How to record locations more precisely than GPS, using an Android phone as a GNSS receiver

1. On an Android phone, log the raw GNSS data using one of the following apps. For each location you want to measure, capture 5 minutes of data.
   • GnssLogger by Google > Log
   • GPSTest by Sean Barbeau > Settings > Logging and Output
2. Transfer the log file to a desktop computer (Windows, Linux, or iOS).
3. Run the GNSS Logger desktop app to re-analyze the log data.

For more information about how this improves the precision, and why it can only be obtained after re-analysis and not in real-time, see this.