How GPS Coordinates & Speedometers Work
The Global Positioning System (GPS) is a network of over 30 satellites orbiting Earth. Your smartphone receives radio signals containing satellite timestamps to compute your exact 3-dimensional position using spherical trilateration.
Decimal Degrees (DD) vs. DMS Format
Two primary coordinate formats are widely used:
- Decimal Degrees (DD): e.g.,
28.6139° N, 77.2090° E— Standard for web mapping, APIs, and digital databases. - Degrees, Minutes, Seconds (DMS): e.g.,
28° 36' 50" N, 77° 12' 32" E— Traditional nautical, aviation, and paper topographic map format.
GPS Accuracy on Mobile Phones
Under an open sky, modern dual-frequency GNSS receivers on smartphones typically achieve horizontal accuracy within ±3 to ±5 meters. Indoors or in dense urban canyons surrounded by skyscrapers, accuracy may degrade to ±15–30 meters due to multipath signal reflection.