I found this a simple read about my gps unit and how it does what it does.
apple.news/AU02JQbEDTn2WtyxBMpe1Xg

An interesting read to explain some of the basics of GPS. But the numbers quoted are misleading. Normal consumer GPS may be capable of 1m accuracy in perfect conditions but that is very rare. Normally, it is far less than that in Australia.
Also, cm accuracy has been available to the civilian market for a long time, but it requires expensive Survey grade equipment and a subscription the a base station correction service in Australia, which makes it not practical for consumers. Surveyers and farmers are it's main users.

Some new consumer GPS, (like the Motion), can simultaneously use multiple satellite Global Navigation Satellite Systems (GNSS) which include GPS, Glonass and Galileo to access a lot more satellites for their solution. A typical 'GPS only' device can sometimes have only 5 satellites available to it, which can degrade it's positional accuracy quite a bit. With Multi GNSS, a device is able to use up to 30+ satellites at any one time. This allows more reliable and accurate positioning accuracy.

I have recently seen some articles about some smartphone companies trying to implement dual frequency GPS for Decimeter accuracy in their top of the line models, but it seems to not be an actual practical reality just yet. It's probably not far off though.

^^^ some news on potential improvement in GPS accuracy:
www.abc.net.au/news/science/2019-03-24/gps-global-positioning-system-sbas-navigation-satellites/10919852?pfmredir=ms

I think most smartphones produced in the last few years already support multiple GNSS systems, of which GPS is just one. It's a bit hard to understand why the GW-60 only supports GPS - that has occasionally lead to problems already. Great to have an alternative with the Motion now!

There's an article about phones that support dual-frequency GPS at https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c. Interestingly, the company that seems to be the first to support the technology seems to be Xiaomi, a Chinese telecom. The accuracy improvements probably won't be dramatic - more like going from 3 m positioning error to 1 m. However, the improvements might be larger in problem environments like "urban canyons". Some of the big accuracy improvement in the newest Snapdragon and u-blox chips are from better "dead reckoning", though - something that's great for cars driving through tunnels, but not for windsurfing! If we suddenly use GPS reception, chances are it was a catapult, and we are not still going at the same speed .

Select to expand quote

boardsurfr said..
I think most smartphones produced in the last few years already support multiple GNSS systems, of which GPS is just one. It's a bit hard to understand why the GW-60 only supports GPS - that has occasionally lead to problems already. Great to have an alternative with the Motion now!

Multi-GNSS requires a bigger antenna because it has to handle wider-bandwidth of the different central-frequencies for differing GNSS systems.

It also requires twice as much silicon, and faster cpu.

mathew's right. And multi-band requires yet more antennas.

Improvements will also come from the upgrades currently being made in space.