Your phone with and without a high speed GPS
Have you ever looked at logged GPS data on your phone, tried to get more insight on what made that 1:38 lap better than all of your 1:40 laps, but the data just shows a bunch of jagged lines? You're not alone - that's why we made the GPS_BT.
This image shows an export from Harry's Lap Timer using the built-in GPS next to a lap that used the GPS_BT on the same track with the same car. With just the phone, jagged lines don't tell you if you lifted, if you were just shifting, or if the phone just didn't record a point properly.
With a better GPS, you can see every transition, your exact line on the track, and every area for improvement.
Special thanks to Brandyn Kai and his awesome BRZ for the data!