What hardware aspects of a dedicated GPS running watch make it more accurate than your phone?

My reading of it is that it is a combination of things. Firstly watches often have a better view of the sky rather than a phone on an upper-arm band or in a pocket on your back. Combine that with GPS aerials which may be obscured by electronics, positioned best for use in cars etc on phones, and the GPS watch is a better device.

Secondly, and I think this is the most important, the software / firmware on watches is written to help support reporting of a pace profile which reflects the way people run. I could be wrong about this, but I think the Garmin watches (for which I have experience) do some interpolation of the points in software, rather than just accepting the raw GPS data point that has been received.

Thus when GPS trails are reported from watches, whilst they are still a series of dots joined together, they have more of a tendency to report a smooth(er) more realistic pace and route. Whereas often running apps on phones seem to provide a jerkier output, which makes me think their software either doesn't do a job of smoothing, or does a worse job.

And finally I think what you say about phones being multitasking devices can contribute. I don't know about the lottery approach to getting access to GPS, but certainly they are doing a lot more than a watch is simultaneously.

It’s probably the one second recording in the watches vs the phone (guessing the phones aren’t as quick in order to save battery). Or positioning of the receiver vs other antenna. Certainly less interference.

And batt life in general. No fancy screens (in Garmin) less to power.

This should answer your question:

https://www.androidcentral.com/how-does-gps-work-my-phone

As Iarkimm said, it's the second one. The GPS watch does some things to make assumptions of your pace when the GPS itself isn't getting the job done. It can also look at your cadence to know if you've sped up or slowed down between a lack of data points. It looks at your cadence and looks at historical paces for that cadence for that runner. If you use a watch in indoor mode (without GPS) it will give you a distance based its best best using your cadence.

Phones are typically more accurate than GPS watches. The point of a watch isn't its accuracy; it's that it's convenient to take with you and use while actually running.

annyomouse user name wrote:

It’s probably the one second recording in the watches vs the phone (guessing the phones aren’t as quick in order to save battery). Or positioning of the receiver vs other antenna. Certainly less interference.

And batt life in general. No fancy screens (in Garmin) less to power.

1 point per second doesn't use any algorithmic smoothing of data points. I find 'Smart' mode to be much better. Garmin has gotten pretty good with their software lately.

A watch with a barometric altimeter is more accurate on hills. The GPS sensors on a watch are usually better than a phone (it’s not somewhere phone designers and manufacturers budget a lot of money).

Outside of accuracy issues, watches also weigh less, and operate more reliably in extreme environments.

Phones are just not optimized for GPS tracking.

Neither are perfect. Run with a group and none are exactly the same.

The antennas are a key limiting factor rather than the GPS unit per se.

GPS by itself is only good for 3-8m accuracy in good conditions (eg full view of the sky) b/c of timing accuracies. There are advanced hardware/algorithmic methods for better accuracy but those are only available with survey grade units (such as carrier phase difference methods). Phones and watches are typically just smoothing solutions with something like a kalman filter rather than performing real time error modeling/correction.

There are a variety of correction services that units can connect with that broadcast info to improve a units solution (eg ionospheric interference ), some are subscription based. I’m not aware of any Watches that are configured to connect with these services. Phones, at least, augment their GPS solution calcs with position info from cell towers. I’d love to see an actual breakdown of a watch’s hardware and software, along with an error analysis... but these things aren’t usually public.

A watch is small and fits on your wrist. A phone does not.

Trump wrote:

A watch is small and fits on your wrist. A phone does not.

Only for people with small hands, like Trump.

In Garmin devices the difference between “Smart” and “1 Second” recording only affects what is written to the file. The actual signal reading frequency is the same for both but smart only writes to the FIT file every 5-7 seconds to keep the file size down.

This was useful when memory chips didn’t hold as much and files had to be transferred either via cable or an Ant+ stick attached to your computer but these days the watches have plenty of memory and files are transferred by BT or WiFi so file size isn’t as big of an issue.