GPS Distance Accuracy Test: Smartphone Apps vs. Dedicated GPS - Singletracks Mountain Bike News
GPS on smartphones: Testing the accuracy of location positioning
Smartphone GPS accuracy study in an urban environment | PLOS ONE
Galileo Hits the Spot: Testing GNSS Dual Frequency with Smartphones - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design
Best practices for better GPS accuracy in the field | Get Rugged