The impending launch of Galileo

29 March 2016

Interview with

Dr Chaz Dixon, Technical Director of GNSS at Catapult.

Europe's Galileo will soon be operational, providing us with much more accurate The Galileo spacecraftnavigation but why do we need it given we have GPS and other systems in place? As Chaz Dixon explained to Graihagh Jackson, there are some politics involved as well as the need for better accuracy...

Chaz - The thing that excites me is that Galileo, which has been coming and coming and coming for so many years, is finally going to be here and we're going to have huge capabilities coming down the pipeline, higher accuracy, higher availability through that multi-GNSS world.  I'm a long term GNSS geek.

Graihagh - That's definitely a very geeky thing to look forward to, I'll give you that...

Chaz - I'm afraid so.  Long term nav geek.

Graihagh - You've made me excited through for it so... here, here!

I just love it when you meet someone who is enthralled as Chaz is about their work. Now, back to Galileo, why is he so excited?

Chaz - The whole space is growing very much at the moment.  We've had GPS now for 20 years, the American system.  Europe is just about to introduce it's own so that will be declared operational this year.  It's not yet complete but it will be in an operational state and we'll be able to use that combined with the American GPS system, the Russian Glonass, and the Chinese are also developing a system called Badowl.  So all of that's combining to give more capability to an individual user/receiver.

Graihagh - Why do we need another one given that you've just mentioned there are several already there?

Chaz - Well it's a complex answer to that question.  There are all kinds of political reasons why you might want one.  If we look purely at the engineering side, typically there would be 8 or 10 satellites visible with an open sky but with high rise buildings both sides of the road, a GPS receiver in a mobile phone, on a watch, in a car, might only be seeing one or two signals at any given time...

Graihagh - And you need three?

Chaz - You need four typically to navigate and there's a complexity if you use multiple systems because they use different time standards so typically, when you add each system, you may need an extra measurement.   So with GPS you need four measurements, if you add GPS to Glonass you might need five measurements, if you add Gallileo you might need six measurements, but each of these constellations is typically 30 satellites.  The one or two GPS combined with the one or two Glonass, with the one or two Galileo, etc, mean that you have all of the necessary positioning capability in a dense urban environment.

Graihagh - It doesn't just mean I can find my way around London easier - As more of us live in cities, we'll also need more frequent trains, as those of us who frequently play a game of sardines on the commute to work will be wanting sooner rather than later. Because railway signalling systems are still relatively unsophisticated, it means that for safety reasons trains have to be well-separated. With Galileo, that becomes much less of an issue. And then there's the whole driverless car thing...

Chaz - That becomes exciting into a future where the controller of a vehicle might not be a person, because a person will drive their car along a street and not in a field.  But now, if you put a robot in charge of that vehicle, you have to give the robot the capability to know the difference between an urban street and the countryside and it has to be able to do that in the fog, or in the rain, or in whatever conditions it is.

Graihagh - So that's when GPS becomes really, really important and having that accuracy and that coverage?

Chaz - Exactly so and that multi-GNSS capability in an urban environment becomes really important.

Graihagh - Will you be getting a driverless car?  Will you be trusting GNSS?

Chaz - Not this year.  Maybe one day!

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