There's an interesting blog post over at map makers HERE (ex-Nokia, of course, but hey....), chatting about why we need extra positioning systems in our smartphones and other devices. We've been used to GPS for a decade or two - Russia's GLONASS system joined it in the last five years (for consumers), and imminent is China's BeiDou (BDS), but did you know that the likes of the Lumia 950, 950 XL and 650 support all three sets of satellites? In other words, something in the order of 70 satellites are being accessed by our smartphones daily, whenever we navigate. Explaining the lightning fast fixes and accuracy of the fixes!

From the HERE blog post:

...there are actually two fully-operational global navigation satellite systems (or GNSS, for short).

GPS was developed in the late 1970s by the US, and it has gown – in size and popularity – ever since. But, contemporaneously, Russia developed GLONASS and by 2012, it had become the second-most-used positioning system in mobile phones. In many ways, GLONASS and GPS are very similar – they each started as military projects, they offer global coverage with similar precision, and they use microwave frequencies to transmit their data. So, on first glance, it can be hard to see why we need both.

And that’s not all – GPS and GLONASS are being joined by two additional global constellations – Europe’s Galileo, and China’s BeiDou, which together, will more the double the number of navigation satellites in orbit around Earth.

...And this is really where Galileo project comes in. It is being built by the European Commission and the European Space Agency as a civilian navigation tool – one that can operate independently from GPS or GLONASS.

As of May 2016, 14 Galileo satellites were in orbit, with 16 more to come online in the next four years, providing global coverage, and improved precision. Importantly, Galileo will also work alongside other systems to form a global search and rescue system – a near-instantaneous, worldwide distress beacon locator.

Regional development

A number of countries, such as India and Japan, have taken a different approach – developing constellations that offer high-precision coverage over a limited region. China’s BeiDou system started off in the same way, but by 2020, they’ll have 30 satellites in orbit, making it the fourth truly global navigation system. The primary argument for BeiDou is to maintain China’s independence, but there are also financial gains from satellite-based positioning systems. According to China Daily, BeiDou is already generating $31.5 billion for the economy. Part of this is because navigation satellites offer more than just positioning. Atomic clocks on-board can measure time to within 100 billionths of a second, allowing us on the ground to freely and accurately manage everything from electricity networks to financial markets.

Aside from faster fixes and more reliable positioning, there are accuracy benefits too. By starting from scratch at the design stage, Galileo in particular might stand out:

...the Galileo signals could offer much better services than those we have today. All the research suggests that by combining particular frequencies unique to Galileo, called AltBOC, it may be possible to reach decimetre (10 cm) level positioning.

And then there is the benefit of competition – “If you have a single system, it’s very easy to become complacent”, said Moore “GPS and GLONASS have been pushed into modernisation because of the development of Galileo.”

The three Lumias mentioned earlier support three of the four big systems, older Windows Phones support just GPS and GLONASS. Thankfully all of this is transparent to the consumer, and there's even a hope that all four systems will eventually be 100% compatible:

So what will these multiple GNSS systems mean for us? Well, most smartphones and in-car systems already flick between GLONASS and GPS when they need to. Eventually though, the hope is that all four global positioning systems will speak the same language (interoperable with the GPS L1C signal). For the average consumer, that should mean more accurate timing and better positioning services even in built-up areas, anywhere in the world.

A very interesting article. I, for one, had never even heard of BDS and didn't know that my current phones work with it! And although no current phone currently works with Galileo, I'm sure that new devices will in 2017 and beyond. 

I'm not quite sure why we need (theoretical) 10cm accuracy in the civilian world, but pedestrian navigation and footpaths spring to mind at the metre level. Maybe there are uses for positioning systems to help us track dogs and other pets? Most super-accurate positioning is surely best used by the military and commercial outfits?