I'd suggest checking more long term to see how stable the phone is. Typically the phone stuff also has a much slower refresh rate. I tried doing some telemetry during autocross with my phone GPS and found it nearly useless. It was refreshing too slowly, and accuracy was intermittent. At times I'd get a 5m accuracy, other times I'd be lucky if the phone saw me being within a quarter mile of my location. This was with a few generations of iphones. I eventually gave up and got an external GPS receiver, which worked great until they stopped updating the associated app for newer generations of IOS. Now this is with actual GPS data, the cellular locating data tends to be more stable as long as you're in good coverage, though not as accurate.
-Hans