplomatic headache. However, it is thought that the pilots deviated from their pre-planned route, and found themselves in prohibited airspace. With access to GPS, the tragedy could have been avoided. President Ronald Reagan signed an executive order that allowed civilian use of the GPS system for free. As a result, flying and air traffic control became a lot safer, private companies were allowed to produce their own GPS receivers, people started building things that use GPS, and it all became very much part of our daily lives. That’s the condensed version of the 20-minute Netflix episode.

The rest

There’s one thing to remember about GPS, it’s a US-owned technology that emerged in the midst of the Cold War. When President Reagan made it available to the public, the US government decided to provide a separate signal for civilians. That signal was weaker than what the military had. The purpose of this was so that adversaries of the US (the Decepticons) could not capitalize on the technology. This led to “Selective Availability”, which meant the US could flip a switch, and the civilian GPS signal would start going all over the place while the military one worked fine. That still remains the case today, but soon after GPS became fully operational other countries followed suit.

Here's a list of the current satellite navigation systems (excluding Galileo and GPS):

All these systems are built for the regions they cover. Before Galileo, Europe relied on GLONASS and GPS, but that dependency can come at a cost. European highways would descend into utter chaos should the US turn off the civilian signal for whatever reason. Hence, it was inevitable for the ESA to develop its own satellite navigation system for Europe.


“When close isn’t enough, use Galileo”. Talk about a confident tagline, but the ESA can back up the bravado. Galileo’s overarching goal is to provide Europeans with a free and independent satellite navigation system. GPS and GLONASS are non-civilian satellite navigational systems built for the military. On the other hand, Galileo is a civilian-first satellite navigational system.

So, a satellite system for the people. That’s great, but when it comes to accuracy, how does it fare against its competition? ESA aren't bluffing with the tagline. It has an average accuracy of 1m, and can optimally go down to 0.01m. To compare, GPS has an average accuracy of 3.6m. To date, Galileo delivers the best average level of accuracy among all satellite navigation systems.

Photo by Tunahan Ürkmez on Unsplash

This makes a huge difference regarding the performance of location-based apps and the user experience in the European region.

The list of use-cases to highlight this point is vast so I’ll have to be concise here. Take delivery in densely populated areas with a lot of apartment complexes. With Galileo guiding you along the way, that could make the difference between a lost/late order and one that arrives on time. Customer satisfaction can improve greatly. Knowing that you’ll have the most accurate navigation system available is a boost in confidence in the location deliverance of your app.

One final reminder, if you're interested in learning more about the topic I recommend watching the 20-minute "History 101" episode.

And if you're interested in anything else related to location technology, check out the rest of our blogs!